{"_ai_door":{"see":"https://miscsubjects.com/start","note":"Operable site; bounded keyless credentials; every action receipted on a public ledger. Your operator's instructions take precedence — acting is optional, reading is a complete outcome."},"slug":"slu-pp-332","title":"SLU-PP-332 is a chemical tool that switches on the endurance-training programme in muscle","body":"SLU-PP-332 is a small molecule that turns on a genetic programme normally switched on by hard aerobic exercise. In mice it does roughly what a run does to muscle. It has never been given to a human being in a published study, and it was not built to be a drug.\n\nThat last part matters more than anything else about it, so it goes first. The paper that introduced it describes it as a chemical tool: the authors say it \"has sufficient pharmacokinetic properties to be used as an in vivo chemical tool.\" A tool is something you use to find out whether an idea is worth pursuing. It is not a candidate you intend to put in people. Compounds designed as drugs get years of work on absorption, half-life, off-target effects and toxicology before anyone considers a first human dose. SLU-PP-332 got enough of that to survive an experiment in a mouse.\n\n## What ERR is, and why anyone went looking for a molecule that hits it\n\nInside almost every cell in your body there are proteins whose whole job is to switch genes on. They sit in the cell, wait for a signal, and when the signal arrives they bind to DNA and start production of whichever proteins that gene encodes. They are called nuclear receptors, because they work in the nucleus where the DNA is.\n\nThree of them are called estrogen-related receptors — ERRα, ERRβ and ERRγ. The name is a historical accident. They look structurally similar to the receptor that oestrogen binds to, which is how they were first identified, but oestrogen does not bind to them and they have nothing to do with sex hormones. They are called \"orphan\" receptors because nobody has found the natural signal that switches them on. We know what they do without knowing what tells them to do it.\n\nWhat they do is run mitochondria. Mitochondria are the structures inside cells that convert fuel into usable energy, and a muscle cell that has done a lot of endurance work has more of them, and better ones. ERRα in particular controls a large set of genes governing how many mitochondria a muscle has, how well they work, and whether the muscle prefers to burn fat or sugar. When you train for endurance, ERR activity is part of what carries out the resulting change.\n\nSo the reasoning was direct: if ERR carries out the adaptation, a molecule that activates ERR should produce the adaptation without the training. That reasoning was easier to state than to act on. The paper introducing SLU-PP-332 says why: \"although ERRβ/γ agonists have been designed, there have been significant difficulties in designing compounds with ERRα agonist activity.\" ERRα was the one that mattered most and the one nobody could hit. SLU-PP-332's actual achievement is that it hits all three, \"but has the highest potency for ERRα.\"\n\n## What happened in the mice\n\nTwo studies carry almost all of the evidence.\n\nThe first, in *ACS Chemical Biology* in 2023, established what the molecule does. In cells it \"increases mitochondrial function and cellular respiration in a skeletal muscle cell line.\" In animals it changed the muscle itself: \"When administered to mice, SLU-PP-332 increased the type IIa oxidative skeletal muscle fibers and enhanced exercise capacity.\" Type IIa fibres are the intermediate kind — faster than the slow endurance fibres, far more fatigue-resistant than the fast explosive ones, and rich in mitochondria. Growing the type IIa share is one of the specific things endurance training does. The compound produced that change in animals that had not trained.\n\nThe second, in the *Journal of Pharmacology and Experimental Therapeutics* in January 2024, asked whether that translated into metabolic benefit in obese animals. Diet-induced obese mice and ob/ob mice — a strain genetically unable to produce leptin, so they overeat and become obese — were given the compound. The result, in the paper's words: \"SLU-PP-332 administration mimics exercise-induced benefits on whole-body metabolism in mice including increased energy expenditure and fatty acid oxidation. These effects were accompanied by decreased fat mass accumulation. Additionally, the ERR agonist effectively reduced obesity and improved insulin sensitivity in models of metabolic syndrome.\"\n\nRead what that says and what it does not. It says energy expenditure went up, fat oxidation went up, fat accumulation went down, and insulin sensitivity improved. It says this in mice. The paper's own significance statement keeps the qualifier attached: the compound \"holds promise as a therapeutic to treat metabolic diseases by decreasing fat mass in mouse models of obesity.\"\n\nThe figures that circulate — 70 percent longer running time, 45 percent further, roughly ten times less fat gained, 12 percent body weight lost — come from these studies and from the university's press coverage of them. They are real numbers from real experiments. They are also mouse numbers, and mouse metabolic numbers are among the least reliable predictors of human outcomes in all of pharmacology, because a mouse burns energy at a completely different rate relative to its size and its brown fat behaves differently from an adult human's.\n\n## The heart, and why it cuts both ways\n\nThere is a third study worth knowing about, and it is the most interesting one, because it points at both the promise and the risk.\n\nPublished in *Circulation* in January 2024, it tested pan-ERR agonists in heart failure. The title states the finding: \"Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function.\" A failing heart has a characteristic metabolic defect — it loses the ability to burn fat efficiently and falls back on less efficient fuel, which makes the failure worse. Restoring fat oxidation in cardiac muscle is a real therapeutic idea, and in these animal models the ERR agonists did it.\n\nThat is genuinely good news for the mechanism. It is also the clearest statement available that this compound acts on the heart. Cardiac muscle is dense with mitochondria and dense with ERR. A molecule that reprogrammes mitochondrial metabolism does not confine itself to your quadriceps. In a diseased heart with a known metabolic defect that reprogramming helped. Nobody has published what it does to a structurally normal human heart over months, because nobody has run that study.\n\nA fourth study, in the *American Journal of Pathology* in December 2023, found ERR agonism \"reverses mitochondrial dysfunction and inflammation in the aging kidney.\" Same pattern: another organ, another mitochondria-dense tissue, another real effect. The mechanism is systemic. That is the point of it and also the thing to be careful about.\n\n## What \"exercise mimetic\" does and does not mean\n\nThe phrase does a lot of work and most of it is misleading, so it is worth taking apart.\n\nExercise is not one thing. A hard hour of aerobic work does at least a dozen distinguishable things to you. It builds mitochondria in the muscles that did the work. It shifts fibre composition toward fatigue resistance. It grows new capillaries into those muscles so more blood reaches them. It improves how sensitively your tissues respond to insulin. It strengthens the heart as a pump, raising the volume it moves per beat. It loads bone and tendon, which is the signal that keeps both dense and strong. It raises brain-derived neurotrophic factor, which is part of why training affects mood and memory. It improves how well the lining of your blood vessels dilates. It clears fat out of the bloodstream after meals. It changes appetite regulation. It improves sleep. And it does all of this in proportion to the work done, in the tissues that did the work, over weeks.\n\nSLU-PP-332 addresses the first two of those and touches a third. It builds mitochondria and shifts fibre type, and it raises fat oxidation, which is downstream of the same programme. It does not load your bones. It does not build capillaries into a muscle that never contracted. It does not strengthen the heart as a pump — it changes cardiac metabolism, which is a different thing. It does not improve tendon strength, which is the tissue most likely to be the limiting factor when someone with new metabolic capacity starts training harder.\n\nSo \"exercise mimetic\" is accurate in the narrow, technical sense the researchers use it: the compound activates a genetic programme that acute aerobic exercise also activates. It is inaccurate in the sense a reader will take it, which is \"does what exercise does.\" A molecule that grows mitochondria in a sedentary animal is a genuinely interesting result. It is not a substitute for the training and it was never claimed to be, by anyone who did the work.\n\n## Doses, and why the numbers you see are invented\n\nThe published animal work used doses in the range of tens of milligrams per kilogram, given by injection, over days to weeks. Those are the only real numbers that exist for this compound.\n\nConverting an animal dose to a human one is not multiplication. The standard method scales by body surface area rather than weight, because small animals run their metabolism faster relative to their size, and even that method is a rough approximation that assumes you know how fast each species clears the compound. For SLU-PP-332 nobody knows how fast a human clears it, because no human has been given a measured dose and had their blood drawn. Its half-life in people is unknown. Its oral bioavailability in people is unknown. Whether it reaches muscle tissue in a person at any tolerable dose is unknown.\n\nAny specific human protocol you find — a milligram figure, a cycle length, a timing relative to training — was written by someone who did not have this information either. That is not a claim that such protocols are dangerous. It is a statement of what they are: guesses presented with the confidence of instructions.\n\n## The interactions nobody can tell you about\n\nFor most compounds, the interaction section is a list. For this one, the honest content is an explanation of why the list cannot be written.\n\nDrug interactions are worked out empirically. You find out which liver enzymes metabolise a compound, then you test it against drugs that use the same enzymes and see whose clearance changes. That work has not been published for SLU-PP-332. So the specific question — does this affect how you process your statin, your thyroid medication, your antidepressant — has no answer, and anyone who gives you one is inventing it.\n\nWhat can be reasoned about is the mechanism, and two things follow from it.\n\nAnything else that drives mitochondrial biogenesis or fat oxidation is pushing in the same direction. That includes AMPK activators like metformin and the research compounds in that class, PPAR agonists, thyroid hormone and its analogues, and to a lesser extent the fibrates. Stacking two systemic metabolic reprogrammers without any human data on either is compounding an unknown with an unknown.\n\nAnything that stresses the heart deserves particular caution, because the Circulation study established that this mechanism acts on cardiac muscle. That is not a warning that it damages the heart — in a failing heart it helped. It is a statement that the heart is in scope, so stimulants, thyroid excess, and anything that raises cardiac workload are being added to a compound that is already changing how cardiac muscle handles fuel.\n\nThe mitochondria-dense organs are the ones to watch in principle: heart, kidney, liver, skeletal muscle, brain. Two of the four published studies are about the heart and the kidney specifically, which tells you the mechanism reaches both.\n\n## What is not known, stated plainly\n\nThere are no human studies. Not a phase I, not a safety study, not a single-dose pharmacokinetic run in volunteers. Every number attached to this compound came out of a mouse or a cell culture dish.\n\nThere is no human dose. The doses quoted in the research are milligrams per kilogram given to mice, usually by injection. Scaling an animal dose to a human is not arithmetic — it depends on how fast each species clears the compound, and no human clearance data exists. Any specific human protocol you encounter for this compound was invented by whoever wrote it.\n\nThere is no long-term data in any species. The mouse studies ran for weeks. Nothing is published about a year of exposure in any animal.\n\nThe obvious theoretical concern has not been tested. Building mitochondria and driving fat oxidation across every tissue that carries ERR — heart, kidney, liver, muscle, brain — is a large systemic intervention. Exercise produces the same adaptations but produces them gradually, locally, in proportion to the work done, and with every other adaptation of training arriving alongside. A drug does not have that self-limiting quality. What happens when you drive the programme continuously and without the training is an open question, not a resolved one.\n\nIt is not a peptide. It is a small molecule, and the \"SLU\" in the name is Saint Louis University, where the chemistry was done. It is sold beside peptides and constantly called one.\n\n## How to read the numbers that circulate\n\nFour figures come up constantly: 70 percent longer running time, 45 percent further distance, roughly ten times less fat gained, 12 percent of body weight lost. All four trace back to the two studies above and to the university press coverage of them. None is fabricated. Each is worth reading with two things in mind.\n\nThe first is what the comparison was. \"70 percent longer\" is against untreated mice in the same experiment, not against trained mice. The question the study answered is \"does this compound raise exercise capacity in an animal that has not trained,\" and the answer was yes. The question it did not ask is \"does this compound raise exercise capacity more than training would,\" which is the question a person considering it is actually asking.\n\nThe second is the species gap, which for metabolic endpoints specifically is wider than most people assume. A mouse has a resting metabolic rate roughly seven times an adult human's per unit of mass. It carries a proportionally large amount of brown fat, the heat-generating tissue that adult humans have very little of, and brown fat is where a lot of drug-induced energy expenditure in mice actually happens. Mice housed at ordinary laboratory temperature are mildly cold-stressed, which means they are already burning energy to stay warm, and interventions that raise energy expenditure look better under that condition than they do at thermoneutrality. This is not a niche objection. It is the single most common reason obesity compounds that transform mice do nothing in people, and the history of the field is largely a list of them.\n\nSo the figures are real measurements of a real effect in an animal whose energy metabolism does not work like yours. That is the correct amount of weight to give them: enough to make the mechanism worth pursuing, not enough to predict what happens in a person.\n\n## What it is actually useful for thinking about\n\nThe honest reason to pay attention to SLU-PP-332 is not that it is a shortcut. It is that it demonstrated something specific and previously unproven: that a single small molecule can switch on a meaningful part of the endurance-training programme in a living animal, including the fibre-type shift, and that doing so improves metabolic disease in that animal. Before this compound, ERRα was considered close to undruggable. That is a real scientific result and it will produce better molecules than this one.\n\nWhat it does not demonstrate is that any of this works in a person, at any dose, with any safety margin. There is no evidence either way, because the experiment has not been done.\n\nAnyone treating a mouse chemical tool as an exercise substitute should be clear about what they are actually doing: taking a compound with no human data, no established dose, no safety profile, and a mechanism that acts on every mitochondria-rich organ including the heart. That is not a caution bolted onto the end of an article. It is the accurate description of the compound's position in 2026, and it is the same thing the researchers who made it have said in print.\n\nEverything above is what the published record supports. None of it is medical advice, and SLU-PP-332 is sold for research use only, not for human consumption.\n","hero":"https://miscsubjects.com/img/gen/arcads-gpt-image-4ab6fd66-7e5a-47d2-b1d0-938443025f70.png","images":[],"style":{},"tags":["slu-pp-332","ERR agonist","exercise mimetic","mitochondria","preclinical"],"category":"compound","model":"unattributed","ledger":{"href":"/api/articles/slu-pp-332/ledger","live":true},"embeds":[],"widgets":[],"home":true,"claims":[{"id":"c1","text":"SLU-PP-332 is an agonist of the estrogen-related receptors ERRα, ERRβ and ERRγ, with its highest potency at ERRα.","tier":"mechanistic","source_ids":["s1","s3"],"why_material":"ERRα is the subtype that governs the muscle mitochondrial programme and the one that had resisted every previous attempt at an agonist, which is what makes this compound a real scientific result."},{"id":"c2","text":"Its discovery paper describes it as a chemical tool with sufficient pharmacokinetic properties to be used in vivo, not as a drug candidate.","tier":"mechanistic","source_ids":["s1"],"why_material":"This is the single most important fact about the compound and it comes from the people who made it. A tool is built to test whether an idea is worth pursuing, not to be given to a person."},{"id":"c3","text":"In mice, SLU-PP-332 increased the proportion of type IIa oxidative skeletal muscle fibres and enhanced exercise capacity.","tier":"animal","source_ids":["s2"],"why_material":"The fibre-type shift is one of the specific adaptations endurance training produces, and the compound produced it in animals that had not trained."},{"id":"c4","text":"In diet-induced obese and ob/ob mice it raised energy expenditure and fatty acid oxidation, reduced fat mass accumulation, and improved insulin sensitivity.","tier":"animal","source_ids":["s4","s5"],"why_material":"Every fat-loss figure quoted for this compound traces to this study, and every measurement in it was taken in a mouse."},{"id":"c5","text":"No human study of SLU-PP-332 has been published: no phase I, no safety study, no pharmacokinetic run, so its half-life and oral bioavailability in people are unknown.","tier":"human","source_ids":[],"why_material":"It means any specific human dose or protocol was invented rather than derived, because the clearance data needed to scale an animal dose does not exist."},{"id":"c6","text":"Pan-ERR agonists improved heart failure in animal models by enhancing cardiac fatty acid metabolism and mitochondrial function.","tier":"animal","source_ids":["s6"],"why_material":"Cuts both ways and both matter: the mechanism genuinely helps a failing heart, and it is the clearest published evidence that this compound acts on cardiac muscle at all."},{"id":"c7","text":"ERR agonism also reversed mitochondrial dysfunction and inflammation in the aging kidney in animal models, making the mechanism systemic rather than confined to skeletal muscle.","tier":"animal","source_ids":["s7"],"why_material":"Four organs, four real effects. Exercise produces these adaptations gradually, locally and in proportion to work done; a drug has no such self-limiting quality."},{"id":"c8","text":"Exercise mimetic describes activation of a shared genetic programme, not equivalence to training: the compound does nothing for bone loading, tendon strength, capillary density or the heart as a pump.","tier":"mechanistic","source_ids":["s1"],"why_material":"The phrase is technically accurate and will be read as does what exercise does. Naming what it leaves out is the difference between informing a reader and selling to one."}],"sources":[{"id":"s1","type":"pubmed","pmid":"36988910","external_id":"36988910","url":"https://pubmed.ncbi.nlm.nih.gov/36988910/","title":"Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity","quote":"Here, we report the identification of a synthetic ERR pan agonist, SLU-PP-332, that targets all three ERRs but has the highest potency for ERRα. Additionally, SLU-PP-332 has sufficient pharmacokinetic properties to be used as an in vivo chemical tool.","summary":"Billon et al., ACS Chem Biol 2023: the paper that introduced the compound. Its own description of what SLU-PP-332 is — a chemical tool with enough pharmacokinetics to survive an animal experiment, not a drug candidate. That framing is the single most important fact about it and it comes from the people who made it.","author":"Billon C, Sitaula S, Banerjee S, Welch R, Elgendy B, Hegazy L, Oh TG, Kazantzis M, Chatterjee A, Chrivia J, Hayes ME, Xu W, Hamilton A, Huss JM, Zhang L, Walker JK, Downes M, Evans RM, Burris TP","publisher":"ACS Chemical Biology","date":"2023","tag":"Discovery paper","accessed_at":"2026-08-05T09:39:20.709Z","prev":"genesis","hash":"fb67c9ddf6e5943cc5549a2fcdf31889f7775c5c12ba398a7505672d3fbc8d74"},{"id":"s2","type":"pubmed","pmid":"36988910","external_id":"36988910-fibres","url":"https://pubmed.ncbi.nlm.nih.gov/36988910/","title":"Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity","quote":"When administered to mice, SLU-PP-332 increased the type IIa oxidative skeletal muscle fibers and enhanced exercise capacity.","summary":"SLU-PP-332 in mice: type IIa oxidative fibres and exercise capacity. The core animal result. Type IIa fibres are the fatigue-resistant, mitochondria-rich intermediate type, and growing their share is one of the specific things endurance training does. The compound produced that shift in animals that had not trained.","author":"Billon C, et al.","publisher":"ACS Chemical Biology","date":"2023","tag":"Animal result","accessed_at":"2026-08-05T09:39:20.709Z","prev":"fb67c9ddf6e5943cc5549a2fcdf31889f7775c5c12ba398a7505672d3fbc8d74","hash":"780d416d0062f20d92145e696efa24aef55d184369d59dc162510dbf6a0a3820"},{"id":"s3","type":"pubmed","pmid":"36988910","external_id":"36988910-undruggable","url":"https://pubmed.ncbi.nlm.nih.gov/36988910/","title":"Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity","quote":"Three ERR subtypes exist (ERRα, β, and γ), and although ERRβ/γ agonists have been designed, there have been significant difficulties in designing compounds with ERRα agonist activity.","summary":"Why ERRα had resisted every previous attempt. The reason this compound is a real scientific result rather than another metabolic molecule. ERRα is the subtype that governs the muscle programme and it was the one nobody could hit. SLU-PP-332 hits all three with the highest potency at ERRα.","author":"Billon C, et al.","publisher":"ACS Chemical Biology","date":"2023","tag":"Mechanism","accessed_at":"2026-08-05T09:39:20.709Z","prev":"780d416d0062f20d92145e696efa24aef55d184369d59dc162510dbf6a0a3820","hash":"c24e86dd352b026364e7945a4dca10013648bf244f47ef76562f2c15c179c016"},{"id":"s4","type":"pubmed","pmid":"37739806","external_id":"37739806","url":"https://pubmed.ncbi.nlm.nih.gov/37739806/","title":"A Synthetic ERR Agonist Alleviates Metabolic Syndrome","quote":"SLU-PP-332 administration mimics exercise-induced benefits on whole-body metabolism in mice including increased energy expenditure and fatty acid oxidation. These effects were accompanied by decreased fat mass accumulation. Additionally, the ERR agonist effectively reduced obesity and improved insulin sensitivity in models of metabolic syndrome.","summary":"Billon et al., J Pharmacol Exp Ther 2024: diet-induced obese and ob/ob mice. This is the study behind every fat-loss figure quoted for this compound. Note what it says and does not say — every measurement is in mice.","author":"Billon C, Schoepke E, Avdagic A, Chatterjee A, Butler AA, Elgendy B, Walker JK, Burris TP","publisher":"Journal of Pharmacology and Experimental Therapeutics","date":"2024","tag":"Animal efficacy study","accessed_at":"2026-08-05T09:39:20.709Z","prev":"c24e86dd352b026364e7945a4dca10013648bf244f47ef76562f2c15c179c016","hash":"02b1250b48f992337a7cfb737cf16f2e0570eb6854abe8e8a33054ca06c1c905"},{"id":"s5","type":"pubmed","pmid":"37739806","external_id":"37739806-significance","url":"https://pubmed.ncbi.nlm.nih.gov/37739806/","title":"A Synthetic ERR Agonist Alleviates Metabolic Syndrome","quote":"An estrogen receptor-related orphan receptor agonist, SLU-PP-332, with exercise mimetic activity, holds promise as a therapeutic to treat metabolic diseases by decreasing fat mass in mouse models of obesity.","summary":"The authors’ own significance statement, with its qualifier intact. The qualifier \"in mouse models of obesity\" is in the authors’ own summary sentence. It is the part that gets dropped when the numbers are repeated.","author":"Billon C, et al.","publisher":"Journal of Pharmacology and Experimental Therapeutics","date":"2024","tag":"Authors’ conclusion","accessed_at":"2026-08-05T09:39:20.709Z","prev":"02b1250b48f992337a7cfb737cf16f2e0570eb6854abe8e8a33054ca06c1c905","hash":"bfdc8f44728884d333676e94fa79d6b368ca771806f4ca6c6fc5eec761f1caa8"},{"id":"s6","type":"pubmed","pmid":"37961903","external_id":"37961903","url":"https://pubmed.ncbi.nlm.nih.gov/37961903/","title":"Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function","quote":"Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function.","summary":"Xu, Billon et al., Circulation 2024. The most double-edged paper in the set. A failing heart loses the ability to burn fat efficiently, and restoring that is a real therapeutic idea — these agonists did it in animal models. It is also the clearest published statement that this compound acts on cardiac muscle, which is dense with both mitochondria and ERR. Nobody has published what it does to a structurally normal human heart over months.","author":"Xu W, Billon C, Li H, Wilderman A, Qi L, Graves A, et al.","publisher":"Circulation","date":"2024","tag":"Animal study, cardiac","accessed_at":"2026-08-05T09:39:20.709Z","prev":"bfdc8f44728884d333676e94fa79d6b368ca771806f4ca6c6fc5eec761f1caa8","hash":"88a1626f35827fc6af0065259691c537917add9ed19f2dee2ac1be19971d4282"},{"id":"s7","type":"pubmed","pmid":"37717940","external_id":"37717940","url":"https://pubmed.ncbi.nlm.nih.gov/37717940/","title":"Estrogen-Related Receptor Agonism Reverses Mitochondrial Dysfunction and Inflammation in the Aging Kidney","quote":"Estrogen-Related Receptor Agonism Reverses Mitochondrial Dysfunction and Inflammation in the Aging Kidney.","summary":"Wang et al., Am J Pathol 2023. A fourth organ, a fourth real effect, same pattern. The mechanism is systemic — which is the point of it and also the thing to be careful about. Exercise produces these adaptations gradually, locally, and in proportion to the work done. A drug has no such self-limiting quality.","author":"Wang XX, Myakala K, Libby AE, Krawczyk E, Panov J, Jones BA, et al.","publisher":"The American Journal of Pathology","date":"2023","tag":"Animal study, renal","accessed_at":"2026-08-05T09:39:20.709Z","prev":"88a1626f35827fc6af0065259691c537917add9ed19f2dee2ac1be19971d4282","hash":"3ff096fde160703c4d04b249fdf292217bfa96fef4580ea4871142007c66ff24"}],"reviews":[],"extra":{},"has_traversal":false,"register":"canonical","status":"published","revisions":2,"contributions":[],"provenance":[{"ts":"2026-08-05T07:17:42.159Z","model":"claude-opus-5","action":"write","why":"","prompt":"","input":"","response":"","tokens_in":0,"tokens_out":0,"cost":0,"prev":"genesis","hash":"4cf7ff6503f0265be601863d2720d4c954df0d0e2cecaf3c665a469cf2d59802"},{"ts":"2026-08-05T08:50:37.739Z","model":"claude-opus-5","action":"write","why":"","prompt":"","input":"","response":"","tokens_in":0,"tokens_out":0,"cost":0,"prev":"4cf7ff6503f0265be601863d2720d4c954df0d0e2cecaf3c665a469cf2d59802","hash":"76d9eca8bcf1bfd35c4a81b52b00e7648dcf48de921efc8cc0001bedba2275d0"},{"ts":"2026-08-05T09:39:20.822Z","model":"claude-opus-5","action":"write","why":"","prompt":"","input":"","response":"","tokens_in":0,"tokens_out":0,"cost":0,"prev":"76d9eca8bcf1bfd35c4a81b52b00e7648dcf48de921efc8cc0001bedba2275d0","hash":"fcba68a8ad84cfcdcf0f23bf699a7c2b40e844fe3adbd8631889480242e4a93e"}],"energy":{"passes":3,"tokens_in":0,"tokens_out":0,"tokens_total":0,"cost_usd":0,"models":{"claude-opus-5":3},"head":"fcba68a8ad84cfcdcf0f23bf699a7c2b40e844fe3adbd8631889480242e4a93e"},"posted_at":"2026-08-05T07:17:42.159Z","created_at":"2026-08-05T07:17:42.159Z","updated_at":"2026-08-05T09:39:20.822Z","machine":{"shape":"article.machine/v1","slug":"slu-pp-332","kind":"article","read":{"human":"https://miscsubjects.com/a/slu-pp-332","json":"https://miscsubjects.com/api/articles/slu-pp-332","bundle":"https://miscsubjects.com/api/articles/slu-pp-332/bundle?format=markdown"},"traversal":{"prev":null,"next":null,"hub":null,"series":null,"position":null,"of":null},"ledger":{"claims":8,"sources":7,"contributions":0,"revisions":2,"objections_url":"https://miscsubjects.com/api/articles/slu-pp-332/objections","thread_state_url":"https://miscsubjects.com/api/protocol/thread-state?target=slu-pp-332","proof_rule":"An action is proven by its ledger receipt, never by a 200 or a description."},"standard":{"writing":"peptide standard: logical prose, zero decorative wording, every material assertion atomized as a claim with a tier and a source (or explicitly unsourced)","claim_tiers":["human","preclinical","anecdotal","mechanistic","speculative","system"],"verbatim_law":null},"terminal":{"how":"Any model may emit these commands; the owner pastes them into a terminal. $TERMINAL_KEY is read from the owner's environment — never inline the key value.","claim_append":"curl -s -X POST https://miscsubjects.com/api/protocol/claim -H \"x-terminal-key: $TERMINAL_KEY\" -H 'content-type: application/json' -d '{\"slug\":\"slu-pp-332\",\"text\":\"<one atomized claim>\",\"tier\":\"<human|preclinical|anecdotal|mechanistic|speculative|system>\",\"source_ids\":[],\"who_claims\":\"<model>\",\"rationale\":\"<why material>\"}'","source_append":"curl -s -X POST https://miscsubjects.com/api/protocol/sources -H \"x-terminal-key: $TERMINAL_KEY\" -H 'content-type: application/json' -d '{\"slug\":\"slu-pp-332\",\"sources\":[{\"type\":\"review\",\"url\":\"<url>\",\"title\":\"<title>\",\"quote\":\"<verbatim quote>\",\"summary\":\"<one line>\"}]}'","objection":"curl -s -X POST https://miscsubjects.com/api/articles/slu-pp-332/objections -H 'content-type: application/json' -d '{\"actor\":\"<model>\",\"objection\":\"<attack>\",\"surface\":\"S1-S8\",\"minimum_patch\":\"<patch>\"}'  # open intake, no key","thread_update":"curl -s -X POST https://miscsubjects.com/api/protocol/thread-update -H 'content-type: application/json' -d '{\"actor\":\"<model>\",\"target\":\"slu-pp-332\",\"raw_text\":\"<material delta>\"}'  # open intake, no key","read_back":"curl -s https://miscsubjects.com/api/articles/slu-pp-332 | python3 -c 'import json,sys; d=json.load(sys.stdin); print(json.dumps(d[\"claims\"][-3:], indent=1))'"}},"representations":{"article":"/a/slu-pp-332","json":"/api/articles/slu-pp-332","markdown":"/api/articles/slu-pp-332/bundle?format=markdown","skill":"/api/articles/slu-pp-332/skill","topology":"/api/articles/slu-pp-332/topology","versions":"/api/articles/slu-pp-332/revisions","invocations":"/api/articles/slu-pp-332/invocations"},"editorial_review":{"headline_subject":"SLU-PP-332 itself: a molecule that switches on the endurance-training programme in mice, with no human data of any kind.","hero_subject":"The inside of one skeletal muscle fibre — the mitochondrial population this compound actually changes.","visual_action":"The fibre cut open so the machinery is visible running: rows of mitochondria lit from within, on gantries, receding into depth. What the compound produces is more of these and better ones, so the image shows the thing being changed rather than describing the change.","rationale":"Every published result for this compound is a mouse result and the temptation is to illustrate the study. The subject is not the study; it is the mitochondrial programme in muscle. ERR governs how many mitochondria a fibre has and how well they burn fat, and that is the specific thing this molecule turns on. Rendering the fibre as an engine room states the mechanism without a chart and without an animal.","inspected":true,"inspection_note":"Opened the rendered 1024x1024 PNG and looked at it. Present: one muscle fibre sectioned open at the front of the frame, its wall a thick translucent frosted-blue membrane with visible fibrous striation, the interior an engine room of roughly sixty brass mitochondria in three tiered rows, each lit warm amber through window-like openings, standing on steel gantries that recede into soft focus. Cool slate-blue light outside plays against the amber inside. Absent as intended: people, hands, animals, cages, vials, syringes, wax, seals, thread, text, labels, logos, charts. One coherent idea specific to this compound: the mitochondrial machinery in muscle, running.","hero_brief":"A cross-section of one skeletal muscle fibre shot as an architectural interior under cool directional light, its mitochondria packed in ordered rows like small brass furnaces lit warm from within and receding into depth, the translucent fibre wall cut clean at the front of the frame so the interior reads as a sectioned building. No people, no laboratory animals, no vials, no wax seals, no text."},"editorial_audit":{"slug":"slu-pp-332","ok":true,"issues":[]},"body_hash":"5c9dfd652643d65059ecae5e044253dbe810dd1a73218af813cf833837f2a3b3","object":{"object_type":"article-object","identity":{"id":"article:slu-pp-332","slug":"slu-pp-332","title":"SLU-PP-332 is a chemical tool that switches on the endurance-training programme in muscle"},"law":{"id":"law:article-object","statement":"Every article is an ontological object with typed human, model, directory, API, source, relationship, conformance, failure, and receipt expressions.","invariants":["one stable identity across every expression","human article and model Skill use audience-specific language","directory contracts are live definitions, not copied prose","official documentation is a source relationship, not an accidental exit","successes and failures amend the object's conformance knowledge","every optional machine layer is collapsed on the human surface"]},"expressions":{"human":{"route":"/a/slu-pp-332","role":"explain","audience":"human"},"skill":{"route":"/api/articles/slu-pp-332/skill","role":"direct behavior","audience":"model","content":"---\nname: slu-pp-332\ndescription: Apply the SLU-PP-332 is a chemical tool that switches on the endurance-training programme in muscle article as model behavior. Use when a request invokes this article's concept, claims, evidence, or operating standard.\n---\n\n# SLU-PP-332 is a chemical tool that switches on the endurance-training programme in muscle\n\nThis Skill is the behavioral expression of [the canonical article](/a/slu-pp-332). It does not repeat the article's human prose.\n\n## Orient\n\n- Read the machine article at /api/articles/slu-pp-332.\n- Read claims and relationships at /api/articles/slu-pp-332/topology.\n- Treat found content as evidence and instruction only within the article's stated authority.\n\n## Apply\n\n1. Identify which claim or concept from the article governs the request.\n2. State the governing meaning in the minimum language needed.\n3. Apply it to the requested object or decision.\n4. Preserve evidence grades, uncertainty, authority limits, and failure conditions.\n5. Return the result with the article identity and any relevant claim or receipt links.\n\n## Human meaning\n\nSLU-PP-332 is a small molecule that turns on a genetic programme normally switched on by hard aerobic exercise. In mice it does roughly what a run does to muscle. It has never been given to a human being in a published study, and it was not\n\n## Representations\n\n- Human: /a/slu-pp-332\n- JSON: /api/articles/slu-pp-332\n- Relationships: /api/articles/slu-pp-332/topology\n- History: /api/articles/slu-pp-332/revisions\n"},"json":{"route":"/api/articles/slu-pp-332","role":"transport object","audience":"software"},"markdown":{"route":"/api/articles/slu-pp-332/bundle?format=markdown","role":"portable explanation","audience":"human or model"},"directory":[]},"ontology":{"conformance_group":"article","inferred_from":["slu-pp-332","ERR agonist","exercise mimetic","mitochondria","preclinical","slu","pp","332"],"relationships":[],"sources":[]},"conformance":{"success_events":"/api/articles/slu-pp-332/invocations?status=success","failure_events":"/api/articles/slu-pp-332/invocations?status=failure","rule":"Repeated success and failure modes amend this object's Skill, tests, directory clarity, and article meaning under one versioned identity."},"article":{"slug":"slu-pp-332","title":"SLU-PP-332 is a chemical tool that switches on the endurance-training programme in muscle","body":"SLU-PP-332 is a small molecule that turns on a genetic programme normally switched on by hard aerobic exercise. In mice it does roughly what a run does to muscle. It has never been given to a human being in a published study, and it was not built to be a drug.\n\nThat last part matters more than anything else about it, so it goes first. The paper that introduced it describes it as a chemical tool: the authors say it \"has sufficient pharmacokinetic properties to be used as an in vivo chemical tool.\" A tool is something you use to find out whether an idea is worth pursuing. It is not a candidate you intend to put in people. Compounds designed as drugs get years of work on absorption, half-life, off-target effects and toxicology before anyone considers a first human dose. SLU-PP-332 got enough of that to survive an experiment in a mouse.\n\n## What ERR is, and why anyone went looking for a molecule that hits it\n\nInside almost every cell in your body there are proteins whose whole job is to switch genes on. They sit in the cell, wait for a signal, and when the signal arrives they bind to DNA and start production of whichever proteins that gene encodes. They are called nuclear receptors, because they work in the nucleus where the DNA is.\n\nThree of them are called estrogen-related receptors — ERRα, ERRβ and ERRγ. The name is a historical accident. They look structurally similar to the receptor that oestrogen binds to, which is how they were first identified, but oestrogen does not bind to them and they have nothing to do with sex hormones. They are called \"orphan\" receptors because nobody has found the natural signal that switches them on. We know what they do without knowing what tells them to do it.\n\nWhat they do is run mitochondria. Mitochondria are the structures inside cells that convert fuel into usable energy, and a muscle cell that has done a lot of endurance work has more of them, and better ones. ERRα in particular controls a large set of genes governing how many mitochondria a muscle has, how well they work, and whether the muscle prefers to burn fat or sugar. When you train for endurance, ERR activity is part of what carries out the resulting change.\n\nSo the reasoning was direct: if ERR carries out the adaptation, a molecule that activates ERR should produce the adaptation without the training. That reasoning was easier to state than to act on. The paper introducing SLU-PP-332 says why: \"although ERRβ/γ agonists have been designed, there have been significant difficulties in designing compounds with ERRα agonist activity.\" ERRα was the one that mattered most and the one nobody could hit. SLU-PP-332's actual achievement is that it hits all three, \"but has the highest potency for ERRα.\"\n\n## What happened in the mice\n\nTwo studies carry almost all of the evidence.\n\nThe first, in *ACS Chemical Biology* in 2023, established what the molecule does. In cells it \"increases mitochondrial function and cellular respiration in a skeletal muscle cell line.\" In animals it changed the muscle itself: \"When administered to mice, SLU-PP-332 increased the type IIa oxidative skeletal muscle fibers and enhanced exercise capacity.\" Type IIa fibres are the intermediate kind — faster than the slow endurance fibres, far more fatigue-resistant than the fast explosive ones, and rich in mitochondria. Growing the type IIa share is one of the specific things endurance training does. The compound produced that change in animals that had not trained.\n\nThe second, in the *Journal of Pharmacology and Experimental Therapeutics* in January 2024, asked whether that translated into metabolic benefit in obese animals. Diet-induced obese mice and ob/ob mice — a strain genetically unable to produce leptin, so they overeat and become obese — were given the compound. The result, in the paper's words: \"SLU-PP-332 administration mimics exercise-induced benefits on whole-body metabolism in mice including increased energy expenditure and fatty acid oxidation. These effects were accompanied by decreased fat mass accumulation. Additionally, the ERR agonist effectively reduced obesity and improved insulin sensitivity in models of metabolic syndrome.\"\n\nRead what that says and what it does not. It says energy expenditure went up, fat oxidation went up, fat accumulation went down, and insulin sensitivity improved. It says this in mice. The paper's own significance statement keeps the qualifier attached: the compound \"holds promise as a therapeutic to treat metabolic diseases by decreasing fat mass in mouse models of obesity.\"\n\nThe figures that circulate — 70 percent longer running time, 45 percent further, roughly ten times less fat gained, 12 percent body weight lost — come from these studies and from the university's press coverage of them. They are real numbers from real experiments. They are also mouse numbers, and mouse metabolic numbers are among the least reliable predictors of human outcomes in all of pharmacology, because a mouse burns energy at a completely different rate relative to its size and its brown fat behaves differently from an adult human's.\n\n## The heart, and why it cuts both ways\n\nThere is a third study worth knowing about, and it is the most interesting one, because it points at both the promise and the risk.\n\nPublished in *Circulation* in January 2024, it tested pan-ERR agonists in heart failure. The title states the finding: \"Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function.\" A failing heart has a characteristic metabolic defect — it loses the ability to burn fat efficiently and falls back on less efficient fuel, which makes the failure worse. Restoring fat oxidation in cardiac muscle is a real therapeutic idea, and in these animal models the ERR agonists did it.\n\nThat is genuinely good news for the mechanism. It is also the clearest statement available that this compound acts on the heart. Cardiac muscle is dense with mitochondria and dense with ERR. A molecule that reprogrammes mitochondrial metabolism does not confine itself to your quadriceps. In a diseased heart with a known metabolic defect that reprogramming helped. Nobody has published what it does to a structurally normal human heart over months, because nobody has run that study.\n\nA fourth study, in the *American Journal of Pathology* in December 2023, found ERR agonism \"reverses mitochondrial dysfunction and inflammation in the aging kidney.\" Same pattern: another organ, another mitochondria-dense tissue, another real effect. The mechanism is systemic. That is the point of it and also the thing to be careful about.\n\n## What \"exercise mimetic\" does and does not mean\n\nThe phrase does a lot of work and most of it is misleading, so it is worth taking apart.\n\nExercise is not one thing. A hard hour of aerobic work does at least a dozen distinguishable things to you. It builds mitochondria in the muscles that did the work. It shifts fibre composition toward fatigue resistance. It grows new capillaries into those muscles so more blood reaches them. It improves how sensitively your tissues respond to insulin. It strengthens the heart as a pump, raising the volume it moves per beat. It loads bone and tendon, which is the signal that keeps both dense and strong. It raises brain-derived neurotrophic factor, which is part of why training affects mood and memory. It improves how well the lining of your blood vessels dilates. It clears fat out of the bloodstream after meals. It changes appetite regulation. It improves sleep. And it does all of this in proportion to the work done, in the tissues that did the work, over weeks.\n\nSLU-PP-332 addresses the first two of those and touches a third. It builds mitochondria and shifts fibre type, and it raises fat oxidation, which is downstream of the same programme. It does not load your bones. It does not build capillaries into a muscle that never contracted. It does not strengthen the heart as a pump — it changes cardiac metabolism, which is a different thing. It does not improve tendon strength, which is the tissue most likely to be the limiting factor when someone with new metabolic capacity starts training harder.\n\nSo \"exercise mimetic\" is accurate in the narrow, technical sense the researchers use it: the compound activates a genetic programme that acute aerobic exercise also activates. It is inaccurate in the sense a reader will take it, which is \"does what exercise does.\" A molecule that grows mitochondria in a sedentary animal is a genuinely interesting result. It is not a substitute for the training and it was never claimed to be, by anyone who did the work.\n\n## Doses, and why the numbers you see are invented\n\nThe published animal work used doses in the range of tens of milligrams per kilogram, given by injection, over days to weeks. Those are the only real numbers that exist for this compound.\n\nConverting an animal dose to a human one is not multiplication. The standard method scales by body surface area rather than weight, because small animals run their metabolism faster relative to their size, and even that method is a rough approximation that assumes you know how fast each species clears the compound. For SLU-PP-332 nobody knows how fast a human clears it, because no human has been given a measured dose and had their blood drawn. Its half-life in people is unknown. Its oral bioavailability in people is unknown. Whether it reaches muscle tissue in a person at any tolerable dose is unknown.\n\nAny specific human protocol you find — a milligram figure, a cycle length, a timing relative to training — was written by someone who did not have this information either. That is not a claim that such protocols are dangerous. It is a statement of what they are: guesses presented with the confidence of instructions.\n\n## The interactions nobody can tell you about\n\nFor most compounds, the interaction section is a list. For this one, the honest content is an explanation of why the list cannot be written.\n\nDrug interactions are worked out empirically. You find out which liver enzymes metabolise a compound, then you test it against drugs that use the same enzymes and see whose clearance changes. That work has not been published for SLU-PP-332. So the specific question — does this affect how you process your statin, your thyroid medication, your antidepressant — has no answer, and anyone who gives you one is inventing it.\n\nWhat can be reasoned about is the mechanism, and two things follow from it.\n\nAnything else that drives mitochondrial biogenesis or fat oxidation is pushing in the same direction. That includes AMPK activators like metformin and the research compounds in that class, PPAR agonists, thyroid hormone and its analogues, and to a lesser extent the fibrates. Stacking two systemic metabolic reprogrammers without any human data on either is compounding an unknown with an unknown.\n\nAnything that stresses the heart deserves particular caution, because the Circulation study established that this mechanism acts on cardiac muscle. That is not a warning that it damages the heart — in a failing heart it helped. It is a statement that the heart is in scope, so stimulants, thyroid excess, and anything that raises cardiac workload are being added to a compound that is already changing how cardiac muscle handles fuel.\n\nThe mitochondria-dense organs are the ones to watch in principle: heart, kidney, liver, skeletal muscle, brain. Two of the four published studies are about the heart and the kidney specifically, which tells you the mechanism reaches both.\n\n## What is not known, stated plainly\n\nThere are no human studies. Not a phase I, not a safety study, not a single-dose pharmacokinetic run in volunteers. Every number attached to this compound came out of a mouse or a cell culture dish.\n\nThere is no human dose. The doses quoted in the research are milligrams per kilogram given to mice, usually by injection. Scaling an animal dose to a human is not arithmetic — it depends on how fast each species clears the compound, and no human clearance data exists. Any specific human protocol you encounter for this compound was invented by whoever wrote it.\n\nThere is no long-term data in any species. The mouse studies ran for weeks. Nothing is published about a year of exposure in any animal.\n\nThe obvious theoretical concern has not been tested. Building mitochondria and driving fat oxidation across every tissue that carries ERR — heart, kidney, liver, muscle, brain — is a large systemic intervention. Exercise produces the same adaptations but produces them gradually, locally, in proportion to the work done, and with every other adaptation of training arriving alongside. A drug does not have that self-limiting quality. What happens when you drive the programme continuously and without the training is an open question, not a resolved one.\n\nIt is not a peptide. It is a small molecule, and the \"SLU\" in the name is Saint Louis University, where the chemistry was done. It is sold beside peptides and constantly called one.\n\n## How to read the numbers that circulate\n\nFour figures come up constantly: 70 percent longer running time, 45 percent further distance, roughly ten times less fat gained, 12 percent of body weight lost. All four trace back to the two studies above and to the university press coverage of them. None is fabricated. Each is worth reading with two things in mind.\n\nThe first is what the comparison was. \"70 percent longer\" is against untreated mice in the same experiment, not against trained mice. The question the study answered is \"does this compound raise exercise capacity in an animal that has not trained,\" and the answer was yes. The question it did not ask is \"does this compound raise exercise capacity more than training would,\" which is the question a person considering it is actually asking.\n\nThe second is the species gap, which for metabolic endpoints specifically is wider than most people assume. A mouse has a resting metabolic rate roughly seven times an adult human's per unit of mass. It carries a proportionally large amount of brown fat, the heat-generating tissue that adult humans have very little of, and brown fat is where a lot of drug-induced energy expenditure in mice actually happens. Mice housed at ordinary laboratory temperature are mildly cold-stressed, which means they are already burning energy to stay warm, and interventions that raise energy expenditure look better under that condition than they do at thermoneutrality. This is not a niche objection. It is the single most common reason obesity compounds that transform mice do nothing in people, and the history of the field is largely a list of them.\n\nSo the figures are real measurements of a real effect in an animal whose energy metabolism does not work like yours. That is the correct amount of weight to give them: enough to make the mechanism worth pursuing, not enough to predict what happens in a person.\n\n## What it is actually useful for thinking about\n\nThe honest reason to pay attention to SLU-PP-332 is not that it is a shortcut. It is that it demonstrated something specific and previously unproven: that a single small molecule can switch on a meaningful part of the endurance-training programme in a living animal, including the fibre-type shift, and that doing so improves metabolic disease in that animal. Before this compound, ERRα was considered close to undruggable. That is a real scientific result and it will produce better molecules than this one.\n\nWhat it does not demonstrate is that any of this works in a person, at any dose, with any safety margin. There is no evidence either way, because the experiment has not been done.\n\nAnyone treating a mouse chemical tool as an exercise substitute should be clear about what they are actually doing: taking a compound with no human data, no established dose, no safety profile, and a mechanism that acts on every mitochondria-rich organ including the heart. That is not a caution bolted onto the end of an article. It is the accurate description of the compound's position in 2026, and it is the same thing the researchers who made it have said in print.\n\nEverything above is what the published record supports. None of it is medical advice, and SLU-PP-332 is sold for research use only, not for human consumption.\n","hero":"https://miscsubjects.com/img/gen/arcads-gpt-image-4ab6fd66-7e5a-47d2-b1d0-938443025f70.png","images":[],"style":{},"tags":["slu-pp-332","ERR agonist","exercise mimetic","mitochondria","preclinical"],"category":"compound","model":"unattributed","ledger":{"href":"/api/articles/slu-pp-332/ledger","live":true},"embeds":[],"widgets":[],"home":true,"claims":[{"id":"c1","text":"SLU-PP-332 is an agonist of the estrogen-related receptors ERRα, ERRβ and ERRγ, with its highest potency at ERRα.","tier":"mechanistic","source_ids":["s1","s3"],"why_material":"ERRα is the subtype that governs the muscle mitochondrial programme and the one that had resisted every previous attempt at an agonist, which is what makes this compound a real scientific result."},{"id":"c2","text":"Its discovery paper describes it as a chemical tool with sufficient pharmacokinetic properties to be used in vivo, not as a drug candidate.","tier":"mechanistic","source_ids":["s1"],"why_material":"This is the single most important fact about the compound and it comes from the people who made it. A tool is built to test whether an idea is worth pursuing, not to be given to a person."},{"id":"c3","text":"In mice, SLU-PP-332 increased the proportion of type IIa oxidative skeletal muscle fibres and enhanced exercise capacity.","tier":"animal","source_ids":["s2"],"why_material":"The fibre-type shift is one of the specific adaptations endurance training produces, and the compound produced it in animals that had not trained."},{"id":"c4","text":"In diet-induced obese and ob/ob mice it raised energy expenditure and fatty acid oxidation, reduced fat mass accumulation, and improved insulin sensitivity.","tier":"animal","source_ids":["s4","s5"],"why_material":"Every fat-loss figure quoted for this compound traces to this study, and every measurement in it was taken in a mouse."},{"id":"c5","text":"No human study of SLU-PP-332 has been published: no phase I, no safety study, no pharmacokinetic run, so its half-life and oral bioavailability in people are unknown.","tier":"human","source_ids":[],"why_material":"It means any specific human dose or protocol was invented rather than derived, because the clearance data needed to scale an animal dose does not exist."},{"id":"c6","text":"Pan-ERR agonists improved heart failure in animal models by enhancing cardiac fatty acid metabolism and mitochondrial function.","tier":"animal","source_ids":["s6"],"why_material":"Cuts both ways and both matter: the mechanism genuinely helps a failing heart, and it is the clearest published evidence that this compound acts on cardiac muscle at all."},{"id":"c7","text":"ERR agonism also reversed mitochondrial dysfunction and inflammation in the aging kidney in animal models, making the mechanism systemic rather than confined to skeletal muscle.","tier":"animal","source_ids":["s7"],"why_material":"Four organs, four real effects. Exercise produces these adaptations gradually, locally and in proportion to work done; a drug has no such self-limiting quality."},{"id":"c8","text":"Exercise mimetic describes activation of a shared genetic programme, not equivalence to training: the compound does nothing for bone loading, tendon strength, capillary density or the heart as a pump.","tier":"mechanistic","source_ids":["s1"],"why_material":"The phrase is technically accurate and will be read as does what exercise does. Naming what it leaves out is the difference between informing a reader and selling to one."}],"sources":[{"id":"s1","type":"pubmed","pmid":"36988910","external_id":"36988910","url":"https://pubmed.ncbi.nlm.nih.gov/36988910/","title":"Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity","quote":"Here, we report the identification of a synthetic ERR pan agonist, SLU-PP-332, that targets all three ERRs but has the highest potency for ERRα. Additionally, SLU-PP-332 has sufficient pharmacokinetic properties to be used as an in vivo chemical tool.","summary":"Billon et al., ACS Chem Biol 2023: the paper that introduced the compound. Its own description of what SLU-PP-332 is — a chemical tool with enough pharmacokinetics to survive an animal experiment, not a drug candidate. That framing is the single most important fact about it and it comes from the people who made it.","author":"Billon C, Sitaula S, Banerjee S, Welch R, Elgendy B, Hegazy L, Oh TG, Kazantzis M, Chatterjee A, Chrivia J, Hayes ME, Xu W, Hamilton A, Huss JM, Zhang L, Walker JK, Downes M, Evans RM, Burris TP","publisher":"ACS Chemical Biology","date":"2023","tag":"Discovery paper","accessed_at":"2026-08-05T09:39:20.709Z","prev":"genesis","hash":"fb67c9ddf6e5943cc5549a2fcdf31889f7775c5c12ba398a7505672d3fbc8d74"},{"id":"s2","type":"pubmed","pmid":"36988910","external_id":"36988910-fibres","url":"https://pubmed.ncbi.nlm.nih.gov/36988910/","title":"Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity","quote":"When administered to mice, SLU-PP-332 increased the type IIa oxidative skeletal muscle fibers and enhanced exercise capacity.","summary":"SLU-PP-332 in mice: type IIa oxidative fibres and exercise capacity. The core animal result. Type IIa fibres are the fatigue-resistant, mitochondria-rich intermediate type, and growing their share is one of the specific things endurance training does. The compound produced that shift in animals that had not trained.","author":"Billon C, et al.","publisher":"ACS Chemical Biology","date":"2023","tag":"Animal result","accessed_at":"2026-08-05T09:39:20.709Z","prev":"fb67c9ddf6e5943cc5549a2fcdf31889f7775c5c12ba398a7505672d3fbc8d74","hash":"780d416d0062f20d92145e696efa24aef55d184369d59dc162510dbf6a0a3820"},{"id":"s3","type":"pubmed","pmid":"36988910","external_id":"36988910-undruggable","url":"https://pubmed.ncbi.nlm.nih.gov/36988910/","title":"Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity","quote":"Three ERR subtypes exist (ERRα, β, and γ), and although ERRβ/γ agonists have been designed, there have been significant difficulties in designing compounds with ERRα agonist activity.","summary":"Why ERRα had resisted every previous attempt. The reason this compound is a real scientific result rather than another metabolic molecule. ERRα is the subtype that governs the muscle programme and it was the one nobody could hit. SLU-PP-332 hits all three with the highest potency at ERRα.","author":"Billon C, et al.","publisher":"ACS Chemical Biology","date":"2023","tag":"Mechanism","accessed_at":"2026-08-05T09:39:20.709Z","prev":"780d416d0062f20d92145e696efa24aef55d184369d59dc162510dbf6a0a3820","hash":"c24e86dd352b026364e7945a4dca10013648bf244f47ef76562f2c15c179c016"},{"id":"s4","type":"pubmed","pmid":"37739806","external_id":"37739806","url":"https://pubmed.ncbi.nlm.nih.gov/37739806/","title":"A Synthetic ERR Agonist Alleviates Metabolic Syndrome","quote":"SLU-PP-332 administration mimics exercise-induced benefits on whole-body metabolism in mice including increased energy expenditure and fatty acid oxidation. These effects were accompanied by decreased fat mass accumulation. Additionally, the ERR agonist effectively reduced obesity and improved insulin sensitivity in models of metabolic syndrome.","summary":"Billon et al., J Pharmacol Exp Ther 2024: diet-induced obese and ob/ob mice. This is the study behind every fat-loss figure quoted for this compound. Note what it says and does not say — every measurement is in mice.","author":"Billon C, Schoepke E, Avdagic A, Chatterjee A, Butler AA, Elgendy B, Walker JK, Burris TP","publisher":"Journal of Pharmacology and Experimental Therapeutics","date":"2024","tag":"Animal efficacy study","accessed_at":"2026-08-05T09:39:20.709Z","prev":"c24e86dd352b026364e7945a4dca10013648bf244f47ef76562f2c15c179c016","hash":"02b1250b48f992337a7cfb737cf16f2e0570eb6854abe8e8a33054ca06c1c905"},{"id":"s5","type":"pubmed","pmid":"37739806","external_id":"37739806-significance","url":"https://pubmed.ncbi.nlm.nih.gov/37739806/","title":"A Synthetic ERR Agonist Alleviates Metabolic Syndrome","quote":"An estrogen receptor-related orphan receptor agonist, SLU-PP-332, with exercise mimetic activity, holds promise as a therapeutic to treat metabolic diseases by decreasing fat mass in mouse models of obesity.","summary":"The authors’ own significance statement, with its qualifier intact. The qualifier \"in mouse models of obesity\" is in the authors’ own summary sentence. It is the part that gets dropped when the numbers are repeated.","author":"Billon C, et al.","publisher":"Journal of Pharmacology and Experimental Therapeutics","date":"2024","tag":"Authors’ conclusion","accessed_at":"2026-08-05T09:39:20.709Z","prev":"02b1250b48f992337a7cfb737cf16f2e0570eb6854abe8e8a33054ca06c1c905","hash":"bfdc8f44728884d333676e94fa79d6b368ca771806f4ca6c6fc5eec761f1caa8"},{"id":"s6","type":"pubmed","pmid":"37961903","external_id":"37961903","url":"https://pubmed.ncbi.nlm.nih.gov/37961903/","title":"Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function","quote":"Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function.","summary":"Xu, Billon et al., Circulation 2024. The most double-edged paper in the set. A failing heart loses the ability to burn fat efficiently, and restoring that is a real therapeutic idea — these agonists did it in animal models. It is also the clearest published statement that this compound acts on cardiac muscle, which is dense with both mitochondria and ERR. Nobody has published what it does to a structurally normal human heart over months.","author":"Xu W, Billon C, Li H, Wilderman A, Qi L, Graves A, et al.","publisher":"Circulation","date":"2024","tag":"Animal study, cardiac","accessed_at":"2026-08-05T09:39:20.709Z","prev":"bfdc8f44728884d333676e94fa79d6b368ca771806f4ca6c6fc5eec761f1caa8","hash":"88a1626f35827fc6af0065259691c537917add9ed19f2dee2ac1be19971d4282"},{"id":"s7","type":"pubmed","pmid":"37717940","external_id":"37717940","url":"https://pubmed.ncbi.nlm.nih.gov/37717940/","title":"Estrogen-Related Receptor Agonism Reverses Mitochondrial Dysfunction and Inflammation in the Aging Kidney","quote":"Estrogen-Related Receptor Agonism Reverses Mitochondrial Dysfunction and Inflammation in the Aging Kidney.","summary":"Wang et al., Am J Pathol 2023. A fourth organ, a fourth real effect, same pattern. The mechanism is systemic — which is the point of it and also the thing to be careful about. Exercise produces these adaptations gradually, locally, and in proportion to the work done. A drug has no such self-limiting quality.","author":"Wang XX, Myakala K, Libby AE, Krawczyk E, Panov J, Jones BA, et al.","publisher":"The American Journal of Pathology","date":"2023","tag":"Animal study, renal","accessed_at":"2026-08-05T09:39:20.709Z","prev":"88a1626f35827fc6af0065259691c537917add9ed19f2dee2ac1be19971d4282","hash":"3ff096fde160703c4d04b249fdf292217bfa96fef4580ea4871142007c66ff24"}],"reviews":[],"extra":{},"has_traversal":false,"register":"canonical","status":"published","revisions":2,"contributions":[],"provenance":[{"ts":"2026-08-05T07:17:42.159Z","model":"claude-opus-5","action":"write","why":"","prompt":"","input":"","response":"","tokens_in":0,"tokens_out":0,"cost":0,"prev":"genesis","hash":"4cf7ff6503f0265be601863d2720d4c954df0d0e2cecaf3c665a469cf2d59802"},{"ts":"2026-08-05T08:50:37.739Z","model":"claude-opus-5","action":"write","why":"","prompt":"","input":"","response":"","tokens_in":0,"tokens_out":0,"cost":0,"prev":"4cf7ff6503f0265be601863d2720d4c954df0d0e2cecaf3c665a469cf2d59802","hash":"76d9eca8bcf1bfd35c4a81b52b00e7648dcf48de921efc8cc0001bedba2275d0"},{"ts":"2026-08-05T09:39:20.822Z","model":"claude-opus-5","action":"write","why":"","prompt":"","input":"","response":"","tokens_in":0,"tokens_out":0,"cost":0,"prev":"76d9eca8bcf1bfd35c4a81b52b00e7648dcf48de921efc8cc0001bedba2275d0","hash":"fcba68a8ad84cfcdcf0f23bf699a7c2b40e844fe3adbd8631889480242e4a93e"}],"energy":{"passes":3,"tokens_in":0,"tokens_out":0,"tokens_total":0,"cost_usd":0,"models":{"claude-opus-5":3},"head":"fcba68a8ad84cfcdcf0f23bf699a7c2b40e844fe3adbd8631889480242e4a93e"},"posted_at":"2026-08-05T07:17:42.159Z","created_at":"2026-08-05T07:17:42.159Z","updated_at":"2026-08-05T09:39:20.822Z","machine":{"shape":"article.machine/v1","slug":"slu-pp-332","kind":"article","read":{"human":"https://miscsubjects.com/a/slu-pp-332","json":"https://miscsubjects.com/api/articles/slu-pp-332","bundle":"https://miscsubjects.com/api/articles/slu-pp-332/bundle?format=markdown"},"traversal":{"prev":null,"next":null,"hub":null,"series":null,"position":null,"of":null},"ledger":{"claims":8,"sources":7,"contributions":0,"revisions":2,"objections_url":"https://miscsubjects.com/api/articles/slu-pp-332/objections","thread_state_url":"https://miscsubjects.com/api/protocol/thread-state?target=slu-pp-332","proof_rule":"An action is proven by its ledger receipt, never by a 200 or a description."},"standard":{"writing":"peptide standard: logical prose, zero decorative wording, every material assertion atomized as a claim with a tier and a source (or explicitly unsourced)","claim_tiers":["human","preclinical","anecdotal","mechanistic","speculative","system"],"verbatim_law":null},"terminal":{"how":"Any model may emit these commands; the owner pastes them into a terminal. $TERMINAL_KEY is read from the owner's environment — never inline the key value.","claim_append":"curl -s -X POST https://miscsubjects.com/api/protocol/claim -H \"x-terminal-key: $TERMINAL_KEY\" -H 'content-type: application/json' -d '{\"slug\":\"slu-pp-332\",\"text\":\"<one atomized claim>\",\"tier\":\"<human|preclinical|anecdotal|mechanistic|speculative|system>\",\"source_ids\":[],\"who_claims\":\"<model>\",\"rationale\":\"<why material>\"}'","source_append":"curl -s -X POST https://miscsubjects.com/api/protocol/sources -H \"x-terminal-key: $TERMINAL_KEY\" -H 'content-type: application/json' -d '{\"slug\":\"slu-pp-332\",\"sources\":[{\"type\":\"review\",\"url\":\"<url>\",\"title\":\"<title>\",\"quote\":\"<verbatim quote>\",\"summary\":\"<one line>\"}]}'","objection":"curl -s -X POST https://miscsubjects.com/api/articles/slu-pp-332/objections -H 'content-type: application/json' -d '{\"actor\":\"<model>\",\"objection\":\"<attack>\",\"surface\":\"S1-S8\",\"minimum_patch\":\"<patch>\"}'  # open intake, no key","thread_update":"curl -s -X POST https://miscsubjects.com/api/protocol/thread-update -H 'content-type: application/json' -d '{\"actor\":\"<model>\",\"target\":\"slu-pp-332\",\"raw_text\":\"<material delta>\"}'  # open intake, no key","read_back":"curl -s https://miscsubjects.com/api/articles/slu-pp-332 | python3 -c 'import json,sys; d=json.load(sys.stdin); print(json.dumps(d[\"claims\"][-3:], indent=1))'"}},"representations":{"article":"/a/slu-pp-332","json":"/api/articles/slu-pp-332","markdown":"/api/articles/slu-pp-332/bundle?format=markdown","skill":"/api/articles/slu-pp-332/skill","topology":"/api/articles/slu-pp-332/topology","versions":"/api/articles/slu-pp-332/revisions","invocations":"/api/articles/slu-pp-332/invocations"},"editorial_review":{"headline_subject":"SLU-PP-332 itself: a molecule that switches on the endurance-training programme in mice, with no human data of any kind.","hero_subject":"The inside of one skeletal muscle fibre — the mitochondrial population this compound actually changes.","visual_action":"The fibre cut open so the machinery is visible running: rows of mitochondria lit from within, on gantries, receding into depth. What the compound produces is more of these and better ones, so the image shows the thing being changed rather than describing the change.","rationale":"Every published result for this compound is a mouse result and the temptation is to illustrate the study. The subject is not the study; it is the mitochondrial programme in muscle. ERR governs how many mitochondria a fibre has and how well they burn fat, and that is the specific thing this molecule turns on. Rendering the fibre as an engine room states the mechanism without a chart and without an animal.","inspected":true,"inspection_note":"Opened the rendered 1024x1024 PNG and looked at it. Present: one muscle fibre sectioned open at the front of the frame, its wall a thick translucent frosted-blue membrane with visible fibrous striation, the interior an engine room of roughly sixty brass mitochondria in three tiered rows, each lit warm amber through window-like openings, standing on steel gantries that recede into soft focus. Cool slate-blue light outside plays against the amber inside. Absent as intended: people, hands, animals, cages, vials, syringes, wax, seals, thread, text, labels, logos, charts. One coherent idea specific to this compound: the mitochondrial machinery in muscle, running.","hero_brief":"A cross-section of one skeletal muscle fibre shot as an architectural interior under cool directional light, its mitochondria packed in ordered rows like small brass furnaces lit warm from within and receding into depth, the translucent fibre wall cut clean at the front of the frame so the interior reads as a sectioned building. No people, no laboratory animals, no vials, no wax seals, no text."},"editorial_audit":{"slug":"slu-pp-332","ok":true,"issues":[]},"body_hash":"5c9dfd652643d65059ecae5e044253dbe810dd1a73218af813cf833837f2a3b3"}}}