SLU-PP-332
ERR agonist, exercise mimetic
A pan-ERR agonist that reproduces some of exercise's metabolic signalling in mice. Genuinely novel pharmacology, zero human data, and sold anyway.
Preclinical only
Not approved anywhere and not in human trials. A laboratory tool compound from academic drug discovery, sold online as research material.
What it is
Oestrogen-related receptors are nuclear receptors that, despite the name, do not bind oestrogen. They regulate mitochondrial biogenesis and oxidative metabolism, and they are among the transcriptional programmes that endurance exercise activates in muscle.
SLU-PP-332 is a synthetic agonist that activates all three subtypes. In mice it increases exercise capacity, shifts muscle toward oxidative fibre types, raises energy expenditure and produces weight loss without reduced food intake. It came out of academic drug discovery at Saint Louis University, which is where the name comes from.
Why this entry exists at all
Because it is being sold, and because it is the clearest current example of a laboratory tool compound leaking into consumer use.
There is no phase 1 trial. There is no human pharmacokinetic data. There is no established dose, route or duration. The compound was designed as a probe to interrogate ERR biology, and the published work since has been about chemically optimising it, which is what you do with a lead compound rather than a finished drug.
The doses circulating in online protocols are back-calculated from mouse studies. Scaling between species is not a matter of adjusting for body weight, and treating a rodent dose as a human dose is one of the more reliable ways to get hurt by a novel compound.
The mechanism cuts in an uncomfortable direction
ERRs are highly expressed in cardiac muscle, where they regulate the mitochondrial capacity the heart depends on. That is part of why the biology is interesting.
It is also why a pan-agonist deserves more caution than an untested peptide with a vague mechanism. This compound acts on transcriptional programmes in the heart, and nobody has looked at what sustained activation does there in a human.
Practical notes
- Exercise mimetic is a description of a signalling pathway, not a promise. Activating some of the transcriptional consequences of exercise is not the same as obtaining the benefits of exercise, which include cardiovascular, skeletal and neurological adaptations this compound does not touch.
- Preclinical here means early preclinical. Even within this site's lowest evidence tiers, there is a difference between a compound with decades of animal work and one still being chemically optimised in the literature.
- Purity is unverifiable and matters more than usual. For a novel small molecule with no reference standard in circulation, a buyer has no practical way to establish that a vial contains what the label says.
Side effects and warning signs
Commonly reported
- Unknown in humans. No clinical safety study has been conducted
- Rodent studies report reduced food intake and weight loss, which are effects rather than a safety profile
Stop and get medical help
- Oestrogen-related receptors are expressed throughout cardiac and skeletal muscle. A pan-agonist acting on all three subtypes has cardiac exposure that has never been characterised in a person
- Any cardiac symptom during use, given the above and the complete absence of human safety data
Sources
From the community
Discussion for this compound concentrates in r/Biohackers.
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