Muscle & Performance
SLU-PP-332
aka SLU-PP-332 · slu-pp-332 · slu pp 332 · slupp332 · slu-pp332 · slu 332 · slu332 · exercise pill · exercise in a pill · exercise mimetic · ERR agonist · pan-ERR agonist
Grade
A lab chemical, not a peptide, that made mice run further and gain less fat, sold online as 'exercise in a pill' despite never being tested in humans.
- Class
- Small-molecule ERR (oestrogen-related receptor) agonist, not a peptide despite being sold by peptide shops
- Evidence
- Grade D · Animal data only
- Sport / WADA
- Prohibited at all times under S0 (non-approved substances). It is not named on the 2026 WADA Prohibited List, and section S4.4 (metabolic modulators) names AMPK activators, PPARδ agonists and Rev-erbα agonists but not ERR agonists. S0 bans any substance not covered by another section that has no current approval by any government health authority for human therapeutic use, and SLU-PP-332 is an experimental compound with no such approval. Anti-doping laboratories in Los Angeles and Cologne have already published methods to detect it.
- Last reviewed
- 2026-10
Grade D · Animal data only
Why this grade
Every effect comes from mice and from cells in lab dishes. It has never been given to people in a published or registered trial, so there is no human data on whether it works or is safe.
What is it?
Why people buy it
People buy it to lose fat and build stamina without extra exercise. Sellers call it 'exercise in a pill'.
What we actually know
- •It is not a peptide. It is a small man-made chemical, but peptide shops sell it.
- •In mice, it made muscles act more like they had been exercised. The mice ran further.
- •In fat mice, it cut fat gain and improved blood sugar control. In sick mice, it helped the heart.
- •It has never been tested in people. It is not a licensed medicine in the UK, or anywhere else.
What might happen
- •There is no proof it burns fat or builds fitness in people.
- •Nobody knows the side effects or long-term risks in people. There is no safety data.
- •It switches on many genes in muscle, heart and other organs. What that does over years is unknown.
- •It is sold online as 'not for human use'. Nobody checks what is really in the bottle.
- •In sport, it is banned at all times. Unapproved drugs count as banned. Drug-testing labs can already detect it.
Bottom line
Impressive in mice. In people, it is an untested chemical, not a shortcut to fitness.
Know someone taking this?
Send on WhatsAppIt is like a remote control that flips a mouse's muscles into 'just been for a run' mode. In mice, the screen changes. Nobody has pointed it at a person, and nobody knows what else the same button switches on.
How is it meant to work?
SLU-PP-332 binds and activates the oestrogen-related receptors ERRα, ERRβ and ERRγ, nuclear receptors that act as master switches for genes involved in fatty-acid burning, mitochondrial function and oxidative metabolism. By activating ERRα in particular, the compound switched on part of the acute aerobic exercise gene program in mouse muscle, shifting fibres toward the oxidative type and increasing endurance. In the heart, ERRγ appears to be the main driver of the protective effects seen in mice. The ERRs are not classic oestrogen receptors and SLU-PP-332 is not a hormone.
What's it studied for?
Research contexts. Not proven uses, and not recommendations.
Does the human evidence stack up?
None in living people. No trial of SLU-PP-332 is registered on ClinicalTrials.gov or published. The closest thing is a 2025 study that took muscle biopsies from 20 women having hip replacements, grew muscle cells from them in the lab and treated those cells with SLU-PP-332; no one was given the drug. Anti-doping labs have studied how human liver fractions break it down in a test tube, purely to detect misuse. Claims that it burns fat or boosts fitness in people are extrapolated from mice.
What could go wrong?
- !No human safety or dosing data exist, so side effects and long-term risks are unknown.
- !ERRs control large networks of metabolic genes in muscle, heart, kidney and other tissues; switching them on body-wide for long periods has not been studied in humans.
- !Its developers described it as an in vivo chemical tool. No human toxicology or dose-finding work has been published.
- !Grey-market products are unregulated, so identity, purity and strength are unverified.
- !Marketed as 'exercise in a pill', which overstates mouse results and implies a benefit never shown in people.
- !Founding researchers declared a commercial interest in ERR-based therapeutics.
Is it legal in the UK?
SLU-PP-332 is not a licensed medicine in the UK and has no MHRA marketing authorisation for any condition. It is not a controlled drug. Products sold online are unlicensed research chemicals, typically labelled 'not for human consumption' to sidestep the Human Medicines Regulations 2012; selling or promoting it as a treatment for people would breach those rules. There is no lawful route to obtain it in the UK as a medicine.
Sources
- 01Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity — Billon C, Sitaula S, Banerjee S, et al. (Burris TP senior author), ACS Chemical Biology (2023)
Founding paper: cell and mouse work showing more oxidative muscle fibres and longer endurance in mice. Authors declared stock in Myonid Therapeutics.
- 02A Synthetic ERR Agonist Alleviates Metabolic Syndrome — Billon C, Schoepke E, Avdagic A, et al., Journal of Pharmacology and Experimental Therapeutics (2024)
Obese mouse models: more energy use and fat burning, less fat build-up, better insulin sensitivity. Mice only.
- 03Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function — Xu W, Billon C, Li H, et al., Circulation (2024)
Mouse heart-failure model. Mice only.
- 04Targeting ERRs to counteract age-related muscle atrophy associated with physical inactivity: a pilot study — Bonanni R, Falvino A, Matticari A, et al., Frontiers in Physiology (2025)
Muscle cells grown from biopsies of 20 women were treated in a dish. Nobody was given the drug.
- 05Analysis and Identification of In Vitro Metabolites of Exercise Mimetic SLU-PP-332 ERRα/β/γ Agonist for Doping-Control Purposes — Avliyakulov NK, Sobolevsky T, Ahrens E, Drug Testing and Analysis (2026)
UCLA Olympic Analytical Laboratory detection work using human liver fractions in a test tube. Shows anti-doping interest, not human dosing.
- 06SLU-PP-332 (PubChem compound record, CID 5338394), PubChem, US National Library of Medicine
Chemical identity: C18H14N2O2, molecular weight 290.3. Confirms it is a small molecule, not a peptide.
- 07World Anti-Doping Code International Standard: Prohibited List 2026, World Anti-Doping Agency (2026)
S0 non-approved substances and S4.4 metabolic modulators; ERR agonists are not named.
Related
Before you trust a vial
Peptides are freeze-dried for a reason. If you have seen SLU-PP-332 sold pre-mixed in a ready-to-use pen or syringe, here is why that is a red flag for potency, sterility and dosing.
Storage & stability →Stay posted
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