A research chemical that switches on the estrogen-related receptors, the gene switches muscle uses to adapt to endurance exercise. In mice it raised endurance, burned fat, and protected the heart and aging kidneys, but it has never been given to a human in a published study. Anti-doping laboratories already treat it as a doping agent.
SLU-PP-332 activates all three estrogen-related receptors, ERRα, ERRβ, and ERRγ, with the strongest effect on ERRα. Despite the name, these are orphan nuclear receptors, gene switches that turn on mitochondrial biogenesis, fatty acid oxidation, and oxidative phosphorylation, the machinery that lets muscle burn fuel for endurance. In muscle cells the compound increased mitochondrial function and cellular respiration. In mice it triggered the same gene program that an acute bout of aerobic exercise does, and that program depended on ERRα.
Injected under skin (1/6)
SLU-PP-332 is injected, because it is poorly absorbed when swallowed.
Because ERRs sit in heart, muscle, liver, and kidney, switching them all on has effects far beyond muscle. In a mouse heart failure model, the compound improved ejection fraction, reduced fibrosis, and increased survival, with ERRγ doing most of the work in the heart. In 21-month-old mice, 8 weeks of treatment reversed age-related protein leak into the urine and kidney inflammation. Human liver enzymes break it down into at least 22 metabolites in the test tube, which is how anti-doping labs plan to detect it, but no one has measured what it does in a living person.
SLU-PP-332 is sold online as an exercise mimetic, a compound meant to reproduce some of the benefits of aerobic training without the training. In mice it increased the share of oxidative muscle fibers and let the animals run farther, and in obese mice it raised energy expenditure and fat burning, cut fat mass, and improved insulin sensitivity. Other mouse studies reported better heart function in a heart failure model and reversal of age-related kidney inflammation. Every one of these findings comes from animals or cells.
It was developed as a laboratory tool by an academic group, and no company is seeking approval and no human trial is registered. The original compound lacks oral bioavailability, which is the stated reason its makers designed a successor, SLU-PP-915. Products sold online as research chemicals carry no verification of identity, purity, or dose. Doping-control laboratories have published methods to detect it, so tested athletes who use it can be caught.
The evidence is entirely preclinical. The founding paper showed enhanced exercise endurance and an ERRα-dependent exercise gene program in mice, a second paper showed less fat mass and better insulin sensitivity in diet-induced obese and ob/ob mice, a heart study showed protection against pressure-overload heart failure, and a kidney study treated 21-month-old mice for 8 weeks. Most of this work comes from the laboratory that designed the compound. The 2026 papers add only test-tube metabolism data gathered for doping control.
Nothing is known about human dose, absorption, or tolerability, so doses circulating in online communities are guesses scaled from mice. Independent replication outside the originating group is limited, and no long-term animal toxicity study has been published. Whether chronic activation of all three ERRs is safe for the heart is untested. The first human data of any kind would be a safety and pharmacokinetic study, and none is registered.
No human side effects are known, because no human study exists. The mouse studies were short and were designed to measure benefit rather than harm, so they say little about long-term safety. Chronic activation of nuclear receptors that control metabolism in the heart, liver, and kidney has no safety record in people. Anyone taking it is also taking an unverified product of unknown purity.
No regulator has approved this compound, and no company is seeking approval.
SLU-PP-332 is not approved by the FDA or any other regulator, and no human trial is registered anywhere. It is sold as a research chemical, a label that places it outside drug quality controls. The World Anti-Doping Agency prohibits exercise mimetics and metabolic modulators in sport, and laboratories have published detection methods for this compound specifically. It should not be confused with any approved drug.