What is SLU-PP-332?
SLU-PP-332 was developed in the lab of pharmacologist Thomas Burris at Saint Louis University, which is where the SLU in its name comes from. It is a synthetic small molecule, not a peptide. It was designed to activate a family of proteins called estrogen-related receptors, or ERRs, and it acts on all three types, with the strongest effect on ERR alpha.
Despite the name, ERRs are not estrogen receptors. They do not respond to estrogen, and SLU-PP-332 is not a hormone. ERRs are nuclear receptors, proteins that sit in the cell nucleus and control which genes are switched on. They are found at high levels in tissues that use a lot of energy, such as skeletal muscle, heart, kidney and brown fat.
How does SLU-PP-332 work?
ERR alpha and ERR gamma help turn on genes involved in making new mitochondria, using fatty acids for fuel and running aerobic metabolism. Exercise naturally increases the activity of this gene program in muscle. In mouse muscle and in cells, SLU-PP-332 increased the activity of many of the same genes and shifted muscle toward more fatigue-resistant fibers.
Researchers describe this as mimicking part of the response to aerobic exercise. That does not mean it reproduces exercise. Exercise affects the heart, lungs, bones, brain and many other systems in ways a single drug target cannot cover. How SLU-PP-332 behaves in the human body, including how it is absorbed and how long it lasts, has not been studied.
What has research looked at?
- Endurance in mice
- In a 2023 study, mice given SLU-PP-332 ran longer and farther on a treadmill than untreated mice, and their muscles showed signs of more mitochondrial activity.
- Obesity in mice
- In obese mice, researchers reported less fat gain, better insulin sensitivity and higher energy use.
- Heart
- In mouse models of heart failure, related ERR agonists including SLU-PP-332 were reported to improve heart function and energy metabolism in heart muscle.
- Aging kidney
- A study in aged mice reported that ERR activation improved markers of mitochondrial function and inflammation in the kidney.
- Brain
- Claims about brain protection are speculative. There is little published research on this.
These findings come from a small number of research groups, mostly working in mice. The studies are interesting but early, and no clinical trials in people have been published. Many compounds that look promising in mice never show the same effects in humans.
Is SLU-PP-332 a peptide?
No. SLU-PP-332 is a small synthetic molecule, much smaller than most peptides, and contains no chain of amino acids. It is often discussed alongside metabolic peptides such as MOTS-c because researchers study it for similar goals, such as energy use and metabolism. It also has nothing to do with estrogen, despite the name of the receptors it targets.
Side effects and cautions
Because there are no human studies, the side effects of SLU-PP-332 in people are unknown. The mouse studies were short and focused on effects rather than formal safety testing. Reports online of side effects such as feeling warm, a faster heart rate or stomach upset are anecdotal. Anyone with health questions should talk to a qualified clinician.
- Gene-level effects
- SLU-PP-332 changes the activity of many genes at once in several organs. The long-term effects of that are unknown.
- Cancer history
- Lab research has linked high ERR alpha activity to the growth of some cancers. Whether activating ERRs affects cancer risk in people is unknown.
- Pregnancy and breastfeeding
- There are no safety data, so this is an unknown.
- Product content
- Compounds sold outside medical settings can differ from their labels in content or purity.
Further reading
This page summarizes the research in plain words. To read the studies yourself:
- Published studies on SLU-PP-332 PubMed, US National Library of Medicine
