What it is
SLU-PP-332 is a synthetic small molecule, not a peptide. It was designed by Thomas Burris's research group in St Louis as a lab tool to switch on the estrogen-related receptors (ERRs), a family of three proteins (ERR alpha, beta and gamma) inside cells. It activates all three but is most potent at ERR alpha.
It shows up in this library because research suppliers list it next to peptides, and because it is heavily discussed as an "exercise mimetic". The evidence behind that label comes entirely from mice and cell cultures. There are no human trials.
How it works
Despite their name, ERRs are not activated by estrogen. They are orphan nuclear receptors: proteins that sit on DNA and turn on groups of genes, in this case genes that build mitochondria and run aerobic energy production. Genetic studies had already tied ERRs to muscle endurance, which made them an obvious target for a drug that might reproduce part of what training does.
The Burris group reported that SLU-PP-332 increased mitochondrial function and cellular respiration in a muscle cell line, then triggered an acute aerobic exercise gene programme in mouse muscle. Removing ERR alpha blunted the endurance effect, which suggests the compound works mainly through that receptor.
Compare MOTS-c, a mitochondria-derived peptide that is also studied for exercise-like metabolic effects, through a different pathway.
What the research found
Human studies
None. No clinical trial of SLU-PP-332 has been published, and no dose, safety profile or pharmacokinetics in people has been reported.
The closest thing is a 2025 pilot study in Frontiers in Physiology that took muscle biopsies from 20 older women having hip replacement surgery, grew the muscle cells in dishes, and added SLU-PP-332 to the culture for 48 hours. The authors reported lower oxidative stress markers and better formation of muscle fibres in the dish. Nobody received the compound; it is cell work using human tissue.
Animal and cell studies
- Exercise capacity (ACS Chemical Biology, 2023). In mice, SLU-PP-332 increased the proportion of type IIa oxidative muscle fibres, the fatigue-resistant type, and improved running endurance.
- Obesity and metabolic syndrome (JPET, 2024). In diet-induced obese mice and genetically obese ob/ob mice, it raised energy expenditure and fatty acid oxidation, reduced fat mass gain, and improved insulin sensitivity.
- Ageing kidney (American Journal of Pathology, 2023). In 21-month-old mice, eight weeks of treatment reversed age-related mitochondrial dysfunction and inflammation in the kidney, according to the authors.
These are small academic studies in which the mice were injected and treated for weeks. That is a normal early stage for a compound, and it is a long way from knowing whether a drug is safe or useful in people.
Side effects reported in studies
No human side effects have been reported because no humans have been studied. The mouse papers describe metabolic effects rather than a formal toxicology programme. Long-term effects of switching on mitochondrial gene programmes across the whole body are unknown.
Anyone reading supplier claims about SLU-PP-332 "dosing" in people should know those numbers do not come from any trial.
SLU-PP-332 vs other metabolic research compounds
| Compound | Type | Best evidence |
|---|---|---|
| SLU-PP-332 | Small-molecule ERR agonist | Mice and cells |
| MOTS-c | Mitochondrial-derived peptide | Mostly animal |
| 5-Amino-1MQ | Small-molecule NNMT inhibitor | Mostly animal |
| SS-31 | Mitochondria-targeted peptide | Human trials |
For how these rank against compounds with human data, see best peptides for anti-ageing.
Status in the Philippines
SLU-PP-332 is not registered with FDA Philippines and is not approved as a medicine anywhere. It is sold online as a research chemical, and there is no published human data for any form of it. It is not a peptide, so peptide handling advice does not necessarily apply to it.
Storage
No manufacturer label exists. As a general rule for research chemicals, keep dry powder sealed, cool and away from light and humidity. Philippine heat and humidity are hard on unstable compounds, so a sealed container in the fridge is the conservative choice.
