SLU-PP-332
A synthetic small molecule — not a peptide — that activates all three estrogen-related receptors, with the highest potency at ERRα. In mice it raised endurance, increased oxidative muscle fibres, reduced fat mass and protected failing hearts and ageing kidneys. It has never been given to a human in a published study, and its own developers report that it lacks oral bioavailability.
Reviewed & fact-checked by
BiohackingHub Research TeamEditorial Research Team · Last updated: October 3, 2026
Medical Disclaimer: The information on this page is for educational and research purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment.
What SLU-PP-332 Is — and Is Not
SLU-PP-332 is a synthetic small molecule designed to activate the estrogen-related receptors ERRα, ERRβ and ERRγ. Despite the name, these receptors do not bind oestrogen. They are orphan nuclear receptors that switch on the genes for mitochondrial biogenesis, oxidative phosphorylation and fatty acid oxidation, and they are essential for the way skeletal muscle adapts to aerobic training.
Two labels that travel with this compound need correcting. It is not a peptide — it is routinely sold alongside peptides and filed under the same heading, but it is a small molecule. And it is not a supplement — it is a laboratory tool compound from an academic drug-discovery programme, described by its authors as having "sufficient pharmacokinetic properties to be used as an in vivo chemical tool."
The Animal Evidence
Every result below is from mice or from cells.
| Model | Finding | Year |
|---|---|---|
| Healthy mice | More type IIa oxidative fibres, higher exercise endurance; effect required ERRα | 2023 |
| Diet-induced obese and ob/ob mice | Higher energy expenditure and fatty acid oxidation, less fat mass, better insulin sensitivity | 2024 |
| Pressure-overload heart failure | Better ejection fraction, less fibrosis, improved survival; mainly ERRγ-mediated | 2024 |
| 21-month-old mice, 8 weeks | Reversed age-related albuminuria, podocyte loss, mitochondrial dysfunction and inflammatory cytokines in the kidney | 2023 |
| Myoblasts from inactive women (in vitro) | Lower NOX4, higher SIRT1, PGC-1α and ERRα expression in cultured cells | 2025 |
That is a coherent preclinical story across muscle, fat, heart and kidney, published in ACS Chemical Biology, Circulation and the Journal of Pharmacology and Experimental Therapeutics. The 2025 study is the closest the literature gets to humans, and it is cells in a dish taken from surgical biopsies — not people taking the compound.
What SLU-PP-332 Has Never Shown
- Anything in a living human. No pharmacokinetic study, no safety study, no efficacy study. A 2026 systematic review of pan-ERR agonists covered animal and cell experiments only and concluded that clinical trials are needed.
- Oral activity. The developers' own 2026 paper states that SLU-PP-332 "lacks oral bioavailability" and introduces SLU-PP-915 as the orally active successor. Mouse studies used injection.
- Long-term safety. Published exposures run for weeks. Nobody knows what months of nuclear-receptor activation does to a heart, a liver or a tumour.
- A human dose. Any milligram figure on a vendor page is a guess scaled from mice.
The oral-bioavailability point is the practical one. Oral capsules are a common grey-market format. The people who invented the compound say that route does not deliver it.
Doping Status
The World Anti-Doping Agency prohibits exercise mimetics and metabolic modulators, and substances with no regulatory approval for human use are prohibited at all times. In 2026 two anti-doping laboratories independently published the compound's metabolite profile — one identified nine metabolites, the other twenty-two — explicitly to detect misuse. A tested athlete should treat SLU-PP-332 as detectable and prohibited.
Why It Is Graded D and Tier D
Grade D is the site's label for mechanism and animal evidence only, and SLU-PP-332 fits it exactly. The safety tier is also D, the lowest, and that is unusual: it is reserved here for compounds with no human safety data at all, sold without oversight, where the route of administration people actually use is one the developers say does not work.
None of this is a verdict on the science, which is strong for its stage. It is a verdict on taking it.
Where It Belongs
On a watch list. If orally active ERR agonists reach human trials, they could matter for metabolic disease, heart failure and sarcopenia. The full reading of the 2023–2026 literature is in SLU-PP-332: The Exercise Mimetic Research Update.
It is deliberately not a step in the Mito-Peptide Advanced protocol. That protocol starts with the intervention the compound is trying to imitate — exercise — which activates the same receptors, in humans, with outcome data.
Related Research
Stacking Interactions
How SLU-PP-332 interacts with other compounds
Both carry the 'exercise mimetic' label through different routes — MOTS-c via AMPK, SLU-PP-332 via ERR nuclear receptors. No combination study exists, and neither has human intervention data
The earlier-generation exercise mimetic, an AMPK activator already named by anti-doping authorities. Same regulatory problem, older data
In mice, the related agonist SLU-PP-915 added to exercise training further raised Ddit4 and mitochondrial gene expression. This is the one combination with data — and exercise is the half that works in humans
Safety Profile — Tier D
High caution — significant risk potential
Contraindications
- ●Any human use — there is no published human pharmacokinetic, safety or efficacy study
- ●Competitive athletes — unapproved substances are prohibited at all times and anti-doping laboratories have published its metabolite profile for testing
- ●Pregnancy and breastfeeding — no data in any relevant model
- ●Heart, liver or kidney disease — the mouse organ data cannot be read across to a diseased human organ on an unvalidated product
Side Effects
- ●Unknown in humans — no administration study exists
- ●Long-term effects of chronic nuclear-receptor activation are unstudied; the longest published mouse exposures run for weeks
- ●Grey-market capsules and liquids have no regulatory verification of identity, dose or purity