Ask most people what SLU-PP-332 is and you'll get some version of "a new exercise-mimetic peptide". That answer is wrong in the first and most important word. So the honest starting point for anyone doing SLU-PP-332 research — or wondering about SLU-PP-332 in Australia — is this: it is not a peptide at all. It is a 290-dalton synthetic small molecule with no amino acids and no peptide bonds anywhere in its structure. The mislabelling isn't pedantry. It changes what the compound does inside a cell, how the body clears it, why it can't simply be swallowed, and which shelf of the Australian regulatory system it sits on.

This piece is a myth-versus-evidence breakdown of the identity question, and what follows from getting it right. Our full profile sits at /peptides/slu-pp-332.

What is SLU-PP-332, chemically?

SLU-PP-332 has the molecular formula C18H14N2O2 and a molecular weight of about 290 g/mol, registered under CAS 303760-60-3. Its systematic name is 4-hydroxy-N'-(naphthalen-2-ylmethylidene)benzohydrazide — in plain terms, a naphthalene ring joined to a hydroxybenzoyl group through a hydrazone linkage. It belongs to a chemical class called acylhydrazones.

Compare that with an actual peptide. Retatrutide is a 39-amino-acid chain more than ten times heavier, built from residues strung together by peptide bonds and folded into a shape that docks onto receptors on the outside of a cell. SLU-PP-332 shares none of that architecture. The only thing it genuinely shares with peptides is a distribution channel: it arrives in the same lyophilised vials, from the same research-chemical suppliers, filed on the same websites. That's a marketing accident, not a pharmacological category.

Why the "peptide" label sticks

Three reasons, none of them scientific. It's sold alongside peptides. It's dosed in micrograms and reconstituted like one. And the phrase "exercise mimetic" has been absorbed into peptide-forum vocabulary, where SLU-PP-332 is discussed next to compounds that really are peptides. Our broader peptides index keeps the distinction explicit for exactly this reason.

Why the distinction actually changes things

It works inside the nucleus, not on the cell surface. SLU-PP-332 is a pan-agonist of the estrogen-related receptors ERRα, ERRβ and ERRγ — orphan nuclear receptors that act as transcription factors governing mitochondrial and oxidative gene programmes. In the 2023 characterisation published in ACS Chemical Biology, the compound raised mitochondrial respiration in skeletal myoblasts and drove an ERRα-dependent transcriptional response in mice that resembled the response to acute aerobic exercise. That is a gene-expression mechanism. Peptide therapeutics almost never work this way; they are too large and too charged to drift into the nucleus and grip a receptor's ligand-binding pocket.

It is cleared by liver enzymes, not peptidases. Peptides are broken down by proteases and typically have half-lives measured in minutes unless deliberately engineered otherwise. A small molecule like SLU-PP-332 goes through hepatic phase I and phase II metabolism instead. That difference is why anti-doping laboratories in 2026 approached it as a small-molecule mass-spectrometry problem — the detection story we covered separately — rather than a peptide-screening one.

And it explains the oral problem. Peptides usually fail orally because the gut digests them. SLU-PP-332 fails orally for a different reason: poor oral bioavailability driven by its own pharmacokinetics. In the mouse work it was given by intraperitoneal injection, typically twice daily. Fixing that required chemistry, not a protease-resistant redesign — and that is precisely what the successor compound is.

The successor: SLU-PP-915

In 2025–26 the Saint Louis group published SLU-PP-915 in the Journal of Pharmacology and Experimental Therapeutics: a chemically distinct pan-ERR agonist that is, per the authors, the first of the series with meaningful oral bioavailability. In run-to-exhaustion treadmill testing, both compounds pushed treated mice roughly 50% beyond vehicle controls for maximal running time and distance — but SLU-PP-915 achieved it at less than half the dose, and held comparable efficacy when given orally once systemic exposure was accounted for.

Read that carefully, because it cuts against the marketing. The newer molecule is the one built to be swallowed. Anything sold as "oral SLU-PP-332" is working against the compound's own published pharmacokinetics. And every number above is from mice. There are no human efficacy data for either molecule.

Is SLU-PP-332 legal in Australia?

SLU-PP-332 is not listed in the Poisons Standard and has no entry on the ARTG. Unscheduled is not the same as approved, and it is nowhere near the same as lawfully supplyable — with no ARTG registration there is no lawful therapeutic supply pathway in Australia, and no approved indication a prescriber could write to.

A specific conflation worth killing: the TGA's scheduling decision for stenabolic (SR9009), finalised in 2018, covers synthetic REV-ERB agonists. REV-ERB and ERR are different nuclear receptor families with different ligands. That entry does not capture SLU-PP-332, and pointing at it either to claim the compound is banned or to claim it's been cleared gets the pharmacology wrong in both directions.

For athletes the answer is simpler and stricter. WADA's S0 category prohibits substances with no current approval by any governmental regulatory health authority for human therapeutic use, at all times, in and out of competition. SLU-PP-332 and SLU-PP-915 both sit squarely inside that description, and validated laboratory detection methods for them were published in 2026. Tested athletes should treat this as a closed question.

One more caution if you research this yourself: clinical trial registries now carry fictional demonstration records for various peptides and research compounds. Before you believe any "recruiting" listing, check that the sponsor is a real, verifiable organisation. For SLU-PP-332, the accurate statement remains zero human trials.

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FAQ

Is SLU-PP-332 a peptide?

No. It is a synthetic small molecule — an acylhydrazone with the formula C18H14N2O2 and a mass of about 290 g/mol, containing no amino acids or peptide bonds. It is commonly sold and discussed alongside peptides, which is where the confusion comes from.

Is SLU-PP-332 legal in Australia?

It is not scheduled in the Poisons Standard, but it has no ARTG registration and therefore no lawful therapeutic supply pathway in Australia. It is also prohibited for tested athletes under WADA's S0 non-approved-substances category.

What is the difference between SLU-PP-332 and SLU-PP-915?

Both are pan-ERR agonists from the same research group. SLU-PP-915 is chemically distinct, orally bioavailable, and in mouse treadmill testing matched SLU-PP-332's roughly 50% endurance gain at less than half the dose.

Are there any human trials of SLU-PP-332?

No. All published efficacy data come from rodent models, and no legitimate human trial of SLU-PP-332 has been registered or completed. Treat any registry listing as unverified until you have confirmed the sponsor is a real organisation.

Sources

This article is information only, not medical advice, and retatrutide.net.au is independent and not affiliated with any manufacturer. SLU-PP-332 is an unapproved investigational compound with no human trials and no approved therapeutic use in Australia or anywhere else.