SLU-PP-332 side effects by evidence tier: no human data of any kind, what the short mouse studies did and did not measure, the cardiac and carcinogenicity questions, and Canadian and WADA status.
SLU-PP-332 is not a peptide. It is a synthetic small molecule that activates the three oestrogen-related receptors — orphan nuclear receptors that control the genes for mitochondrial biogenesis and fatty-acid oxidation in muscle and heart — and it became widely known in 2023 when two papers from one laboratory reported that it made mice run further and lose fat. A side-effects page for it is short on findings and long on gaps, and that asymmetry is the content: the compound has never been given to a human in a published study, so every tier of evidence above "short mouse experiments" is empty. This page is a research reference, not advice.
The SLU-PP-332 profile is the reference entry and the SLU-PP-332 research overview covers the receptor biology.
There is no human safety dataset for SLU-PP-332. No pharmacokinetic study, no single-ascending-dose study, no tolerability study, no registered clinical trial anywhere. No company has announced development toward an indication. The compound has been a tool for asking what happens when the ERRs are pharmacologically activated, and that question has only been asked in cells and mice. Any claim about how SLU-PP-332 is "tolerated" in people has no source.
The published record is two 2023 papers from Thomas Burris's group: the exercise-capacity study in ACS Chemical Biology and the companion metabolic-syndrome study in the Journal of Pharmacology and Experimental Therapeutics. Both gave 50 mg/kg by intraperitoneal injection twice daily in a DMSO-containing vehicle for roughly two to four weeks, and both tracked body weight and food intake. The authors reported no overt toxicity over that period. Fat mass fell and energy expenditure rose in obese mice with food intake unchanged, which is a pharmacological finding rather than an adverse one.
What was not done matters more. No formal toxicology was published — no dose-ranging for adverse effects, no organ histology as a safety endpoint, no clinical chemistry panel, no cardiac assessment and no exposure beyond a few weeks. No second species was used. Reproductive, developmental and genotoxicity work does not exist. The mouse data therefore supports one narrow sentence: at one regimen, for a few weeks, mice did not show obvious harm. It does not support "no side effects".
Three follow directly from the biology, and none has been tested.
The heart. ERRs are abundantly expressed in cardiac muscle, where they control the mitochondrial program the heart runs on. Chronic pharmacological activation could in principle be beneficial or harmful there and no study has asked which. A compound designed to remodel muscle metabolism will remodel the heart's, and the mouse work measured skeletal-muscle endpoints.
Proliferation and carcinogenicity. Sustained transcriptional activation of a growth-adjacent program is a general concern for nuclear-receptor agonists. The precedent is specific: the PPARδ agonist GW501516, labelled an exercise mimetic in the same 2008 Cell paper that framed the field, was abandoned after rodent carcinogenicity findings at high doses. Nothing about SLU-PP-332 has been tested against that possibility, and a few weeks in mice could not detect it.
The vehicle. The compound is lipophilic and poorly soluble in water; every published study dissolved it in DMSO. DMSO is pharmacologically active in its own right, and any reported reaction to SLU-PP-332 outside a laboratory cannot be separated from the solvent used to deliver it.
Because the compound reached the research market within a year of the first paper, uncontrolled reports exist without any controlled baseline at all. They describe increased body temperature or sweating, insomnia, elevated heart rate and gastrointestinal upset. These are unblinded self-reports with no denominator, no confirmation of what was taken or in what solvent, and no way to separate compound from vehicle from expectation. The pattern of compounds sold as exercise mimetics is instructive: GW501516 was sold online for years on the strength of rodent performance data despite its carcinogenicity findings. SLU-PP-332 is at exactly that point.
For a small molecule the analytical picture is purity by HPLC and identity by mass spectrometry or NMR; there is no peptide-content or counter-ion figure. Because the mouse doses were tens of milligrams per kilogram, a vial is a bulk-chemical quantity, and impurities that would be trivial at microgram scale — synthesis intermediates, residual solvents — are present in milligram amounts. Any reaction reported in unregulated use can trace to those, or to material degraded by moisture in a repeatedly opened DMSO stock, rather than to the molecule. A certificate of analysis is the only way to separate compound effects from product effects; lab testing and COAs describes what each lot is tested for.
SLU-PP-332 has no Health Canada market authorisation, no DIN and has never been submitted to any regulator; it is not a controlled substance, and the research-grade SLU-PP-332 sold here is supplied under research-use-only terms for laboratory work. Because it is a small molecule rather than a peptide, it was not part of the 2023 FDA section 503A bulk-substance evaluation; its status there is simply "not reviewed". It is not named on the WADA Prohibited List, but section S4.4, metabolic modulators, prohibits AMPK activators and PPARδ agonists by name as exercise mimetics and is worded to include related substances. An ERR agonist studied explicitly as an exercise mimetic is very likely to be treated as prohibited, and tested athletes should assume it is.
What side effects does SLU-PP-332 have? None are documented, because no study has looked. The two 2023 mouse papers reported no overt toxicity over a few weeks at 50 mg/kg twice daily, tracked body weight and food intake, and published no formal toxicology. There is no human data of any kind.
Has SLU-PP-332 been tested in humans? No. There is no pharmacokinetic study, no tolerability study and no registered clinical trial. It has never been administered to a person in a published study.
Is the cancer concern established? No, and neither is its absence. The concern is a class inference from nuclear-receptor pharmacology and from the related exercise mimetic GW501516, which was abandoned after rodent carcinogenicity findings. SLU-PP-332 has not been tested for carcinogenicity at all.
Why does the heart come up? ERRs are highly expressed in cardiac muscle and control its mitochondrial metabolism. A compound that activates them will act on the heart, and the mouse studies measured skeletal muscle, not cardiac function.
Is SLU-PP-332 prohibited in sport? Not by name, but WADA's S4.4 category prohibits AMPK activators and PPARδ agonists as exercise mimetics and covers related substances. Tested athletes should treat it as prohibited.
Is this medical advice? No. This page summarises the published mouse research and the absence of human data, for laboratory reference. SLU-PP-332 is sold here as a research-grade material, not for human or veterinary use, and nothing above is a safety assurance or a dosing recommendation.
