Last updated: March 2026
SLU-PP-332 is an ERRα/ERRγ agonist developed at Saint Louis University that activates the transcriptional program of aerobic exercise training in skeletal muscle — without any actual exercise. In mice, it dramatically increases running endurance and shifts muscle fiber composition toward oxidative types. Whether it translates to humans remains completely unknown.
ERRα and ERRγ are orphan nuclear receptors — "orphan" because no natural ligand was initially known. They are master regulators of the gene programs that aerobic exercise activates. SLU-PP-332 is a synthetic agonist that hijacks these receptors to turn on those programs pharmacologically.
Estrogen-related receptors alpha (ERRα) and gamma (ERRγ) are transcription factors that control hundreds of genes involved in mitochondrial biogenesis, fatty acid oxidation, and oxidative phosphorylation. Regular aerobic exercise increases ERRα/γ activity — it's a core mechanism by which training adapts muscle. SLU-PP-332 directly activates these receptors, bypassing the need for physical exercise stimulus.
Skeletal muscle fibers come in two broad types: fast-twitch glycolytic (Type II, fatigue-prone) and slow-twitch oxidative (Type I, fatigue-resistant). Endurance training shifts muscle toward oxidative fibers. In the Schneeberger 2023 study, SLU-PP-332-treated mice showed increased Type I fiber content in multiple muscle groups compared to sedentary controls — a hallmark of aerobic training adaptation.
ERRα and ERRγ work closely with PGC-1α — the primary coactivator of mitochondrial biogenesis. SLU-PP-332 activation drives expression of TFAM, NRF1/NRF2, and electron transport chain components, increasing mitochondrial density in muscle cells. More mitochondria = greater aerobic capacity and fat oxidation capacity. This is the same pathway that endurance training activates over months of consistent work.
Transcriptomic analysis in the Schneeberger study showed SLU-PP-332 upregulated hundreds of exercise-responsive genes in skeletal muscle — including VEGF (blood vessel growth), MCT1 (lactate transporter), HADHA (fatty acid oxidation), and PPARGC1A (PGC-1α itself). The overlap with exercise-induced gene expression was substantial, explaining the functional phenotype observed in running tests.
All data below is from mouse studies. Human data does not exist. Bar widths represent relative magnitude of effect, not absolute percentages.
While SLU-PP-332 remains research-only, these tools support legitimate aerobic training optimization.
Dosing schedules, interaction warnings, and cycle protocols for 50+ compounds — all in one place.
This page is for educational purposes only. SLU-PP-332 is a research chemical with animal data only. It has not been tested in humans. No dose, safety profile, or efficacy claim can be made for human use. This is not medical advice. Do not self-administer this compound — human safety is completely unknown. The "exercise in a pill" framing is media shorthand for a preliminary animal study, not an established fact.