Carl read the papersWhat it actually is
SLU-PP-332 is not a peptide. It is a small synthetic molecule (about 290 daltons, no amino acids at all) from a St. Louis research group at Saint Louis University and Washington University. It activates all three estrogen-related receptors (ERRα, ERRβ and ERRγ), most strongly ERRα.
ERRs are orphan nuclear receptors that run the genes for building mitochondria, burning fat and adapting muscle to aerobic exercise. The pitch is an exercise mimetic: some of the training adaptation without the training. It ends up on peptide sites because the same buyers want it.
How it’s thought to work
- ERR agonism — Activates ERRα, β and γ, which control genes for mitochondrial biogenesis, oxidative phosphorylation and fatty acid oxidation.
- Exercise gene program — In mice it switched on an acute aerobic exercise gene program, and the endurance gain disappeared in mice lacking muscle ERRα.
- Fibre-type shift — Increased oxidative type IIa muscle fibres in mice.
- Fat burning — Raised energy expenditure and fat oxidation, and reduced fat gain, in obese mice.
What the research says
Everything is mouse and cell data. In the 2023 paper, mice given 50 mg/kg twice daily by injection into the abdomen for 7 days ran about 70% longer and 45% further than mice given the solvent alone. Follow-ups found less fat gain and better insulin sensitivity in obese mice, and better heart function in a mouse heart-failure model. There are no human trials: ClinicalTrials.gov has none registered. The developers' own 2026 paper on its successor, SLU-PP-915, says SLU-PP-332 lacks oral bioavailability. That matters, because it is sold as capsules.
- Mice, 7 days at 50 mg/kg twice daily (injected): about 70% longer and 45% further to exhaustion.
- Obese mice: higher energy expenditure and fat oxidation, less fat gain, better insulin sensitivity.
- No registered human trial, so no human dose, safety or efficacy data.
- Developers say it lacks oral bioavailability; chemical suppliers list it as insoluble in water.
Reported protocols
These are the doses the peptide community actually reports running (Reddit & forums), alongside published research — logged for education, not as a recommendation to use.
| Parameter | Commonly reported range |
|---|---|
| Human dose | Not established. No human study exists. Mouse studies used 25 to 50 mg/kg twice daily, injected into the abdominal cavity in lab solvents |
| Community dose | Reddit reports range from 250 to 500 mcg a day injected, through 1 to 2 mg, to 5 to 20 mg a day and even 50 to 100 mg a day orally. A 400-fold spread is not a protocol |
| Route | Sold as capsules and as injectable vials; neither form has human absorption data |
| Cycle | Unknown. The longest mouse study we read ran 6 weeks (the heart-failure study) |
| Community tip | Users report the powder will not dissolve in bacteriostatic water, which matches supplier data. A clear 'SLU-PP-332' solution in bac water should make you ask what is actually in the vial |
Common use cases
| Goal | Community protocol notes |
|---|---|
| Endurance research in mice | the only setting with real data |
| Fat loss in people | no human data; mouse obesity models only |
| Sport | banned under WADA S0, and anti-doping labs are already mapping its metabolites |
Mixing it (reconstitution)
Freeze-dried peptides must be reconstituted with bacteriostatic water before they can be measured. Carl’s calculator turns “mg in the vial + ml of water + target dose” into “units on the syringe” — and tells you how long the vial lasts.
→ Open the Reconstitution Calculator
Injection & handling
There is no validated way to take this in people, so there is no injection method here. The mouse studies injected it into the abdominal cavity dissolved in DMSO mixed with Tween or Cremophor, which are lab solvents, not something to improvise at home. Suppliers list it as insoluble in water, and its developers say it is not orally bioavailable. So both retail forms have a problem: capsules may barely absorb, and a vial reconstituted with bacteriostatic water cannot hold the real compound in solution.
Stacks it appears in
- With MOTS-c — A common pairing in endurance threads. MOTS-c is banned by name (WADA S4.4), and we found no study of the combination.
- With 5-Amino-1MQ or AICAR — Lumped together as 'metabolic' compounds online. AICAR is banned by name (WADA S4.4); we found no study of the combination.
Sources
- Billon et al., synthetic ERRα/β/γ agonist enhances exercise capacity, ACS Chem Biol 2023 (PMID 36988910)
- Billon et al., a synthetic ERR agonist alleviates metabolic syndrome, J Pharmacol Exp Ther 2024 (PMID 37739806)
- Xu et al., pan-ERR agonists ameliorate heart failure, Circulation 2024 (PMID 37961903)
- Billon et al., SLU-PP-915, an orally active ERR agonist, J Pharmacol Exp Ther 2026 (PMID 41421047)
- Avliyakulov et al., in vitro metabolites of SLU-PP-332 for doping control, Drug Test Anal 2026 (PMID 41688415)
- Moller et al., in vitro metabolism of SLU-PP-332 and SLU-PP-915, Rapid Commun Mass Spectrom 2026 (PMID 41588687)
- Pradhan et al., ERRα in breast cancer, Biochim Biophys Acta Rev Cancer 2026 (PMID 41475667)
- Selleck: SLU-PP-332 product data
- ClinicalTrials.gov search: SLU-PP-332
- SAHPRA: Peptide Products, Public Information (May 2026)
- WADA 2026 Prohibited List
