Most write-ups of SLU-PP-332 recycle the same two numbers: mice ran longer, mice got leaner. But if you read the actual papers in sequence, the most clinically serious dataset on this compound isn't about endurance or fat mass at all — it's about a failing mouse heart. And in that experiment, the receptor doing the work wasn't the one the "exercise in a pill" headlines named. This SLU-PP-332 research explainer walks through what is SLU-PP-332, why the heart data ran through ERRγ rather than ERRα, and where the compound actually sits for Australian readers.

What is SLU-PP-332? Start by deleting the word "peptide"

SLU-PP-332 is a synthetic small molecule developed out of Saint Louis University as a pan-agonist of the oestrogen-related receptors ERRα, ERRβ and ERRγ — orphan nuclear receptors that sit inside the cell and switch on genes for mitochondrial biogenesis, oxidative phosphorylation, fatty acid oxidation and the Krebs cycle.

It is not a peptide. It has no amino acid chain, it doesn't bind a cell-surface receptor, and it doesn't belong in the same pharmacological family as BPC-157 or tesamorelin. It is grouped with peptides purely because it circulates in the same "research compound" marketplace. If you've seen it described as a peptide — including on vendor pages that also list reconstitution instructions — that's a category error worth correcting before anything else. Our SLU-PP-332 profile keeps it filed with the other compounds we track in the peptides section for that reason, not because the chemistry fits.

The exercise paper: ERRα, acute response, mouse treadmills

The 2023 ACS Chemical Biology paper from the Burris group is the origin of nearly every claim you'll read online. In it, SLU-PP-332 induced an acute aerobic exercise gene program in mouse skeletal muscle, increased mitochondrial respiration in muscle cells, and improved running performance — the paper reports treated mice running roughly 70% longer in duration and about 45% further in distance. Crucially, the authors showed that response was ERRα-dependent: knock out ERRα, and the acute exercise signature largely disappears.

That's the paper behind the "exercise mimetic" label. It is a mouse study. It measures gene expression and treadmill output, not health outcomes, and it says nothing about whether a human would respond the same way.

The heart paper: same compound, different receptor

In 2024, a separate group published in Circulation using the mouse transverse aortic constriction (TAC) model — surgical pressure overload that drives the heart into failure over weeks. Both SLU-PP-332 and its structurally distinct successor SLU-PP-915 improved ejection fraction, reduced cardiac fibrosis, lowered the failure markers Nppa and Nppb, improved mitochondrial ultrastructure and improved survival — notably without changing cardiac hypertrophy. Metabolomics after six weeks of pressure overload showed substantial normalisation of fatty acid/lipid and TCA/oxidative phosphorylation metabolites.

Then comes the part that matters mechanistically. When the authors interrogated which receptor was responsible, siRNA knockdown of ERRγ — not ERRα, not ERRβ — abolished most of the compound-induced metabolic gene transcription in vitro.

So the same molecule appears to route through different ERR subtypes depending on tissue and context: ERRα for the acute skeletal-muscle exercise program, ERRγ for the cardiac metabolic rescue. That's a genuinely useful piece of pharmacology, and it also complicates the marketing story. "Pan-agonist" is not a detail you can wave away; a compound that activates three transcription factors across every tissue that expresses them has three separate dose-response curves to worry about, not one.

What the cardiac data does not establish

  • One animal model (TAC), in mice, from one research programme. No independent replication in the public literature that we can find.
  • A senior author on the cardiac work is disclosed as a co-founder of Pelagos Pharmaceuticals, which has an interest in ERR agonists. Disclosed conflicts aren't disqualifying, but they're context.
  • Reviews of this class explicitly flag undefined long-term safety, with pan-ERR activity raising theoretical concerns including hepatic effects — none of which has been characterised in humans.
  • Zero human trials. No Phase 1, no registered human study anywhere. If you encounter a trial registry entry suggesting otherwise, check the sponsor is a real organisation — registries carry demonstration records, and "recruiting" fictional sponsors have shown up for peptide-adjacent compounds.

The oral problem, and why SLU-PP-915 exists

SLU-PP-332 has poor oral bioavailability, which is why the animal work leans on injection. That limitation is the entire reason SLU-PP-915 was made. A December 2025 paper in the Journal of Pharmacology and Experimental Therapeutics reported that 915 is orally active and matches 332's effect on running distance and duration when given intraperitoneally, with comparable efficacy orally once systemic exposure is accounted for. Both compounds robustly induced Ddit4, an acute-exercise-responsive gene, at levels matching or exceeding treadmill running — and 915 appeared to add to, rather than replace, exercise training.

The practical read: if any compound in this family ever reaches a human trial, it's more likely to be 915 or a later analogue than 332 itself. Anyone buying 332 as "the oral exercise pill" has the wrong molecule for that claim.

Is SLU-PP-332 legal in Australia? The regulatory picture

SLU-PP-332 is not currently scheduled in the Poisons Standard. The commonly cited entry people point to — stenabolic/SR9009, added following a TGA final scheduling decision in April 2018 — covers REV-ERB agonists. That is a different receptor family entirely. It does not capture ERR agonists.

Unscheduled is not the same as available. There is no ARTG-registered SLU-PP-332 product, no approved indication, and therefore no lawful pathway for therapeutic supply in Australia. Anything sold here is positioned as a research chemical, outside any framework that verifies identity, purity or dose.

For anyone in tested sport, the position is unambiguous: WADA's S0 catch-all prohibits substances with no current regulatory approval for human therapeutic use, at all times, in and out of competition. That covers SLU-PP-332 and 915 by definition — and enforcement is no longer theoretical. Anti-doping laboratories published in vitro metabolite maps and detection methods for both compounds in 2026, including work in Rapid Communications in Mass Spectrometry. The window where this was undetectable has closed.

The honest summary

SLU-PP-332's most impressive dataset is cardiac, not cosmetic — improved ejection fraction and survival in pressure-overloaded mice, driven mainly through ERRγ. That's a real finding worth following. It is also mouse-only, single-model, unreplicated, from a programme with commercial interests, and attached to a molecule with poor oral bioavailability that a successor compound was built to fix. Everything downstream of that — dosing charts, "exercise in a pill" framing, endurance protocols — is extrapolation past the evidence.

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FAQ

What is SLU-PP-332?

SLU-PP-332 is a synthetic small molecule that activates the oestrogen-related receptors ERRα, ERRβ and ERRγ, increasing mitochondrial and fatty acid oxidation gene expression in mice. It is not a peptide, despite frequently being marketed alongside them.

Is SLU-PP-332 legal in Australia?

It is not currently scheduled in the Poisons Standard — the SR9009 entry covers REV-ERB agonists, a different family — but it has no ARTG registration and no lawful pathway for therapeutic supply, and WADA's S0 catch-all prohibits it in tested sport.

Has SLU-PP-332 been tested in humans?

No. As of September 2026 there are no completed or registered human trials of SLU-PP-332 at any phase; all published evidence is cell-based or in mice.

What's the difference between SLU-PP-332 and SLU-PP-915?

SLU-PP-915 is a structurally distinct pan-ERR agonist developed because SLU-PP-332 has poor oral bioavailability. A December 2025 mouse study reported 915 is orally active with comparable effects on exercise capacity.

Sources

This article is information only, not medical advice. SLU-PP-332 is an unapproved investigational compound with no human trials and no regulatory approval in Australia or anywhere else; retatrutide.net.au is independent and does not sell or source any compound.