---
slug: thymosin-alpha-1
title: "Thymosin Alpha-1: Approvals, Trial Record, Dosing and What It Does Not Treat"
kind: essay
status: published
hash: 85b7c01ffbf7cb856e0f55e4f63d0483b3ee78751d60b08097bd343653f8b2c3
created: 2026-06-29 08:23:19
updated: 2026-10-08T11:51:33.732Z
summary: "Thymosin alpha-1 is a chain of 28 amino acids that the thymus gland releases into the blood, where it tells immature T cells to finish growing up. The synthetic copy is called thymalfasin, it is sold as Zadaxin, and it is a licensed"
tags: ["peptide","thymosin-alpha-1"]
above: []
below: []
adjacent: []
nested: []
---
# Thymosin Alpha-1: Approvals, Trial Record, Dosing and What It Does Not Treat

*Thymosin alpha-1 is a chain of 28 amino acids that the thymus gland releases into the blood, where it tells immature T cells to finish growing up. The synthetic copy is called thymalfasin, it is sold as Zadaxin, and it is a licensed*

Thymosin alpha-1 is a chain of 28 amino acids that the thymus gland releases into the blood, where it tells immature T cells to finish growing up. The synthetic copy is called thymalfasin, it is sold as Zadaxin, and it is a licensed prescription medicine in roughly 35 countries — which makes it the only compound in this library that a drug regulator anywhere has ever approved.

That single fact reorders everything else, so take the evidence state before anything is argued from it. Most peptides in this library have animal data and a handful of uncontrolled human reports. Thymosin alpha-1 has 63 studies registered on ClinicalTrials.gov, four completed phase 3 programmes, a licensed package insert with a real dosing schedule, and more than 3,000 patients dosed across over 70 studies since 1979. Two of the randomised trials are large and both missed their main endpoint: TESTS, 1,106 adults with sepsis, where 28-day death was 23.4% against 24.1% on placebo; and TRACE, 508 people with severe pancreatitis, where infected dead tissue came out at 15.7% against 18.1%. Two results went the other way: in chronic hepatitis B on its own the odds of clearing the virus and holding it cleared came out 2.87 times placebo, and in a 120-person randomised trial in dialysis patients the drug carried a flu vaccine over the European licensing threshold that the vaccine alone did not reach. One observational study in COVID-19 recorded worse outcomes. The animal record is mice, and its cleanest single result is that the whole effect vanishes in mice bred without the TLR9 receptor. Then the absence that governs this page: across all 63 registered trials there is no tendon, no ligament, no disc, no muscle and no joint. Nothing has been measured in a person for any musculoskeletal problem, and no animal model of one has been run either.

One disclosure, because it should change how you read the rest. The operator of this site has a commercial interest in compounds described here. That is a reason to weigh what is on this page against the sources it cites rather than against its tone, and every claim below carries the source that supports it for exactly that reason.

```widget
{
  "type": "source",
  "id": "w_18bl3rtc"
}
```

## Approved in Beijing, unapproved in Bethesda

Thymalfasin holds marketing approvals for chronic hepatitis B, chronic hepatitis C, use as a vaccine adjuvant in immunocompromised patients, and certain cancers, with the exact indication set varying by country. The United States is not among them. Neither is the European Union.

| Jurisdiction | Status | Indications where approved |
|---|---|---|
| China | Approved; marketed as Zadaxin and by domestic manufacturers | Hepatitis B, immune enhancement, vaccine response, critical-illness adjunct |
| Italy | Approved | Hepatitis B, hepatitis C |
| Roughly 35 countries in total | Approved | Hepatitis B, hepatitis C, vaccine adjuvant, certain cancers, per each national label |
| United States | **Not approved.** No Drugs@FDA entry, no FDA-approved label, no openFDA label record | None |
| European Union | **Not approved** | None |

The manufacturer's own monograph puts the count at "over 30 countries" and states the exclusion in one sentence: "ZADAXIN has not been approved for sale in the United States or Europe." The peer-reviewed literature puts it at "more than 35 countries."

```widget
{
  "type": "source",
  "id": "w_d85m6gah"
}
```

```widget
{
  "type": "source",
  "id": "s1"
}
```

The US absence is not a rejection on the merits. No sponsor has completed a US registration filing. Thymalfasin has held FDA orphan drug designations — for malignant melanoma, chronic active hepatitis B, DiGeorge anomaly with immune defects, and hepatocellular carcinoma. A designation is a development incentive: fee waivers, tax credits, and seven years of market exclusivity if the drug is later approved. It is not an approval, it permits no marketing, and it carries no finding about whether the drug works. Sources that describe those designations as approvals are wrong, and the distinction is the whole of the US position.

## Withdrawn from the danger list is not the same as cleared for use

The entire United States position turns on one table on one FDA page, and the row is easy to misread.

FDA maintains a page titled *Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks*. It carries two tables. The first is Category 2 proper — substances FDA has flagged as posing significant safety risks, which bars compounding under the interim policies. The second is headed *Bulk drug substances nominated but withdrawn*, described as substances "previously in category 2 of the interim policies" that "were withdrawn by the nominators."

Thymosin-alpha 1 sits in the second table, alongside BPC-157, KPV, TB-500, epitalon, semax, selank and DSIP. FDA's recorded concern reads:

> Compounded drugs containing thymosin-alpha-1 (Ta1) may pose significant risk for immunogenicity for certain routes of administration and may have complexities with regard to peptide-related impurities and API characterization. The safety-related information is inadequate for the agency to sufficiently understand the extent of any safety issues raised by the proposed compounded drug.

```widget
{
  "type": "source",
  "id": "w_uzdfttix"
}
```

Three consequences follow, and they are not the same as each other.

Withdrawal is a procedural act by the party who filed the nomination. It removes the substance from the active Category 2 listing. It is not FDA finding the substance safe, and no agency review concluded in the substance's favour.

Absence from Category 2 creates no permission. To be lawfully compounded from a bulk substance under section 503A, a substance must be the subject of an applicable USP or National Formulary monograph, be a component of an FDA-approved drug, or appear on the 503A bulks list. Thymosin alpha-1 is none of the three in the United States. The 503B outsourcing-facility channel is separate, narrower, and does not list it either.

The practical position in the United States is therefore an unapproved drug obtainable only through the grey market or a compounder operating outside the bulks framework. Any source still describing it as "FDA Category 2" is quoting a status the current page no longer assigns to it. That page was last updated 22 April 2026.

## It gives back a signal the thymus stops sending

The thymus is largest in childhood and shrinks from puberty onward. By the sixth decade most of its functional tissue has been replaced by fat, and the output of new naive T cells falls with it. Thymosin alpha-1 is one of the peptides that tissue secretes; circulating levels in healthy adults run between 0.1 and 1 ng/mL and are lower in disease.

The mechanism reads as a chain. The links are not equally well established, and the difference matters.

**Step one — it binds Toll-like receptors on dendritic cells.** This is the anchoring finding and it is demonstrated directly. In mice, thymosin alpha-1 activated plasmacytoid dendritic cells through TLR9 and MyD88, switching on interferon regulatory factor 7 and driving an interferon-alpha and interferon-gamma effector response. Mice lacking TLR9 lost the protection. That is a knockout-confirmed dependency, not a correlation.

```widget
{
  "type": "source",
  "id": "w_e7vuijxz"
}
```

**Step two — the dendritic cell decides what kind of immunity follows.** Dendritic cells read an infection and instruct the rest of the immune system. Priming them through TLR/MyD88 produced Th1-type antifungal resistance in living animals. The same work found thymosin alpha-1 inducing indoleamine 2,3-dioxygenase in dendritic cells — the enzyme that pushes toward tolerance rather than attack.

```widget
{
  "type": "source",
  "id": "w_pptae9m4"
}
```

**Step three — T cells mature and differentiate.** The 1972 characterisation was of a thymic fraction that restored immune function to thymectomised mice. The measurable human version is a rise in CD4+ percentage and a normalising CD4+/CD8+ ratio. A meta-analysis of five randomised trials in severe acute pancreatitis quantified it: CD4+ percentage rose by 4.53 points (95% CI 3.02 to 6.04) and the CD4+/CD8+ ratio by 0.42 (95% CI 0.26 to 0.58). CD8+ counts did not fall significantly, which is the point — the ratio normalised by lifting the deficient arm.

```widget
{
  "type": "source",
  "id": "s7"
}
```

**Step four — natural killer cells and cytotoxic T lymphocytes.** Thymosin alpha-1 modulates NK cell maturation and cytotoxic T lymphocyte responses, and raises MHC class I surface expression on tumour cell lines. The target cell becomes easier to see, not only the effector cell more aggressive.

```widget
{
  "type": "source",
  "id": "w_ekm6tk8i"
}
```

**Step five — reversal of T-cell exhaustion.** In severe COVID-19 patients, treatment was associated with reduced PD-1 and Tim-3 expression on CD8+ T cells and a rise in T-cell receptor excision circles, the standard marker of fresh thymic output. This is observational human data from a retrospective cohort of 76 patients, not a controlled experiment, and it belongs in a different evidentiary tier from step one.

```widget
{
  "type": "source",
  "id": "w_or6weneu"
}
```

What separates this compound from a stimulant is that the same molecule pushes in opposite directions depending on the state it finds. It induces tolerance-promoting IDO in one context and interferon-driven antiviral attack in another. That bidirectionality is why the literature calls it restoration rather than stimulation. It is also why the dose-response is not a straight line, and why the sepsis subgroups below point in opposite directions in different patients.

```widget
{
  "type": "source",
  "id": "s2"
}
```

## Sixty-three registered trials, and the two largest disagree

Sixty-three studies are registered on ClinicalTrials.gov with thymosin alpha-1 as an intervention. The named human record is set out below with the result stated as each trial reported it, including the failures.

| Trial | NCT | n | Population | Dose | Duration | Primary endpoint | Result |
|---|---|---|---|---|---|---|---|
| TESTS — phase 3, quadruple-blind, 22 centres | NCT02867267 | 1,106 | Sepsis-3 adults, 18–85 | 1.6 mg SC every 12 h | ≤7 days | 28-day all-cause mortality | **Missed.** 23.4% vs 24.1% placebo; HR 0.99 (0.77–1.27); P=0.93 |
| ETASS — RCT, single-blind, 6 centres | NCT00711620 | 361 analysed | Severe sepsis | 1.6 mg SC twice daily ×5 d, then daily ×2 d | 7 days | 28-day all-cause mortality | Borderline. 26.0% vs 35.0%; RR 0.74 (0.54–1.02); P=0.062 unstratified, 0.049 log-rank |
| TRACE — phase 4, double-blind, 16 centres | NCT02473406 | 508 | Predicted severe acute necrotising pancreatitis | 1.6 mg SC q12h ×7 d, then daily ×7 d | 14 days | Infected pancreatic necrosis | **Missed.** 15.7% vs 18.1%; difference −2.4% (−7.4 to 5.1); P=0.48 |
| TRACE post-hoc, lymphocyte-stratified | NCT02473406 | 290 of 502 | Same trial, baseline ALC ≥0.8×10⁹/L | as above | 14 days | Infected pancreatic necrosis at 90 d | Positive in subgroup. Adjusted risk difference −0.12 (−0.21 to −0.02); P=0.015 |
| Hepatitis C non-responders — phase 3, 52 European sites | NCT01178996 | 552 | Chronic HCV, prior peg-IFN + ribavirin failure | 1.6 mg SC twice weekly + peg-IFN α-2a + ribavirin | 48 weeks | Sustained virological response at week 72 | Completed July 2009. **No results posted or published** |
| Hepatitis C non-responders, non-cirrhotic — phase 3 | NCT00040027 | 500 | Chronic HCV interferon non-responders | 1.6 mg twice weekly + peg-IFN α-2a | — | Virological response | Completed. **No results posted** |
| Metastatic melanoma — phase 2, dose-ranging, 5 arms | NCT00911443 | 488 | Stage IV melanoma | 1.6, 3.2 or 6.4 mg SC on days 8–11 and 15–18 of each 28-day cycle | ≤6 cycles | Overall tumour response | Responders 7/97, 10/97, 6/98, 12/99 in the four Tα1 arms vs 4/97 control. Median OS 8.6–10.3 months vs 6.6 |
| COVID-19 prevention in dialysis — phase 2 | NCT04428008 | 189 | ESRD on haemodialysis | 1.6 mg SC | 6 months | Number infected with COVID-19 | 5/91 treated vs 7/98 control. Deaths 3/91 vs 7/98. Underpowered for both |
| COVID-19 with lymphocytopenia — phase 2 | NCT04487444 | 56 | Hospitalised, lymphocytopenic | 1.6 mg SC daily ×7 d | 1 week | Time to freedom from respiratory failure | **Terminated** February 2023. No results posted |
| H1N1 vaccine adjuvant pilot | NCT01031966 | 120 enrolled, 94 ITT | ESRD on chronic dialysis | 3.2 mg or 6.4 mg on day −7 and day 0 | 2 doses | Antibody response measured by haemagglutination-inhibition | Positive. CHMP licensing criteria fully met in both Tα1 arms, not in vaccine-only |
| Colorectal cancer adjuvant — phase 3 | NCT05086614 | 2,500 planned | Resected high-risk stage II/III colorectal cancer | 1.6 mg SC twice weekly | 6 months | 3-year disease-free survival | **Recruiting.** Primary completion March 2027 |
| Acute aortic dissection, immune dysregulation | NCT05339529 | 330 | Post-operative acute aortic syndrome | Per protocol | — | Organ dysfunction | Recruiting |
| Vaccine response in older adults — phase 1 | NCT06821100 | 75 | Adults over 65 receiving COVID-19 vaccine | Per protocol | — | Immune response | Recruiting |

```widget
{
  "type": "source",
  "id": "w_vzvtwnky"
}
```

```widget
{
  "type": "source",
  "id": "w_zlvvtukb"
}
```

## Hepatitis is the indication the licences rest on

The approvals were granted on chronic hepatitis B. An independent meta-analysis of 435 patients across randomised controlled trials of thymalfasin monotherapy found a sustained virological response advantage over placebo with an odds ratio of 2.87 (95% CI 1.58–5.22, P=0.0005), and a non-significant trend favouring it over interferon alpha (OR 2.62, 95% CI 0.80–8.56). Across the individual monotherapy studies, disease remission ran 26% to 41%.

```widget
{
  "type": "source",
  "id": "w_d85m6gah"
}
```

Two caveats belong in the same breath. The comparator was interferon or placebo, in an era before tenofovir and entecavir; a 2020 review states plainly that hepatitis B and C treatment with thymosin alpha-1 "has been discontinued in favor of direct antiviral agents." And the two large phase 3 hepatitis C programmes in non-responders — 552 and 500 patients, both completed more than fifteen years ago — have never reported. A completed 552-patient phase 3 with no published outcome is not neutral evidence about a drug; it is a hole where the answer should be.

```widget
{
  "type": "source",
  "id": "w_xmbjsj3u"
}
```

## Sepsis is where it was tested hardest and came up short

ETASS in 2013 was the encouraging trial. 361 patients, 28-day mortality 26.0% on thymosin alpha-1 against 35.0% on control, plus a measurable rise in monocyte HLA-DR — the clearest available marker of reversed immunoparalysis — at day 3 (mean difference 3.9%, 95% CI 0.2–7.6) and day 7 (5.8%, 95% CI 1.0–10.5). The mortality difference did not clear significance on the primary unstratified analysis at P=0.062.

TESTS was built to settle it. 1,106 patients, 22 centres, quadruple-blinded, placebo-controlled, phase 3. It found nothing: 28-day mortality 23.4% against 24.1%, hazard ratio 0.99, P=0.93. No secondary endpoint separated, and no safety endpoint separated either.

The subgroup analysis is where it stops being simply negative. Patients under 60 did worse on the drug (HR 1.67, 1.04–2.67). Patients 60 and over trended better (HR 0.81, 0.61–1.09). Interaction P=0.01. Diabetic patients did better (HR 0.58, 0.35–0.99), non-diabetic patients did not (HR 1.16, 0.87–1.53), interaction P=0.04. These are prespecified subgroups inside a negative trial. They are hypotheses, and a younger patient doing worse on an immune-restoring drug is a hypothesis worth taking seriously in both directions.

A 2025 meta-analysis pooled 11 randomised trials and 1,927 patients. Overall it found a 28-day mortality benefit (OR 0.73, 95% CI 0.59–0.90, P=0.003). That benefit disappeared when restricted to high-quality trials (OR 0.82, P=0.09) and to multicentre trials (OR 0.86, P=0.20). Trial sequential analysis concluded the accumulated sample is still inadequate to answer the question.

```widget
{
  "type": "source",
  "id": "s27"
}
```

## Pancreatitis: the trial missed, and one subgroup did not

TRACE randomised 508 patients with predicted severe acute necrotising pancreatitis, 94.3% of whom required intensive care. Infected pancreatic necrosis occurred in 15.7% of treated patients and 18.1% of placebo patients, P=0.48. New-onset organ failure, bleeding and gastrointestinal fistula were all similar between arms.

```widget
{
  "type": "source",
  "id": "w_0c2625io"
}
```

The post-hoc analysis found what the whole trial did not. Among the 290 patients whose baseline absolute lymphocyte count was at or above 0.8×10⁹/L, thymosin alpha-1 reduced infected necrosis with an adjusted risk difference of −0.12 (95% CI −0.21 to −0.02, P=0.015). Patients between 0.79 and 2.00×10⁹/L benefited most.

```widget
{
  "type": "source",
  "id": "w_cbj4dxj3"
}
```

Read carefully, that is the single most informative result in the file. An immune-restoring drug worked in the patients who still had lymphocytes to restore and did nothing in the patients too depleted to respond. It is post-hoc, it needs prospective confirmation, and it explains why an unselected population produces a null. It also implies that any honest use of this compound starts with a lymphocyte count.

## COVID-19 produced three answers, and one of them was harm

The Wuhan retrospective covered 76 severe cases and reported mortality of 11.11% with treatment against 30.00% without (P=0.044), alongside restored CD8+ and CD4+ counts and reduced exhaustion markers.

```widget
{
  "type": "source",
  "id": "w_or6weneu"
}
```

A five-hospital multicentre cohort of 2,282 patients found the reverse. After adjustment for confounders, thymosin alpha-1 use was associated with a *higher* non-recovery rate (OR 1.5, 95% CI 1.1–2.1, P=0.028), with risk concentrated in patients with SOFA scores of 2 or more, ICU admission, and lower PaO₂/FiO₂. Later initiation was worse than earlier.

```widget
{
  "type": "source",
  "id": "w_q4kpjhai"
}
```

A propensity-matched cohort of 1,388 non-severe patients found no difference in progression to severe disease (2.17% vs 2.71%) or in mortality, but shorter viral shedding (13 vs 16 days, P=0.025) and shorter hospital stay (14 vs 18 days, P<0.001).

```widget
{
  "type": "source",
  "id": "w_vxfrwa56"
}
```

All three are observational and all three are subject to confounding by indication — sicker patients get more drugs. The only randomised study that targeted the lymphocytopenic patients the mechanism predicts should respond was terminated at 56 patients and never reported.

## Vaccine response is the cleanest positive signal in the file

Haemodialysis patients mount poor antibody responses to influenza vaccine. In the pilot trial, patients given the adjuvanted H1N1 vaccine alone did not meet the CHMP licensing criteria for seroconversion, seroprotection and geometric mean ratio. Patients given the vaccine plus 3.2 mg or 6.4 mg of thymosin alpha-1 on day −7 and day 0 met all three. No adverse event was attributed to the peptide, and no change appeared in haematology or blood chemistry.

```widget
{
  "type": "source",
  "id": "w_23spjiq3"
}
```

This is 94 patients in an intention-to-treat analysis, in a population defined by immune failure, in a pilot study. It is also the one result where the drug did the specific thing its mechanism predicts, in humans, judged against a prespecified regulatory standard rather than an author's own endpoint.

## The cancer file is adjuvant work with one real trial still running

The melanoma dose-ranging study is the largest completed oncology dataset: 488 patients across five arms, responses in 6 to 12 patients per thymosin arm against 4 of 97 in the dacarbazine-plus-interferon control, and median overall survival of 8.6 to 10.3 months against 6.6. It was a phase 2 designed to select a dose, not to prove survival, and no phase 3 followed it in the nineteen years since it started.

```widget
{
  "type": "source",
  "id": "w_omh8z65r"
}
```

The trial that would settle the oncology question is enrolling now: 2,500 patients with resected high-risk stage II and III colorectal cancer, randomised to 1.6 mg twice weekly for six months or to no thymosin, with three-year disease-free survival as the primary endpoint and primary completion in March 2027.

```widget
{
  "type": "source",
  "id": "w_dkfbbahz"
}
```

## Every trial population is an infection, an organ failure or a cancer, and not one of them is a back

Every trial population above is a hepatitis patient, a septic ICU patient, a pancreatitis patient, a cancer patient, or a dialysis patient. Not one is a back-pain patient. There is no musculoskeletal indication, no tendon, ligament, disc or muscle model, and no mechanism connecting T-cell maturation to tissue repair.

| What brings a person to look this up | What the human record actually covers | Strength of the connection |
|---|---|---|
| Recurrent infection, slow recovery from every cold | Vaccine-response pilot in dialysis patients; hepatitis approvals; 3,000-patient safety file | Moderate, and only by extrapolation from immunocompromised populations |
| Documented immunosuppression with a measured low-normal lymphocyte count | TRACE subgroup: the effect appeared where lymphocytes were preserved but suppressed | Moderate. Post-hoc, and it requires the blood test to identify |
| Post-viral fatigue after a confirmed infection | No completed randomised trial. The COVID file is acute hospitalised disease and it contradicts itself | Absent |
| Chronic inflammatory load in a chronic-pain patient | CRP fell 30.12 mg/L in the lower-dose arms of the pancreatitis meta-analysis — in patients with necrotising pancreatitis in intensive care | Absent for this population |
| Immune-related fatigue with no diagnosis and no abnormal labs | No trial, no endpoint, no measurement | Absent |
| Tendinopathy, disc pain, muscle strain, joint repair | No model, no trial, no proposed mechanism | Absent. The extrapolation is unsupported |
| Post-adjustment soreness | Nothing | Absent |
| Hashimoto's, MCAS, ankylosing spondylitis, other autoimmunity | No trial. The mechanism cuts both ways — tolerance in one context, interferon-driven attack in another | Absent, and the self-reports below include people who got measurably worse |

The one row the record can defend is the immune row, in a person with documented immune compromise, and even that defence is an off-label extrapolation from populations that do not look like that person. Selling thymosin alpha-1 for musculoskeletal repair is a claim that nothing in 63 trials supports.

## Dosing, and the arithmetic behind the syringe

The licensed product is a 1.6 mg lyophilised vial supplied with 1.0 mL of Sterile Water for Injection. Reconstituted, that is 1.6 mg/mL, and the whole vial is one dose. The approved hepatitis B regimen is 1.6 mg (900 µg/m²) subcutaneously twice a week for 6 to 12 months. Patients under 40 kg receive 40 µg/kg.

```widget
{
  "type": "source",
  "id": "w_dt6aln8r"
}
```

| Setting | Dose | Frequency | Duration |
|---|---|---|---|
| Hepatitis B — approved label | 1.6 mg SC | Twice weekly | 6–12 months |
| Hepatitis C — phase 3 protocol | 1.6 mg SC | Twice weekly | 48 weeks |
| Sepsis — TESTS | 1.6 mg SC | Every 12 hours | ≤7 days |
| Sepsis — ETASS | 1.6 mg SC | Twice daily ×5 d, then daily ×2 d | 7 days |
| Necrotising pancreatitis — TRACE | 1.6 mg SC | Every 12 h ×7 d, then daily ×7 d | 14 days |
| Colorectal adjuvant — phase 3 | 1.6 mg SC | Twice weekly | 6 months |
| Metastatic melanoma — phase 2 | 1.6, 3.2 or 6.4 mg SC | Days 8–11 and 15–18 of a 28-day cycle | ≤6 cycles |
| Influenza vaccine adjuvant | 3.2 or 6.4 mg SC | Day −7 and day 0 | 2 doses |

The critical-illness regimens run at 3.2 mg per day — twice the hepatitis dose, for one to two weeks. The vaccine regimen runs up to 6.4 mg in a single dose. The cumulative safety record spans 1 mg to 16 mg per dose, and 0.6 to 9.6 mg/m². There is no dose ceiling hiding in that range. There is also nothing showing that a larger dose does more for a stable outpatient.

### Reconstitution, shown as arithmetic

Grey-market vials come as 5 mg or 10 mg of lyophilised powder, not 1.6 mg, so the arithmetic has to be done rather than read off a label.

Concentration in mcg per mL = total micrograms in the vial ÷ millilitres of bacteriostatic water added.
A U-100 insulin syringe holds 1.0 mL across 100 units, so one unit is 0.01 mL, and micrograms per unit = concentration ÷ 100.

Worked: a 10 mg vial holds 10,000 mcg. Add 4.0 mL of bacteriostatic water. 10,000 ÷ 4.0 = 2,500 mcg/mL. 2,500 ÷ 100 = 25 mcg per unit. A 1.6 mg dose is 1,600 ÷ 25 = 64 units on the barrel.

| Vial | Bacteriostatic water added | Concentration | Mcg per unit | Units for 1.6 mg | Full 1.6 mg doses per vial |
|---|---|---|---|---|---|
| 5 mg (5,000 mcg) | 2.0 mL | 2,500 mcg/mL | 25 | 64 | 3, with 200 mcg left over |
| 5 mg (5,000 mcg) | 2.5 mL | 2,000 mcg/mL | 20 | 80 | 3 |
| 5 mg (5,000 mcg) | 5.0 mL | 1,000 mcg/mL | 10 | 160 — two injections | 3 |
| 10 mg (10,000 mcg) | 2.0 mL | 5,000 mcg/mL | 50 | 32 | 6, with 400 mcg left over |
| 10 mg (10,000 mcg) | 4.0 mL | 2,500 mcg/mL | 25 | 64 | 6 |
| 10 mg (10,000 mcg) | 5.0 mL | 2,000 mcg/mL | 20 | 80 | 6 |

At 5,000 mcg/mL — a 10 mg vial in 2.0 mL, the concentration that keeps every trial dose inside one syringe — the conversion is:

| Dose | Micrograms | Units on a U-100 barrel |
|---|---|---|
| 0.25 mg | 250 | 5 |
| 0.5 mg | 500 | 10 |
| 0.8 mg | 800 | 16 |
| 1.0 mg | 1,000 | 20 |
| 1.6 mg | 1,600 | 32 |
| 3.2 mg | 3,200 | 64 |
| 6.4 mg | 6,400 | 128 — two injections |

Below about five units, graduation error on a U-100 barrel starts to dominate the dose, which is the argument for more diluent at the sub-milligram tiers and less at 1.6 mg and above.

Route is subcutaneous in every trial and on every label. Sites are the abdomen at least two inches from the navel, the outer thigh, or the back of the upper arm, rotated between doses. Nothing in the record supports taking this peptide into a muscle, into a vein or by mouth outside a study protocol.

Bring the vial to room temperature before adding water. Run the water down the inside wall rather than jetting it onto the powder. Swirl until dissolved and never shake — shear at the air-liquid interface unfolds peptides and makes them clump, and that clumping is the exact mechanism FDA named when it warned about the immune system reacting to the drug.

### Storage, and the difference the diluent makes

| State | Temperature | Practical shelf life |
|---|---|---|
| Sealed lyophilised vial | 2–8 °C, protected from light | To the manufacturer's date |
| Reconstituted with Sterile Water for Injection — the licensed diluent | — | Use immediately. No preservative present |
| Reconstituted with bacteriostatic water, 0.9% benzyl alcohol | 2–8 °C | About four weeks, set by the preservative rather than by the peptide |
| Reconstituted, held at room temperature | 20–25 °C | Hours to days. Treat as compromised |
| Reconstituted, frozen | −20 °C | Avoid. Freeze-thaw aggregates peptides |

The licensed insert says use immediately because the supplied diluent is preservative-free. A multi-dose vial reconstituted with bacteriostatic water is a different object running a different clock.

### Timelines

Peak serum concentration is reached about 2 hours after a subcutaneous dose, the elimination half-life is about 2 hours, and 31% to 60% of the dose is recovered in urine. The drug leaves the blood the same day. Everything that persists is downstream of what it did to cells, which is why the schedules are twice weekly rather than daily.

| What was measured | When it read out in the trials |
|---|---|
| Monocyte HLA-DR improvement — ETASS | Days 3 and 7 |
| CD4+ percentage and CD4+/CD8+ ratio change | Within the 7–14 day critical-illness courses |
| Vaccine seroconversion — H1N1 pilot | Day 21 after vaccination, dosed day −7 and day 0 |
| Hepatitis B sustained virological response | 6–12 months of dosing, assessed 6 months after treatment |
| Hepatitis C sustained virological response | Week 72, after 48 weeks of dosing |
| Colorectal disease-free survival | 3 years, after 6 months of dosing |

## The safety record is the longest in this library, which is not the same as no risk

Most compounds in this library have no human safety file at all. This one has a specific, quantified record.

Since 1979, thymalfasin has been given to more than 3,000 patients in over 70 clinical studies, at doses from 1 mg to 16 mg, for periods from a single day to 18 months. The monograph's summary sentence is that "no serious adverse experiences have been observed." Patients as old as 101 and children as young as 13 months have been dosed. Patients with decompensated liver disease and patients on haemodialysis tolerated it.

```widget
{
  "type": "source",
  "id": "w_d85m6gah"
}
```

The label puts drug-related adverse events at under 1% across all indications and describes them as "infrequent and mild, consisting primarily of local discomfort at the injection site, and rare instances of erythema, transient muscle atrophy, polyarthralgia combined with hand edema, and rash." It is contraindicated in hypersensitivity to the drug or its components.

```widget
{
  "type": "source",
  "id": "w_dt6aln8r"
}
```

The controlled trials support that. TESTS randomised 1,106 patients and reported no safety outcome differing significantly between drug and placebo. TRACE randomised 508 and found no difference in bleeding, fistula or new organ failure. The H1N1 pilot attributed no adverse event to the peptide. In the dialysis prevention trial, serious adverse events were 28 of 91 on treatment against 26 of 98 on control, and deaths were 3 of 91 against 7 of 98.

```widget
{
  "type": "source",
  "id": "w_jzf25pn3"
}
```

Preclinical toxicity never reached a maximum tolerated dose. Single subcutaneous doses up to 20 mg/kg in mice, rats and marmosets — more than 800 times the human 1.6 mg dose by weight — produced no drug-related toxicity, as did repeat dosing at 6 mg/kg/day for 13 weeks.

Three qualifications matter more than the reassurance.

**Immune activation can itself be the adverse event.** A 29-year-old man with nasopharyngeal carcinoma received a single 1.6 mg subcutaneous dose eleven days after the checkpoint inhibitor sintilimab. Within 48 hours he had fever of 39–40.5 °C, facial rash and oedema, progressive hypoxaemia with interstitial pulmonary oedema, AST of 742 U/L, and a prothrombin time of 23.2 seconds. He required 160 mg of intravenous methylprednisolone daily and was discharged on day 33. He later tolerated a sintilimab rechallenge without recurrence, which points the causal finger at the peptide rather than the checkpoint inhibitor.

```widget
{
  "type": "source",
  "id": "w_c958vpgi"
}
```

**The COVID cohort recorded worse outcomes, not merely absent benefit.** An adjusted odds ratio of 1.5 for non-recovery in the sicker patients is a harm signal, and the mechanism is plausible: adding immune activation to a hyperinflammatory state is not obviously safe.

**FDA's stated concern is manufacturing, not what the drug does in the body.** The risk of the immune system reacting to the drug, raised by clumping and by peptide-related impurities, is a supply-chain problem. The 3,000-patient safety record belongs to a pharmaceutical product made to a licensed specification. A grey-market vial carrying a vendor's own certificate of analysis is not that product, and a cloudy reconstitution is a visible sign of the exact aggregation the agency named.

## What people using it outside the trials report

These are self-reports with dates and permalinks, gathered from public discussion. They are not evidence of whether it works, they are not filtered for anything, and they are here because they show what the experience looks like and how often it goes badly.

```widget
{
  "type": "source",
  "id": "s8"
}
```

```widget
{
  "type": "source",
  "id": "s61"
}
```

```widget
{
  "type": "source",
  "id": "s75"
}
```

```widget
{
  "type": "source",
  "id": "s41"
}
```

The most consistent thread across the positive reports is a flu-like reaction in the first days, which users describe as the immune system waking up.

```widget
{
  "type": "source",
  "id": "s14"
}
```

The negative reports describe the same reaction without the recovery on the other side of it.

```widget
{
  "type": "source",
  "id": "s63"
}
```

```widget
{
  "type": "source",
  "id": "s37"
}
```

```widget
{
  "type": "source",
  "id": "s13"
}
```

Two reports concern measured markers rather than symptoms, in the same condition, and they disagree.

```widget
{
  "type": "source",
  "id": "s38"
}
```

```widget
{
  "type": "source",
  "id": "s59"
}
```

One comment states the risk in exactly the terms the mechanism implies.

```widget
{
  "type": "source",
  "id": "s77"
}
```

And one describes the physical failure mode that FDA's warning is about.

```widget
{
  "type": "source",
  "id": "s84"
}
```

## Proven, unproven, unknown

| Status | Claim |
|---|---|
| Proven | Approved as thymalfasin in roughly 35 countries for hepatitis B, hepatitis C and vaccine adjuvant use |
| Proven | Not approved in the United States or the European Union; no Drugs@FDA entry and no FDA label |
| Proven | Listed in FDA's "nominated but withdrawn" bulk-substances table, not in Category 2, and on neither the 503A nor the 503B bulks list |
| Proven | Acts through TLR9/MyD88/IRF7 on plasmacytoid dendritic cells; the effect is abolished in TLR9-deficient mice |
| Proven | Raises CD4+ percentage by 4.53 points and the CD4+/CD8+ ratio by 0.42 in critically ill humans |
| Proven | Peak serum at about 2 hours, elimination half-life about 2 hours, 31–60% urinary recovery |
| Proven | Sustained virological response advantage in chronic hepatitis B monotherapy, OR 2.87 (1.58–5.22) |
| Proven | Met the European regulator's antibody-response criteria as an influenza vaccine adjuvant in haemodialysis patients where vaccine alone did not |
| Proven | No mortality benefit in sepsis in a 1,106-patient placebo-controlled phase 3 |
| Proven | No reduction in infected pancreatic necrosis in a 508-patient placebo-controlled trial |
| Proven | Drug-related adverse events under 1% across indications in the licensed record, predominantly injection-site discomfort |
| Unproven | Any benefit in post-viral fatigue, chronic fatigue, MCAS, or any autoimmune condition — no completed randomised trial exists |
| Unproven | Benefit in COVID-19. Three observational studies, three different answers, one of them harm |
| Unproven | Whether the pancreatitis lymphocyte-count subgroup effect survives prospective testing |
| Unproven | Whether it improves disease-free survival in colorectal cancer; that trial reads out in 2027 |
| Unknown | The outcome of two completed phase 3 hepatitis C trials totalling 1,052 patients, never reported |
| Unknown | Any effect on tendon, ligament, disc, muscle or joint tissue. No model, no trial, no mechanism |
| Unknown | The correct dose for an outpatient with no diagnosed immune deficiency |
| Unknown | Whether grey-market material matches the pharmaceutical product that generated the safety record |

*Thymosin alpha-1 is not an approved drug in the United States and is not lawfully available there through the bulk-compounding pathways. Nothing here is a dosing or treatment recommendation.*

The sibling objects for this page, each one inspectable on its own terms:

![[kpv]]

![[ghk-cu]]

![[bpc-157]]

![[dsip]]

![[tb-500]]

## Facts

```json
{
  "converted_from": "markdown",
  "original_updated": "2026-08-04T20:47:55.530Z",
  "register": "essay",
  "category": null
}
```

## Sources

1. [Thymosin alpha 1: A comprehensive review of the literature](https://pmc.ncbi.nlm.nih.gov/articles/PMC7747025/) — “Thymosin alpha 1 is a peptide naturally occurring in the thymus that has long been recognized for modifying, enhancing, and restoring immune function.” (sha256 69ae2ec6dce0f41b)
2. [Immune Modulation with Thymosin Alpha 1 Treatment](https://pubmed.ncbi.nlm.nih.gov/27450734/) — “Thymosin alpha 1 (Ta1) is a peptide originally isolated from thymic tissue as the compound responsible for restoring immune function to thymectomized mice.” (sha256 8ecd71b1d34b2eb5)
3. [Comprehensive Review of the Safety and Efficacy of Thymosin Alpha 1 in Human Clinical Trials](https://pubmed.ncbi.nlm.nih.gov/38308608/) — “This study aims to assess the safety and efficacy of Thymosin Alpha 1 (Tα1) through a comprehensive narrative review of clinical studies involving over 11 000 human subjects in more than 30 trials.” (sha256 2bb7d5ee0a9a69f6)
4. [The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial](https://www.bmj.com/content/388/bmj-2024-082583) — “This trial found no clear evidence to suggest that thymosin α1 decreases 28 day all cause mortality in adults with sepsis.” (sha256 1d2c8b4989808eef)
5. [Phenotypic drug discovery: a case for thymosin alpha-1](https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2024.1388959/full) — “This article explores the experiences of researchers testing the effect of a thymic peptide hormone, thymosin alpha-1, in preclinical and clinical settings.” (sha256 19707f07a6ae1344)
6. [Thymalfasin (Thymosin Alpha 1; Ta1) as an Enhancer of Vaccine Response Among Older Adults Receiving Booster Doses of COVID-19 Vaccine](https://clinicaltrials.gov/study/NCT06821100) — “This research study will test the safety and possible harms of Ta1 when it is given to people at different dose levels before COVID-19 vaccination.” (sha256 d0dba429367c75bb)
7. [Thymosin alpha 1 alleviates inflammation and prevents infection in patients with severe acute pancreatitis through immune regulation: a systematic review and meta-analysis](https://pubmed.ncbi.nlm.nih.gov/40599771/) — “Thymosin alpha 1 (Tα1) is an important immunomodulatory agent in clinical practice, but there is a lack evidence to prove its effectiveness in improving the condition of SAP patients.” (sha256 e6e7b77fb1fdafda)
8. [5 Years Long Covid - Thymosin Alpha 1 Peptide - WOW!](https://www.reddit.com/r/covidlonghaulers/comments/1r5ekd8/5_years_long_covid_thymosin_alpha_1_peptide_wow/) — “I am now testing Thymosin Alpha 1 Peptide and I have to say WOW! This peptide brings me back to life.” (sha256 6b1862cdfa35eea6)
9. [Aging and Thymosin Alpha-1](https://www.mdpi.com/1422-0067/26/23/11470) — “Preclinical and clinical studies show that Tα1 can improve vaccine response in the elderly and mitigate immunosenescence.” (sha256 d5f11fb073f9b94f)
10. [Thymosin Alpha 1 Combined With Anti-PD-1 Monoclonal Antibody in Elderly Patients With Advanced Melanoma](https://clinicaltrials.gov/study/NCT07644897) — “Primary Objective: To evaluate the effectiveness of Thymosin Alpha-1 combined with PD-1 monoclonal antibody in elderly patients with advanced melanoma .” (sha256 a2b24476bb1a398a)
11. [Thymosin Alpha-1 Peptide: Benefits and Safety [2026]](https://www.innerbody.com/thymosin-alpha-1-peptide) — “In contrast to those findings, a placebo-controlled trial from early 2025 with over 1,000 subjects found “no clear evidence” that TA-1 decreased 28-day all-cause mortality in adults with sepsis.” (sha256 ac4a4cf0074337d4)
12. [Autoimmune Peptides: Just Hype? (Thymosin Alpha-1 ...](https://www.youtube.com/shorts/_3M2gu4kG68) — “Thymosin Alpha-1 helps recalibrate immune function so your body stops attacking itself while still defending against infections.” (sha256 1903f40318a67c52)
13. [be careful about thymosin alpha-1 : r/cfs](https://www.reddit.com/r/cfs/comments/1nl65vu/be_careful_about_thymosin_alpha1/) — “I am having the same problems with TA-1 I just connected the dots after 2 weeks of being on TA-1 my lymph nodes are swollen in my neck ...” (sha256 44e7102ef2f9ca59)
14. [Anyone get side effects/an immune reaction to Thymosin- ...](https://www.reddit.com/r/covidlonghaulers/comments/1pbotcz/anyone_get_side_effectsan_immune_reaction_to/) — “Im 2 weeks into TA-1 , its working as expected. Immune activation/rebalancing - clearing out virus/viral debris my body was unable to deal with before (Feels like a bad cold/minor flu).” (sha256 0e6bac5d6abb4117)
15. [A Complete Guide for Thymosin Alpha 1](https://www.reddit.com/r/Ameano_Peptides/comments/1ojbasq/a_complete_guide_for_thymosin_alpha_1/) — “I have been experimenting with ta1 and vip for a few weeks for some really bad eczema and doing a similar protocol. my eczema seems to respond really well to ta1...” (sha256 a85c455569386b3e)
16. [Thymosin Alpha 1 (Tα1) has anyone seen any studies or ...](https://www.reddit.com/r/covidlonghaulers/comments/1l2k4tj/thymosin_alpha1_t%CE%B11_has_anyone_seen_any_studies/) — “I just stated my ta-1 about two weeks ago and I can confirm I have felt the benefits majorly. Clearer head, heightened energy, just the ...” (sha256 6fa2764789c9fd3b)
17. [Peptide called Thymosin Alpha 1 is resolving my MCAS](https://www.reddit.com/r/MCAS/comments/1mcx0o3/peptide_called_thymosin_alpha_1_is_resolving_my/) — “TA-1 works when I use it! But it doesn't have a noticeable benefit when I'm not using it.” (sha256 83ad14bfeb231aaa)
18. [The Superhuman Immune System Peptide Big Pharma Wants BANNED](https://x.com/BowTiedUM/status/1760474750730568092) — “I knew I struck gold when I caught a cold, took a 2mg shot, and woke up the next day feeling GREAT. My cough, runny nose, and body aches: GONE” (sha256 1bdf644e60830f61)
19. [Megadose experience with Thymosin Alpha 1](https://x.com/jessicaalanas/status/1755232184317649040) — “I took a megadose of Thymosin Alpha 1 peptide for 3 days in a row. By day 3, I was so sick I could not go outside. Today, I woke up and I feel significantly *stronger* than before.” (sha256 1c0fda619995fa46)
20. [Thymalfasin (Thymosin Alpha 1) to Treat COVID-19 Infection](https://clinicaltrials.gov/study/NCT04487444) — “A course of Ta1 administered to hospitalized individuals with COVID-19 infection and lymphocytopenia will improve the time to recovery (primary objective) and ...” (sha256 0ae1a8a59f39489d)
21. [Thymosin alpha 1 alleviates inflammation and prevents infection in patients with severe acute pancreatitis through immune regulation: a systematic review and meta-analysis](https://pmc.ncbi.nlm.nih.gov/articles/PMC12208829/) — “Five randomized controlled trials comprising 706 patients with SAP were included.” (sha256 6bdb40c8d59f5e22)
22. [The Immunomodulatory Activity of Thymosin Alpha 1 on Tumor Cell Lines and Distinct Immune Cell Subsets](https://pubmed.ncbi.nlm.nih.gov/40955371/) — “The Immunomodulatory Activity of Thymosin Alpha 1 on Tumor Cell Lines and Distinct Immune Cell Subsets. Onco Targets Ther. 2025 Sep 10:18:995-1012.” (sha256 f4fa116527f4facc)
23. [Indications for an antidepressive effect of thymosin alpha-1 in a small open-label proof of concept study in common variable immune deficiency](https://pubmed.ncbi.nlm.nih.gov/39867848/) — “Indications for an antidepressive effect of thymosin alpha-1 in a small open-label proof of concept study in common variable immune deficiency.” (sha256 e7f185d979391c1b)
24. [Peptide for alopecia: Thymosin Alpha 1 as an Alternative to ...](https://www.reddit.com/r/HairlossResearch/comments/1rgcn3a/peptide_for_alopecia_thymosin_alpha_1_as_an/) — “TA1 is taken to suppress inflammation caused by the immune system. There is no clinical data that shows TA1 can heal your alopecia but it sounds promising.” (sha256 09ae5b852419fea7)
25. [Thymosin Alpha-1 Complete Guide: The Immune Peptide ...](https://www.reddit.com/r/Biohack_Blueprint/comments/1thd0od/thymosin_alpha1_complete_guide_the_immune_peptide/) — “Thymosin Alpha-1 modulates immune function in multiple ways: T-cell maturation and function.” (sha256 24cca77138a90494)
26. [X post on Thymosin Alpha 1](https://x.com/RickWingfield5/status/2071331718015918545) — “One "immune peptides" out there is Thymosin ALPHA 1. It is approved in over 40 countries.” (sha256 8b678f94d4b56715)
27. [Efficacy of thymosin α1 for sepsis: a systematic review and meta-analysis of randomized controlled trials](https://pubmed.ncbi.nlm.nih.gov/40969554/) — “Tα1 has the potential to decrease 28-day mortality rates in patients with sepsis; however, it is crucial to recognize that its efficacy differs among various subgroups. These observations underscore the significance of personalized immunotherapy strategies in forthcoming clinical trials.” (sha256 cf80c537ff2af418)
28. [Thymosin Alpha-1 (Zadaxin): A Thymic Peptide and Toll-Like Receptor Signaling Modulator](https://superpower.com/guides/thymosin-alpha-1) — “Thymosin alpha-1 is a 28-amino-acid thymic peptide approved as Zadaxin in more than 35 countries for chronic hepatitis B but not FDA-approved in the US. ... As of April 2026, thymosin alpha-1 is not FDA-approved in the United States. It is approved internationally under the brand name Zadaxin for chronic hepatitis B in more than 35 countries, including China and Italy. In the US, it holds FDA 503A Category 2 status following the February 2026 reclassification.” (sha256 174ed1807ca03072)
29. [Thymosin alpha 1 peptide?](https://www.reddit.com/r/ankylosingspondylitis/comments/1rzhnmd/thymosin_alpha_1_peptide/) — “The peptide thymosin alpha 1 has been shown to be able retrain the immune system. Ankylosing is an autoimmune disorder. It helps heal the gut but also helps ... Ok I have tried this peptide.” (sha256 f7107042dd7969b8)
30. [Thymosin Alpha-1 guide immune support, dosing, and ...](https://www.reddit.com/r/NTNPerformance/comments/1sx69j7/thymosin_alpha1_guide_immune_support_dosing_and/) — “Thymosin Alpha-1 guide immune support, dosing , It helps regulate immune response. Its been studied in hepatitis B and C” (sha256 97357da829d793f2)
31. [IL-15 Plus Thymosin α1 Reduces Senescent Hepatic CD8+ T Cells and Enhances Antitumor Immunity in Hepatocellular Carcinoma](https://pubmed.ncbi.nlm.nih.gov/41883056) — “Combined IL-15 and Tα1 therapy reverses CD8 + T cell senescence and enhances antitumor immunity in HCC through suppression of the phosphatidylinositol ...” (sha256 38866b08841112bf)
32. [Age-related thymic involution: Mechanistic insights and rejuvenating approaches to restore immune function](https://pmc.ncbi.nlm.nih.gov/articles/PMC12904209/) — “Thymosin α1 is used to treat some chronic viral infections , such as hepatitis B and C, as an immunomodulator (125). In a recent retrospective analysis of patients with COVID-19 treated with thymosin α, this hormone enhanced T cell production...” (sha256 b233bde3a7a3127e)
33. [Thymosin alpha 1 alleviates inflammation and prevents infection in patients with severe acute pancreatitis through immune regulation: a systematic review and meta-analysis](https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2025.1571456/full) — “Five randomized controlled trials comprising 706 patients with SAP were included. The results indicated that Tα1 could increase the percentages of CD4 + cells (MD=4.53, 95%CI [3.02, 6.04], P<0.00001) and improve the CD4 + /CD8 + ratio...” (sha256 2cabaf8167cf971a)
34. [What Is Thymosin Alpha 1? How It Works and What the Clinical Data Shows](https://www.youtube.com/watch?v=d_ZW05Wrm_s) — “We cover: 🛡️ What Thymosin Alpha-1 is and how it regulates your immune system Why it's ideal for inflammation, immune burnout, and chronic ...” (sha256 01da3f04aabb4fe3)
35. [Has anyone tried Thymosin Alpha 1 for Long COVID?](https://www.reddit.com/r/LongCovidTrials/comments/1opyifn/has_anyone_tried_thymosin_alpha_1_for_long_covid/) — “Hi all, Our team is curious if anyone out there has tried the peptide Thymosin Alpha 1 for Long COVID. We’re asking for research purposes (not endorsing ...” (sha256 0a73fb7398923f2c)
36. [Aging and Thymosin Alpha-1](https://pmc.ncbi.nlm.nih.gov/articles/PMC12692621/) — “Thymosin alpha-1 (Tα1), a peptide hormone produced by the thymus, exhibits potent immunomodulatory, anti-inflammatory, and antioxidant properties.” (sha256 f39633c2df693056)
37. [Thymosin-alpha 1 ??](https://www.reddit.com/r/CIRS/comments/1ncxx31/thymosinalpha_1/) — “I actually tried it back in October and it sent me into the worst flare I’ve had in 4 years. Felt awful and took me almost 2 full months to recover.” (sha256 128ce7b93ce84092)
38. [Peptides](https://www.reddit.com/r/Hashimotos/comments/1lped2z/peptides/) — “I tried TA-1 for 8 weeks and it increased my TPO antibodies.” (sha256 efa9843fc62d464e)
39. [Thymosin-alpha 1 ??](https://www.reddit.com/r/CIRS/comments/1ncxx31/thymosinalpha_1/) — “Each herx reaction was slightly different but the first one, I felt “classicly sick”, like how normal people feel when they get the flu... Then after that they started to feel a bit more similar, usually severe fatigue plus normal viral symptoms. ... once I stabilize at each dose increase, I feel like I get about 2-3% of my life back.” (sha256 e238ee2636bdac0e)
40. [X post by @CaneGrrl](https://x.com/CaneGrrl/status/2068318610662072812) — “Anyone else experience sleep benefits with Thymosin Alpha-1? Could be a coincidence but my REM and deep sleep have gone up every night I’ve take it (which is only 3 so far, but still…)” (sha256 32383818bb5c25ab)
41. [X post by @quardoqu](https://x.com/quardoqu/status/2060338402189353350) — “My top Long Covid treatments so far after six years in order of effectiveness out of a 100+: 1. LDN ... 2. Subq TA-1 (Thymosin Alpha 1) ...” (sha256 3d6c0c1c19df711d)
42. [X post by @quardoqu](https://x.com/quardoqu/status/2042676733057405170) — “Any idea why Thymosin Alpha 1 takes my Long Covid symptoms away for 48 hours?” (sha256 e733c7922abe1142)
43. [Efficacy of thymosin α1 for sepsis: a systematic review and meta-analysis](https://pmc.ncbi.nlm.nih.gov/articles/PMC12440967/) — “In this updated meta-analysis, we found that thymosin alpha 1 (Tα1) may reduce 28-day mortality in patients with sepsis compared to the control group” (sha256 27f522fa32ac129c)
44. [A Case Report of a Multisystemic Immune‐Related Adverse Event Induced by Thymosin Alpha‐1](https://pmc.ncbi.nlm.nih.gov/articles/PMC12883329/) — “Thymosin alpha‐1 (Tα1 ) is an immunomodulatory peptide known to play critical roles in T cell maturity and differentiation” (sha256 6534a308ae17cc9c)
45. [Expert Consensus on the Clinical Application of Thymosin Alpha 1 in Infectious Diseases and Critical Care Medicine](https://journals.lww.com/imd/fulltext/2025/06000/expert_consensus_on_the_clinical_application_of.2.aspx) — “10 recommendations on the application of Tα1 in treatment of liver diseases, viral infections, bacterial infections and critical illnesses.” (sha256 9810e2352c5496d0)
46. [Thymosin alpha-1–enhanced PRaG regimen: A novel approach to boosting immune dynamics and therapeutic efficacy in advanced solid tumors](https://ascopubs.org/doi/10.1200/JCO.2025.43.16_suppl.e14606) — “Thymosin Alpha 1 (Tα-1), a well-established immunomodulator, is known to protect lymphocytes, reduce lymphocytopenia during radiotherapy, and enhance T lymphocytes.” (sha256 9a09c535cf580f2d)
47. [Thymalin and Thymosin Alpha-1 Both Target the Thymus](https://www.reddit.com/r/IonPeptideGuide/comments/1tp86o7/thymalin_and_thymosin_alpha1_both_target_the/) — “Thymosin Alpha-1 is a single defined 28-amino acid peptide sequence. It has an approved pharmaceutical form - Zadaxin - used clinically in over 35 countries” (sha256 27de5c908c012a5e)
48. [GELİŞEN PEPTİD NOMENKLATÜRÜ](https://x.com/dogalyasalar/status/2067307286138143114) — “○ Bağışıklık Modülasyonu — Thymosin Alpha-1 (TA1) — Thymosin Beta-4 (TB-500) — LL-37 — KPV” (sha256 b265622dbb9e1e7c)
49. [IL-15 Plus Thymosin α1 Reduces Senescent Hepatic CD8+ ...](https://pubmed.ncbi.nlm.nih.gov/41883056/) — “Conclusions: Combined IL-15 and Tα1 therapy reverses CD8 + T cell senescence and enhances antitumor immunity in HCC through suppression of the ...” (sha256 bdf69bc47282f48f)
50. [Long-term Prognosis of Patients With Sepsis After ...](https://clinicaltrials.gov/study/NCT04901104) — “Current clinical studies of thymosin α1 for sepsis have focused on short-term outcomes (28-day or 90-day mortality), and lack of clinical data on long-term ...” (sha256 d5a5a1166dee5e77)
51. [Thymosin α1 Elevates Lymphocyte Counts and Improves ...](https://pubmed.ncbi.nlm.nih.gov/41293232/) — “Tα1 treatment for 7 days significantly increased the median counts of peripheral blood total T cells (422.5/μL to 614.0 /μL, P<0.001), CD4 + T ...” (sha256 5b68a26b86102e45)
52. [Protective Effect of Ulinastatin and Thymosin α1 Against ...](https://clinicaltrials.gov/study/NCT06966687) — “This study was designed to test the hypothesis that the administration of Ulinastatin and Thymosin α1 during the acute phase of AAS will result in a reduced ...” (sha256 22b7e0f31ce0879a)
53. [The efficacy and safety of thymosin alpha-1 combined with ...](https://pubmed.ncbi.nlm.nih.gov/40263352/) — “Thymosin α-1 combined with lenvatinib plus sintilimab is an effective and safe therapeutic regimen in unresectable hepatocellular carcinoma.” (sha256 968cc73fc251e8c8)
54. [Thymosin Alpha-1: Transforming Immunotherapy for ...](https://www.youtube.com/watch?v=HgcNS3pkeyE) — “patient considerations associated with thymosin alpha 1 additionally we will review three clinical case studies to” (sha256 c35580b649fff1c8)
55. [Thymosin Alpha 1 - experiences and anecdotes. A treatment for severe allergies?](https://www.evolutionary.org/forums/threads/thymosin-alpha-1-experiences-and-anecdotes-a-treatment-for-severe-allergies.109790/) — “I love TA1 and cycle it twice a year. In spring and fall. I'll mix it in other times if I'm feeling off. I personally use it to help my immune responses to both spring and fall allergies. It's worked well to have a lower response to the allergens.” (sha256 448c5715dafb1d5a)
56. [Thymosin Alpha 1 - experiences and anecdotes. A treatment for severe allergies?](https://www.evolutionary.org/forums/threads/thymosin-alpha-1-experiences-and-anecdotes-a-treatment-for-severe-allergies.109790/) — “I put a mate onto Regenex as his eldest kid had Harishmotos disease and jumped on TA1 and apparently working well.” (sha256 e6daadb7ab56b7b1)
57. [Thymosin Alpha-1: The Immune-Boosting Peptide You Should Know About](https://www.ozarkholisticcenter.com/post/thymosin-alpha-1-the-immune-boosting-peptide-you-should-know-about) — “One patient who had struggled with recurrent respiratory infections told us, “It feels like my body finally has its army back.”” (sha256 80d818ff7e395993)
58. [Best peptides and brands for MCAS ? BPC-157, KPV and Thymosin / Thymogen ?](https://www.reddit.com/r/MCAS/comments/1lki5p2/best_peptides_and_brands_for_mcas_bpc157_kpv_and/) — “Don't use BCP for treating Mast Cell, honestly, for me thymosin-1 microdosing worked the best. Hard to get your hands on it, but a lab called Next Gen Peps was where I ended up at, pretty reliable & its a USA based.” (sha256 925e9d36f2176e4c)
59. [Peptides? Anyone taking these?](https://www.reddit.com/r/Hashimotos/comments/1sylqox/peptides_anyone_taking_these/) — “I will be testing my TPO at the 6 week mark in 2 weeks for TA-1. I was at 97 at the start, and I had actually done a single vial of 1 mg a day for 10 days and my Tpo had dropped about 10 points so I am hoping that was the cause and I can bring it down with a longer protocol.” (sha256 016c5baa1877a8a4)
60. [What resolved my chronic fatigue - 5 years later](https://www.reddit.com/r/chronicfatigue/comments/1j2z1az/what_resolved_my_chronic_fatigue_5_years_later/) — “Peptides: I have started taking Thymosin Alpha 1, Thymosin Beta 4, Semax and Selank. ... Thymosin Alpha 1 is an immune modulator so it helps improve the immune system. It also has anti inflammatory effects.” (sha256 a7706b33d0edcf05)
61. [Thymosin Alpha 1](https://www.reddit.com/r/Peptides_for_Women/comments/1gy3d3a/thymosin_alpha_1/) — “Within an hour felt significantly better, I mean total package of energy and good mood. ... Inflammation has been decreasing and histamine reaction is definitely getting better. ... within an hour I could do full range squats. Walking down stairs with full flexing and no pain. I’ve lost 3.5lbs of inflammation in 3 days.” (sha256 796d59435c94ebd3)
62. [Thymosin Alpha 1](https://www.reddit.com/r/Peptides_for_Women/comments/1gy3d3a/thymosin_alpha_1/) — “TA1 is one of my favorite peptides! I’m allergic to animals but I love them. Was wrestling around w my brothers dog last night ... and left without washing my hands and did not wheeze, cough, choke or blow my nose. ... my first time, within 2 hours I can only compare my reaction to Covid like symptoms. ... lasted about eight hours.” (sha256 8cbff1b441c6a0b3)
63. [Those who tried peptides - permanent shift in baseline?](https://www.reddit.com/r/covidlonghaulers/comments/1peun65/those_who_tried_peptides_permanent_shift_in/) — “Thymosin-Alpha-1 _destroyed me_ - one 0.5mg injection and within 12 hours I had a severe flu-like immune reaction (fever, diarrhea, pins and needles, the works). The immune reaction continued the next day as well, and even after subsiding, I'm still crashed from it five days later - in the 70s whereas previously I was in the high 80s.” (sha256 b44d4171b121804e)
64. [Those who tried peptides - permanent shift in baseline?](https://www.reddit.com/r/covidlonghaulers/comments/1peun65/those_who_tried_peptides_permanent_shift_in/) — “Thymosin alpha makes me feel acutely ill for a day or two.” (sha256 44cc02128d082839)
65. [Peptide for alopecia: Thymosin Alpha 1 as an Alternative to JAK Inhibitors](https://www.reddit.com/r/tressless/comments/1rgcm86/peptide_for_alopecia_thymosin_alpha_1_as_an/) — “Hair loss due to Long Covid here, with TA-1 the hairs grew back.” (sha256 b75fcfb77e1c2700)
66. [Thymosin Alpha 1 and Peptides for LC Discussed on Huberman Lab](https://www.reddit.com/r/covidlonghaulers/comments/1g2y1yx/thymosin_alpha_1_and_peptides_for_lc_discussed_on/) — “ME/CFS here - I’ve used TA1 and Thymulin with great success. I’ve had to increase the dose and I can still overdo it and cause PEM and I have to take it daily or the benefit is lost but….it absolutely provides a lift in energy and brain fog and functionality.” (sha256 1e4b64320dde8aea)
67. [Thymosin Alpha 1 and Peptides for LC Discussed on Huberman Lab](https://www.reddit.com/r/covidlonghaulers/comments/1g2y1yx/thymosin_alpha_1_and_peptides_for_lc_discussed_on/) — “Nice! I just did a cycle which caused a lot of side effects. I thought I'd made a huge mistake, but once I stopped taking it, I found my baseline came back higher.” (sha256 fbf9bc8ee7a75702)
68. [X post by @thecoercednurse](https://x.com/thecoercednurse/status/2070187778584047692) — “It helped to stop the progression of my immune/cardiovascular/respiratory failure. Decreased the debilitating muscle spasms. Improved my ADL function. Kept my autonomic swings more level. Essentially stopped me from needing to choose hospice/palliative care as my only option.” (sha256 b38a91910f7c7b74)
69. [X post by @squarian24](https://x.com/squarian24/status/2070542926623490303) — “I’m being very serious. There’s minimal side effects, no long term effects have been shown after a near decade of studies, and it works.” (sha256 ed30c1b0462728fd)
70. [Thymosin Alpha 1](https://www.reddit.com/r/pancreaticcancer/comments/x71x4v/thymosin_alpha_1/) — “I did find some pre clinical evidence that Thymosin Alpha 1 was protective against opportunistic infection due to suppression from 5-flurouracil.” (sha256 79b4f486a46b5e01)
71. [Zadaxin Thymosin alpha-1(TA-1) peptide to help slow muscle recovery?](https://www.reddit.com/r/Hashimotos/comments/1sxdk9m/zadaxin_thymosin_alpha1ta1_peptide_to_help_slow/) — “Thymosin Alpha 1 is more for immunoregulation, ie those pesky T cells.” (sha256 a9ec1a6ca0be34da)
72. [Thymosin Alpha-1](https://www.reddit.com/r/AutoImmuneProtocol/comments/1rzrql8/thymosin_alpha1/) — “Anyone has tried Thymosin Alpha-1 for Graves autoimmune? If not, what worked for you to drop your antibodies?” (sha256 d91516f450602297)
73. [Thymosin Alpha 1, LDN, or GLPS? or all three?](https://www.reddit.com/r/endometriosis/comments/1s8dkwf/thymosin_alpha_1_ldn_or_glps_or_all_three/) — “My dr wants me on TA1 for chronic EBV as well and heard it might possibly help immune system fight off endo.” (sha256 1fa18b6edc6740fc)
74. [Thymosin Alpha-1 testing](https://x.com/BhavanChand/status/2071648123559288889) — “My kids caught cold again 3 days ago My mother also caught cold from them It didn't spread to me yet and I didn't take my Thymosin Alpha -1 Testing if the previous doses are working or not” (sha256 cdf0bea9475260d1)
75. [Thymosin Alpha-1 for sinusitis](https://x.com/biotides/status/2071620162831159366) — “For someone who suffers from sinusitis, one of the best remedies I’ve used is Thymosin Alpha-1. I use it as needed. But it almost immediately opens the sinuses up and cleans out the gunk. Same with the throat.” (sha256 b87bba6837e77279)
76. [RNA seq data with TA1](https://x.com/DuaneStorey/status/2071544627635581270) — “Day 0 meds: baseline, Thymosin Alpha 1 for a few days. ... Good news is a substantial amount of my out of range genes went back into range on day 42.” (sha256 8eef6d379dc59f0c)
77. [Thymosin Alpha 1](https://www.reddit.com/r/smallfiberneuropathy/comments/1phisi1/thymosin_alpha_1/) — “It's a risky gamble imo. There is a small subset of SFN patients who I would expect to get modestly better from Ta1, with the rest either getting no benefit or even feeling _worse_. You don't want to jack up T cell activity if T cell activity is already problematic.” (sha256 2b7c150650632a5f)
78. [Thymosin Alpha 1](https://www.reddit.com/r/smallfiberneuropathy/comments/1phisi1/thymosin_alpha_1/) — “I just started! Haven’t seen any results or had any relief yet but I will keep you posted!” (sha256 08179c0e4fb7731f)
79. [Thymosin alpha 1 daily vs twice weekly administration](https://www.reddit.com/r/Immunology/comments/q6bgrz/thymosin_alpha_1_daily_vs_twice_weekly/) — “I basically get more ill for a few days every time I take the TA1. So it’s a bit of a hinderance to general work and life stuff. I might try lower doses to see if that is easier to handle.” (sha256 a8c9fbd8e8964af1)
80. [Thymosin alpha 1 daily vs twice weekly administration](https://www.reddit.com/r/Immunology/comments/q6bgrz/thymosin_alpha_1_daily_vs_twice_weekly/) — “I’m thinking of doing 2-3x a week around 800mcg after starting at 300mcg to see if I react to it. I’ll also run TB-500 for healing.” (sha256 efe1c38bd3e510fe)
81. [Thymosin Alpha-1: The Immune System Peptide Nobody Talks About](https://www.reddit.com/r/PeptideProgress/comments/1s62nmn/thymosin_alpha1_the_immune_system_peptide_nobody/) — “The people who tend to benefit most from Thymosin Alpha - 1 are those dealing with frequent illness, slow recovery from infections, chronic fatigue, and autoimmune issues.” (sha256 1f95ef9850e67556)
82. [Thymosin Alpha-1 🏥 Immune System Peptide Explained | T-Cell Activation, Inflammation Control & Recovery Support (Complete 2025 Research Guide)](https://www.reddit.com/r/USPeptides/comments/1p43fnb/thymosin_alpha1_immune_system_peptide_explained/) — “TA1 isn’t one of those “immune booster” things. It doesn’t just crank your immune system up. It’s more like helping it work normally again, especially after burnout or chronic stress.” (sha256 42b1eec89f7acca7)
83. [Thymosin Alpha-1 🏥 Immune System Peptide Explained | T-Cell Activation, Inflammation Control & Recovery Support (Complete 2025 Research Guide)](https://www.reddit.com/r/USPeptides/comments/1p43fnb/thymosin_alpha1_immune_system_peptide_explained/) — “I got some blood work done and it recommended I take TA1 for chronic inflammation. ... TA-1 tends to help people. ... You feel less inflamed or “worn down”, you bounce back faster when you’re tired or sick.” (sha256 0157fa37bad006cb)
84. [Ta1 Cloudy at Reconstitution](https://www.reddit.com/r/Peptides/comments/1s5cv2z/ta1_cloudy_at_reconstitution/) — “I have tried two different vials of Thymosin Alpha 1 from the same source and both are cloudy with suspended ...” (sha256 7e7bf38f9e624414)
85. [LL37 & Thymosin Alpha Review](https://www.reddit.com/r/Peptides/comments/1hhefnv/ll37_thymosin_alpha_review/) — “I have begun a LL37 and Thymosin Alpha cycle, this time for the exact purpose of healing the body in all the ways these peptides are said to do.” (sha256 1e817090c0e5060d)
86. [Thymosin Alpha 1: Is there a way to check from bloodwork ...](https://www.reddit.com/r/Peptides/comments/1d2d4s2/thymosin_alpha_1_is_there_a_way_to_check_from/) — “I ordered some Thymosin Alpha 1 recently and will be trying it soon for the first time. I'll be using it to try and treat a chronic ...” (sha256 f0d7b33904c030f0)
87. [The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial (Crit Care 2013; PMID 23327199; NCT00711620)](https://pubmed.ncbi.nlm.nih.gov/23327199/) — “Greater improvement of mHLA-DR was observed in the Ta1 group on day 3 (mean difference 3.9%, 95% CI 0.2 to 7.6%, P = 0.037) and day 7 (5.8%, 95% CI 1.0 to 10.5%, P = 0.017). No serious drug-related adverse event was recorded.” (sha256 530fa6d829a786c9)
88. [The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial (Crit Care 2013; PMID 23327199; NCT00711620)](https://pubmed.ncbi.nlm.nih.gov/23327199/) — “The mortalities from any cause within 28 days in the Ta1 group and control group were 26.0% and 35.0% respectively with a marginal P value (nonstratified analysis, P = 0.062; log rank, P = 0.049)” (sha256 cc884970194ac469)
89. [The efficacy and safety of thymosin alpha1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial (BMJ 2025; PMID 39814420; NCT02867267)](https://pubmed.ncbi.nlm.nih.gov/39814420/) — “28 day all cause mortality occurred in 127 participants (23.4%) in the thymosin alpha1 group and 132 (24.1%) in the placebo group (hazard ratio 0.99, 95% confidence interval 0.77 to 1.27; P=0.93)” (sha256 e04d4210c31b348a)
90. [Immune enhancement in patients with predicted severe acute necrotising pancreatitis: a multicentre double-blind randomised controlled trial (TRACE, Intensive Care Med 2022; PMID 35713670; NCT02473406)](https://pubmed.ncbi.nlm.nih.gov/35713670/) — “40/254(15.7%) patients in the Ta1 group developed IPN compared with 46/254 patients (18.1%) in the placebo group (difference -2.4% [95% CI - 7.4 to 5.1%]; p = 0.48)” (sha256 5b204a1c761dd5f2)
91. [Association between pretreatment lymphocyte count and efficacy of immune-enhancing therapy in acute necrotising pancreatitis: post-hoc analysis of TRACE (EClinicalMedicine 2023; PMID 37007743)](https://pubmed.ncbi.nlm.nih.gov/37007743/) — “Within the subgroup of patients with baseline ALC>=0.8 x 10^9/L (n = 290), the Ta1 therapy significantly reduced the risk of IPN (covariate adjusted risk difference, -0.12; 95% CI, -0.21,-0.02; p = 0.015)” (sha256 c5dd0a716472cf46)
92. [Thymosin Alpha 1 Reduces the Mortality of Severe Coronavirus Disease 2019 by Restoration of Lymphocytopenia and Reversion of Exhausted T Cells (Clin Infect Dis 2020; PMID 32442287)](https://pubmed.ncbi.nlm.nih.gov/32442287/) — “Compared with the untreated group, Ta1 treatment significantly reduced the mortality of severe COVID-19 patients (11.11% vs 30.00%, P = .044)” (sha256 057fc802f06bd45e)
93. [Efficacy of Thymosin Alpha 1 in the Treatment of COVID-19: A Multicenter Cohort Study (Front Immunol 2021; PMID 34408744)](https://pubmed.ncbi.nlm.nih.gov/34408744/) — “After adjusting for confounding factors, Ta1 use was found to be significantly associated with a higher non-recovery rate than non-Ta1 use (OR 1.5, 95% CI 1.1-2.1, p = 0.028)” (sha256 4ee8d530ea1337a6)
94. [Efficacy Evaluation of Thymosin Alpha 1 in Non-severe Patients With COVID-19: A Retrospective Cohort Study Based on Propensity Score Matching (Front Med 2021; PMID 33968969)](https://pubmed.ncbi.nlm.nih.gov/33968969/) — “the Thymosin-alpha1 group had significantly shorter SARS-CoV-2 RNA shedding duration (13 vs. 16 days, p = 0.025) and hospital stay (14 vs. 18 days, p < 0.001)” (sha256 1b6c4d87607a2869)
95. [A Pilot Trial of Thymalfasin (Ta1) to Prevent COVID-19 Infection in Renal Dialysis Patients (NCT04428008, posted results)](https://clinicaltrials.gov/study/NCT04428008) — “Number of Participants With COVID-19 Infection: Active Arm 5, Control Arm 7. Deaths: Active Arm 3/91, Control Arm 7/98.” (sha256 bbd9094a370710b6)
96. [Phase II dose-ranging trial of dacarbazine plus interferon alpha plus thymosin alpha-1 in advanced metastatic melanoma (NCT00911443, posted results, n=488)](https://clinicaltrials.gov/study/NCT00911443) — “Overall Survival, months: DTIC+IFN+Ta1 6.4 mg 10.3; DTIC+Ta1 3.2 mg 9.3; DTIC+IFN+Ta1 1.6 mg 9.3; DTIC+IFN+Ta1 3.2 mg 8.6; DTIC+IFN alone 6.6” (sha256 5af6d076ed13f199)
97. [Phase III trial of thymosin alpha 1 plus peginterferon alfa-2a plus ribavirin in chronic hepatitis C non-responders (NCT01178996, n=552, completed 2009, no results posted)](https://clinicaltrials.gov/study/NCT01178996) — “Thymosin alpha 1 (Zadaxin) 1.6 mg/day, two times weekly in the morning, by subcutaneous injection for 48 weeks. Primary outcome: Sustained Virological Response (SVR) at Week 72.” (sha256 29d7bda91cb63627)
98. [Thymosin-alpha 1 as adjuvant treatment after radical resection of high-risk stage II and III colorectal cancer (NCT05086614, phase 3, 2500 planned, primary completion 2027)](https://clinicaltrials.gov/study/NCT05086614) — “Receive thymosin-alpha 1 1.6mg with subcutaneous injection, twice a week, for 6 months after radical resection. Primary outcome: 3-year disease-free survival rate.” (sha256 e8a2f2e9f9edea65)
99. [Thymosin-alpha 1 (Zadaxin) enhances the immunogenicity of an adjuvated pandemic H1N1v influenza vaccine (Focetria) in hemodialyzed patients: a pilot study (Vaccine 2012; PMID 22178096)](https://pubmed.ncbi.nlm.nih.gov/22178096/) — “The CHMP criteria were fully met in the groups treated with Vaccine+Thymosin alpha 1. No AE was found to be related to Thymosin alpha 1 nor to the Focetria vaccine.” (sha256 1d2cb678ca7bb4c6)
100. [Thymosin alpha1 activates the TLR9/MyD88/IRF7-dependent murine cytomegalovirus sensing for induction of anti-viral responses in vivo (Int Immunol 2007; PMID 17804687)](https://pubmed.ncbi.nlm.nih.gov/17804687/) — “The anti-viral effect of Talpha1 occurred through the activation of plasmacytoid DCs via the TLR9/myeloid differentiation primary response gene 88-dependent viral recognition sensing, leading to the activation of IFN regulatory factor 7” (sha256 6d5bae9ffcfb9ba9)
101. [Thymosin alpha1: an endogenous regulator of inflammation, immunity, and tolerance (Ann N Y Acad Sci 2007; PMID 17495242)](https://pubmed.ncbi.nlm.nih.gov/17495242/) — “Talpha1 primed DCs for antifungal Th1 resistance through Toll-like receptor (TLR)/MyD88-dependent signaling; activated plasmacytoid DCs via TLR9/MyD88-dependent viral recognition; induced indoleamine 2,3-dioxygenase activity in DCs, thus affecting tolerization toward self as well as microbial non-self-antigens” (sha256 a0773d121de9c956)
102. [Thymosin alpha1 and cancer: action on immune effector and tumor target cells (Ann N Y Acad Sci 2012; PMID 23045967)](https://pubmed.ncbi.nlm.nih.gov/23045967/) — “Ta1 has been shown to exert an immune modulatory activity on both T cell and natural killer cell maturation and to have an effect on functions of mature lymphocytes, including stimulating cytokine production and cytotoxic T lymphocyte-mediated cytotoxic responses” (sha256 6eabdcf84d40bfc8)
103. [FDA: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (page current as of 22 April 2026) - Thymosin-alpha 1 appears in the 'Bulk drug substances nominated but withdrawn' table](https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks) — “Compounded drugs containing thymosin-alpha-1 (Ta1) may pose significant risk for immunogenicity for certain routes of administration and may have complexities with regard to peptide-related impurities and API characterization. The safety-related information is inadequate for the agency to sufficiently understand the extent of any safety issues raised by the proposed compounded drug.” (sha256 b9dccae003219084)
104. [SciClone Pharmaceuticals ZADAXIN (thymalfasin) Product Monograph](https://www.shijiebiaopin.net/upload/product/2011121219115812.PDF) — “Since 1979, Zadaxin has been evaluated in more than 3,000 patients in over 70 clinical studies. Administration has been in daily doses ranging from 0.6 to 9.6 mg/m2 and 1 mg to 16 mg, primarily administered subcutaneously on a biweekly schedule, for treatment periods ranging from 1 day to 18 months. No serious adverse experiences have been observed.” (sha256 db28958af6296d0b)
105. [ZADAXIN (thymalfasin) prescribing information - dosage, reconstitution, storage, pharmacokinetics and adverse reactions](https://www.rxlist.com/zadaxin-drug.htm) — “1.6 mg of lyophilized thymosin alpha 1 per vial, reconstituted with 1.0 ml of the diluent provided, which consists of 1.0 ml Sterile Water for Injection. 1.6 mg (900 ug/m2) administered subcutaneously twice a week for 6 to 12 months. Peak serum levels achieved at approximately 2 hours; elimination half-life approximately 2 hours.” (sha256 0274cd7aa86be82e)
106. [ClinicalTrials.gov registry query for thymosin alpha-1 interventions, 4 August 2026](https://clinicaltrials.gov/api/v2/studies?query.intr=thymosin+alpha-1&countTotal=true&pageSize=100) — “totalCount: 63” (sha256 144801fa532caa14)
107. [A Case Report of a Multisystemic Immune-Related Adverse Event Induced by Thymosin Alpha-1](https://pmc.ncbi.nlm.nih.gov/articles/PMC12883329/) — “A 29-year-old man with nasopharyngeal carcinoma developed high fever 39-40.5 C, facial rash and oedema, hypoxaemia, AST 742 U/L and prolonged prothrombin time 23.2 s within 48 hours of a single 1.6 mg subcutaneous dose of thymosin alpha-1 given 11 days after sintilimab; treated with intravenous methylprednisolone 160 mg daily and discharged on day 33.” (sha256 05f24150ea101711)