SLU-PP-332: Evidence, Mechanism, Dosing & Legal Status

SLU-PP-332 is a synthetic pan-agonist of the estrogen-related receptors developed in Thomas Burris's laboratory (Saint Louis University / Washington University) as a chemical 'exercise mimetic,' and it is aggressively marketed as 'exercise in a pill' to the endurance, fat-loss and longevity audience.1 Despite being cross-listed in peptide libraries and sold through 'metabolic peptide' vendors, it contains no amino-acid chain and no peptide bond — its true taxonomic home is adjacent compounds.6 This monograph separates the elegant preclinical science from the marketing.

This article is informational and editorial content for research and educational purposes only. It is not medical advice, not a protocol to follow, and not a sourcing guide. SLU-PP-332 is an unapproved investigational research compound with zero published human trials; it is sold as a 'research chemical not for human use' and is functionally banned in sport. Dosing figures are reported strictly as seen in the preclinical literature for completeness — not as recommendations. Consult a licensed clinician before considering any experimental compound.

What is SLU-PP-332 and how does it work?

Chemically, SLU-PP-332 is a synthetic N-acylhydrazone: a 4-hydroxyphenyl ring and a naphthalen-2-yl ring joined by a hydrazone linker (C18H14N2O2; MW ~290.3 g/mol; CAS 303760-60-3; PubChem CID 5338394).6 The naphthyl group enables pi-pi stacking with Phe328 in the ERRalpha ligand-binding domain and the carbonyl is indispensable for activity — replacing it with a sulfonyl abolishes function.4 It is a small organic molecule, not a polypeptide.

The mechanism — all of it preclinical — centers on the estrogen-related receptors. ERRalpha, ERRbeta and ERRgamma are orphan nuclear receptors and master transcriptional regulators of mitochondrial biogenesis, oxidative phosphorylation, the TCA cycle and fatty-acid beta-oxidation, highly expressed in energy-demanding tissues such as skeletal muscle, heart, brown fat and kidney.1 They are normally driven by the coactivators PGC-1alpha/beta rather than a classic endogenous ligand and sit at the heart of the transcriptional response to endurance exercise. SLU-PP-332 is an agonist that pushes ERR transcriptional activity above its already-high constitutive level, switching on an ERRalpha-dependent acute aerobic-exercise gene program in skeletal muscle — upregulating fatty-acid-oxidation genes, electron-transport-chain components and oxidative-fiber specification (including Ddit4, Slc25a25 and Pdk4) and increasing cellular respiration.1 It thereby mimics the molecular signature of endurance exercise without muscle contraction.

In HEK293 reporter assays it activates all three ERRs with EC50 around 98 nM (ERRalpha), 230 nM (ERRbeta) and 430 nM (ERRgamma) — a pan-agonist with modest ERRalpha preference — and its exercise-program effect is superior to known PPARdelta (GW501516) and REV-ERB (SR9009) ligands.31 The compound is, however, poorly drug-like: very low kinetic solubility (~0.2 micromolar), high lipophilicity (cLogP ~4.05) and a short human-liver-microsome half-life (~31 minutes), with no oral-bioavailability and no human pharmacokinetic data. The PubChem record (PubChem CID 5338394) catalogs it strictly as a research chemical.46

What is the evidence by indication?

Every indication below rests on mouse and/or in-vitro data only. There are no human RCTs and no human cohort, observational or open-label efficacy data for SLU-PP-332 in any indication. The highest defensible grade is C across the board.5

The foundational in-vivo study showed that a single 25 mg/kg intraperitoneal dose induced the acute aerobic-exercise transcriptional program within hours, increased type IIa oxidative muscle fibers, and enhanced treadmill exercise capacity in untrained mice (roughly 45% greater running distance versus vehicle) — an effect absent when ERRalpha was removed.1 In diet-induced-obese and ob/ob mice dosed at 50 mg/kg, treatment increased whole-body energy expenditure and fat oxidation, reduced fat-mass accumulation (about 12% body-weight loss), produced a more oxidative muscle phenotype and improved insulin sensitivity — recapitulating exercise-like metabolic benefits without exercise.2 In a mouse transverse-aortic-constriction model of reduced-ejection-fraction heart failure, SLU-PP-332 improved ejection fraction and contractile function, reduced cardiac fibrosis and increased survival, with cardioprotection mediated specifically through ERRgamma.1

The 'longevity' claim rests on a single aging-kidney study: ERRalpha/ERRgamma expression declines in aging human and mouse kidneys, and treating 21-month-old mice (roughly a 70-year-old human equivalent) at 25 mg/kg/day for 8 weeks reversed age-related albuminuria, podocyte loss, mitochondrial dysfunction and inflammatory cytokines via the cGAS-STING/STAT pathways — mimicking effects otherwise seen with caloric restriction.3 This is a single-lab rodent finding with no human data; the broader human longevity claim is grade D.

What doses appear in the literature?

Reported strictly as information, not a protocol. The only controlled dosing is preclinical: a single 25 mg/kg intraperitoneal dose induced the muscle exercise-gene program, and 25-50 mg/kg intraperitoneal once or twice daily (DMSO vehicle) was used over 8-10 weeks for chronic endurance, obesity, heart-failure and kidney studies in mice.12 Naive mg/kg-to-human allometric scaling is not clinically validated and must not be used to infer a human dose. Every in-vivo result used intraperitoneal injection; the compound's poor solubility and short half-life make oral dosing pharmacokinetically unproven, and the original team said the molecule must be redesigned before pill formulation.48 Consumer 'research-chemical' channels sell '5 mg vials' and capsules with invented subcutaneous or oral protocols that originate from vendor copy, not from any pharmacokinetic or efficacy study, and contradict the compound's actual injectable, low-bioavailability pharmacology. Because it is a small molecule rather than a lyophilized peptide, peptide reconstitution conventions do not properly apply.6

How safe is SLU-PP-332?

Human safety data are nonexistent: there is no published human safety, tolerability or pharmacokinetic study, so the human adverse-effect profile is genuinely unknown.5 Short mouse studies reported no severe adverse effects at effective doses, but they were not designed to detect chronic, carcinogenic, reproductive or off-target harm, and the developers explicitly called for more animal work before any move toward human trials.28 Several theoretical concerns dominate. ERRgamma is central to cardiac energetics; although SLU-PP-332 was cardioprotective in heart-failure mice, this same potency makes cardiac safety a priority unknown for chronic human use.1 As an agonist forcing ERR transcription above its high constitutive baseline across many tissues, chronic systemic activation could have unintended effects, and because ERRalpha is implicated in the metabolic reprogramming of several cancers, chronic pharmacologic ERR agonism is uncharacterized for oncologic risk. No human drug-drug-interaction or CYP studies exist — interactions are unstudied, not excluded.5 Pregnancy and lactation are precautionary contraindications, and as an unregulated research chemical sold 'not for human use,' products carry real risks of mislabeling, dosing errors and contamination.

What is the FDA and WADA status in 2026?

SLU-PP-332 is not an FDA-approved drug. There is no IND on the public record and no human clinical trial has been registered or completed; no SLU-PP-332 trial is listed on ClinicalTrials.gov as of June 2026.53 It is not an established 503A-compoundable or 503B bulk substance for human use, and it is sold illicitly as an unapproved 'research chemical' labeled 'not for human consumption.' Legitimate suppliers sell it strictly as a research reagent; human consumption is off-label experimentation with no safety floor.

For athletes the picture is unambiguous. SLU-PP-332 is not listed by name on the 2026 WADA Prohibited List, but it is a prototypical 'exercise mimetic' — the exact category named under S4.4 (Metabolic Modulators), which lists AMPK activators (AICAR, MOTS-c), PPARdelta agonists (GW501516) and REV-ERB agonists (SR9009) 'including but not limited to,' so a pan-ERR exercise mimetic is captured by that open class. As a non-approved substance it is also prohibited at all times under S0.7 Anti-doping laboratories have already published in-vitro metabolite characterization of SLU-PP-332 and its analog SLU-PP-915 specifically to develop pre-emptive doping-control assays, explicitly classifying them as exercise mimetics with doping potential.5 Any WADA-tested athlete should treat it as banned.

Bottom line. SLU-PP-332 is a mechanistically elegant small-molecule pan-ERR agonist that, in mice, reproduces a remarkable slice of the endurance-exercise phenotype. From a root-cause metabolic standpoint, targeting the master mitochondrial-biogenesis receptor is a far more upstream idea than stimulant thermogenics. But the honest evidence grade is C across the board: not a single registered, completed or published human trial; no human PK, safety or oral-bioavailability data; the only validated route is intraperitoneal injection in mice; and the compound itself is poorly drug-like. It is a promising preclinical tool compound and legitimate drug-discovery lead, but an unproven, unapproved and functionally doping-banned human 'supplement' — treat consumer products as experimental with an unknown safety floor.48