SLU-PP-332

SLU-PP-332 is a synthetic small-molecule agonist of the estrogen-related receptors (ERR-alpha, ERR-beta, and ERR-gamma), a family of orphan nuclear receptors that act as master regulators of mitochondrial metabolism and the transcriptional response to exercise ^[1][3]. It was identified by the Burris laboratory and collaborators as a pan-ERR agonist with the greatest potency at ERR-alpha, a subtype that had long resisted drug development, and it is described in the literature as an exercise mimetic ^[1].

Its research applications cluster around metabolism, muscle, and endurance. In the foundational report, SLU-PP-332 increased mitochondrial function and cellular respiration in muscle cells, expanded oxidative type IIa muscle fibers, and enhanced running endurance in mice through an ERR-alpha-dependent acute aerobic exercise gene program ^[1]. Follow-on work showed that it alleviates metabolic syndrome in diet-induced obese mice, increasing energy expenditure and fatty acid oxidation while reducing fat mass and improving insulin sensitivity ^[2]. Medicinal chemistry has since mapped the structure-activity relationships of the scaffold to guide next-generation ERR agonists ^[3], and systematic reviews now treat it, alongside its successor SLU-PP-915, as a prototype exercise-mimetic strategy ^[4].

SLU-PP-332 is an investigational research compound with no regulatory approval and no human clinical use; it is not a supplement or medicine ^[1][3]. A practical limitation noted in later research is that it has poor oral bioavailability and has largely been dosed by injection in animal studies, which motivated the development of orally active analogues ^[4]. Because ERR agonists trigger physiological processes that resemble physical training, they are viewed as relevant to sports drug testing, and analytical methods for detecting SLU-PP-332 and its metabolites have already been reported ^[5].

There are no human safety data; SLU-PP-332 is preclinical only. Animal work has not flagged major toxicity, but its effects, dosing, and interactions in people are unknown. Research-only.

SLU-PP-332 was developed in the laboratory of Thomas Burris with collaborators spanning Saint Louis University, Washington University in St. Louis and the Salk Institute, emerging from a long effort to find a drug-like activator of the estrogen-related receptors. Genetic studies had shown ERRs to be essential for the muscle adaptations that improve exercise capacity, but they proved difficult to drug because they are constitutively active orphan receptors, and creating potency at the ERR-alpha subtype in particular had been a persistent obstacle.

The breakthrough was reported by Billon and colleagues in 2023 in ACS Chemical Biology, which identified SLU-PP-332 as the first synthetic pan-ERR agonist with its highest potency at ERR-alpha and showed it enhanced endurance in mice. A 2024 follow-up extended these findings to models of obesity and metabolic syndrome. It remains a preclinical compound with no human data.

SLU-PP-332 is celebrated as the founding compound of the estrogen-related receptor agonist class of so-called exercise mimetics, the molecule often credited with opening the door to pharmacologically capturing benefits of aerobic training. Its appeal is genuinely striking; by switching on the nuclear receptors that master mitochondrial metabolism, it induced a transcriptional state resembling acute exercise, boosting endurance, oxidative muscle fibers, energy expenditure and fat oxidation in animals without relying on stimulant-style central nervous system arousal.

Because it engages the physiological machinery of endurance rather than appetite suppression, it has attracted intense interest for obesity and metabolic health. The important caveat is that all of this remains in cells and rodents; there are no human efficacy or safety data yet, so its promise, while real, is unproven in people.