SLU-PP-332 Dosage & Dosing: Why It Is Not a Peptide, and Why Its Developers Say It Is Not Oral

SLU-PP-332 at a glance

It is not a peptide

SLU-PP-332 is a small synthetic molecule — PubChem CID 5338394, formula C18H14N2O2, molecular weight 290.3 g/mol, named 4-hydroxy-N-[(E)-naphthalen-2-ylmethylideneamino]benzamide. It contains no amino acids and no peptide bonds. For scale, the smallest genuine peptides in this library are several times its mass.

What it does

A pan-agonist of the estrogen-related receptors ERR-alpha, ERR-beta and ERR-gamma — orphan nuclear receptors that regulate mitochondrial biogenesis, oxidative phosphorylation, fatty acid oxidation and the Krebs cycle. It is described in the literature as an exercise mimetic and is widely used as a chemical probe for ERR activation.

The oral question, answered by its developers

The group that created it states it plainly: SLU-PP-332 'improves aerobic performance in mice but lacks oral bioavailability' (PMID 41421047). That sentence appears as the rationale for developing a different compound, SLU-PP-915, specifically to obtain an orally bioavailable ERR agonist.

Registered human trials

Zero. No study lists SLU-PP-332 as an intervention on ClinicalTrials.gov. The entire published record is cell-based and preclinical.

What the animal work measured

Increased aerobic exercise performance (distance and duration), induction of Ddit4 — a gene induced by acute aerobic exercise — at levels matching or exceeding treadmill running in some muscles, enhanced fatty acid oxidation, more type IIa muscle fibres, reduced adiposity, improved glycaemic control and increased basal energy expenditure in obesity models.

Route in the published work

Intraperitoneal injection is the route under which SLU-PP-332's exercise-mimetic effects were characterised in mice. The comparison compound SLU-PP-915 was the one shown to retain efficacy when given orally.

Reported range

No human dose is established. There is no human pharmacokinetic study, no dose-response data and no bioavailability figure for any route in humans. Every dosing figure in circulation is extrapolated from mouse work or invented.

Plasma half-life

Unknown in humans — no human pharmacokinetic study of SLU-PP-332 has been published, so any specific human figure is unsourced. What is documented is that the compound lacks oral bioavailability (PMID 41421047) and that analogues improved on its metabolic stability (PMID 41850449).

Known chemistry limitations

A systematic structure-activity analysis of the scaffold reports that while SLU-PP-332 remains a strong benchmark for ERR activation, several analogues achieve comparable transcriptional responses with improved ligand efficiency, solubility or metabolic stability (PMID 41850449) — i.e. the parent compound is the benchmark for potency, not for drug-like properties.

Reported ranges from research/community — examples, not recommendations.

What it is / mechanism

The estrogen-related receptors are orphan nuclear receptors — ERR-alpha, ERR-beta and ERR-gamma — and despite the name they are not estrogen receptors and do not bind estrogen. They are transcription factors that sit at the centre of the cell's oxidative-metabolism programme, regulating genes for mitochondrial biogenesis, oxidative phosphorylation, fatty acid oxidation and the Krebs cycle. They are also essential for how skeletal muscle adapts to aerobic exercise, which is the observation that made them a target in the first place. SLU-PP-332 is a synthetic pan-agonist: it activates all three. Because these are nuclear receptors rather than cell-surface receptors, the consequence of agonism is a change in gene transcription rather than a rapid signalling event, and that is exactly how the effect has been characterised. Pan-ERR agonists induce a gene-expression programme resembling acute aerobic exercise, dependent on ERR-alpha, including activation of Ddit4 and Slc25a25 (PMID 42024694). Ddit4 in particular is used as the readout throughout this literature because it is a gene induced by acute aerobic exercise, so its induction is a direct molecular comparison to the thing the compound is meant to mimic — and in the mouse work its induction matched or exceeded the levels produced by treadmill running, depending on the muscle examined (PMID 41421047). Downstream of the transcriptional programme, the reported physiology is coherent: enhanced fatty acid oxidation, an increase in type IIa muscle fibres — the oxidative-glycolytic fibre type that uses both fat and glucose — and improved endurance (PMID 42024694). One structural point belongs in the mechanism section because it explains most of the confusion around this compound. SLU-PP-332 is not a peptide and does not act like one. Peptides in this library act at cell-surface receptors and are destroyed by digestive proteases, which is why they are injected. SLU-PP-332 is a 290-dalton small molecule that must cross the cell membrane and reach a nuclear receptor to do anything at all. Those are different pharmacological problems, and the reason this compound is not oral is not the reason a peptide is not oral — it is a bioavailability property of this particular molecule, which its developers addressed by designing a different one.

Researched effects

Everything below was measured in cells or in mice. There is no human data of any kind. The exercise-mimetic finding is the core of the record. SLU-PP-332 improves aerobic exercise performance in mice — distance and duration — and robustly induces Ddit4, with induction matching or exceeding treadmill running in some muscles (PMID 41421047). A systematic review of the pan-ERR agonist literature from 2020 to 2024 summarises the wider picture: the compounds induce an acute-aerobic-exercise-like gene programme dependent on ERR-alpha, enhance fatty acid oxidation, increase type IIa muscle fibres and improve endurance; in obesity models SLU-PP-332 and SLU-PP-915 reduce adiposity, improve glycaemic control and increase basal energy expenditure, without evident toxicity, and effects on renal ageing and mitochondrial function have also been examined (PMID 42024694). That is a genuinely interesting preclinical package, and it deserves to be described as what it is rather than deflated for its own sake. ERR agonism produces a real, reproducible, exercise-associated transcriptional signature, and the endurance results in mice are not marginal. What the record does not contain is equally definite. No human trial exists — the ClinicalTrials.gov registry lists no study with SLU-PP-332 as an intervention. No human pharmacokinetic study, no dose-finding work and no bioavailability measurement in humans has been published. Body-composition and performance results in mice given intraperitoneal injections do not establish an effect in a person taking a capsule, and the compound's own developers identified the step where that inference breaks. The 'without evident toxicity' phrase from the review also needs reading precisely: it summarises preclinical models over their study durations, not human safety, and 'no evident toxicity in mouse obesity models' is not a safety finding about people.

Dosage — reported ranges (overview)

There is no established human dose for SLU-PP-332, and the reason is not that nobody has got around to it — it is that the compound has never been given to humans in a published study. That leaves every circulating figure in the same position: derived from mouse experiments, converted by some scaling rule, or simply asserted. Milligram-per-kilogram doses used intraperitoneally in mice do not convert cleanly to human amounts even for well-characterised drugs, because clearance, metabolism and body-surface-area scaling all differ; for a compound with no human pharmacokinetic data at all, the conversion has nothing to anchor to on the human side. The oral question deserves the most direct answer, because it is the most common one and it has a published answer. The laboratory that developed the compound wrote that SLU-PP-332 'improves aerobic performance in mice but lacks oral bioavailability', and stated it as the reason for developing SLU-PP-915 — a chemically distinct, orally bioavailable ERR pan-agonist (PMID 41421047). A daily oral figure for SLU-PP-332 therefore describes a route its developers went to the trouble of designing a replacement molecule to avoid. That is the single most useful thing on this page for anyone comparing capsule products. A second, quieter finding points the same way. The systematic structure-activity study of this scaffold reports that although SLU-PP-332 remains a strong benchmark for ERR activation, analogues were identified with improved ligand efficiency, solubility or metabolic stability (PMID 41850449). Read plainly: the parent compound is the reference standard for potency at the receptor, not for the properties that make a molecule behave predictably in a body. No amount, route or schedule is recommended here. The reported figures that circulate are noted as circulating; they are not endorsed, and no published human study supports any of them.

A printable protocol sheet with a reconstitution reference and an injection log comes with All-Access Lifetime.

Reconstitution — bac-water math

This section needs a caveat that does not apply to the peptides elsewhere in this library, and it follows directly from the compound's identity. The arithmetic is unchanged: concentration equals total compound divided by water volume, and on a U-100 insulin syringe 100 units equals 1 mL, so units to draw = (amount / concentration) x 100. The table below runs that arithmetic for a 10 mg vial and every row draws within a 1 mL syringe. What differs is the chemistry the arithmetic is being applied to. Lyophilised peptides are formulated to redissolve readily in aqueous solution, which is why bacteriostatic water is the standard diluent for them. SLU-PP-332 is a 290-dalton acylhydrazone with a naphthalene group — a small organic molecule rather than a peptide — and the published structure-activity work on this scaffold explicitly lists solubility among the properties that analogues improved on (PMID 41850449). Whether any given vial dissolves fully in water depends on how the supplier formulated it, and a calculation assumes a solution that is actually in solution: undissolved material means the concentration in the syringe is not the concentration in the table. Visible particulate or cloudiness after mixing is the relevant observation, and no arithmetic corrects for it.

This is concentration math, not a dose recommendation.

Injection / administration basics

The route used in the published work is intraperitoneal injection in mice — a laboratory route, not one used in humans for anything discussed here, and not one this page describes how to perform. It is stated because it is the route under which the compound's exercise-mimetic effects were characterised, and because it is part of why oral figures do not follow from that work. The distinction the literature itself draws is the useful one. SLU-PP-915 was developed and characterised precisely because it retains comparable efficacy when administered orally, adjusted for systemic exposure, while SLU-PP-332 does not have that property (PMID 41421047). Two compounds from the same programme, differing in the one respect that determines whether an oral product can work. No route, dose, frequency or schedule is recommended here.

Half-life & frequency rationale

No human half-life exists for SLU-PP-332, and no human pharmacokinetic study of any kind has been published — so any specific figure attributed to it in humans is unsourced. What the literature does say about its pharmacokinetic behaviour is indirect but pointed. The compound lacks oral bioavailability (PMID 41421047), and the structure-activity work on its scaffold identifies metabolic stability as one of the properties improved upon in analogues (PMID 41850449). Both statements describe a molecule whose exposure profile was a known limitation of the chemistry rather than a solved problem. There is also a conceptual point that matters more here than a clearance figure would. SLU-PP-332 acts on nuclear receptors by changing gene transcription, and transcriptional effects have their own timescale: the induction of a gene programme and the mitochondrial and fibre-type changes downstream of it persist on a biological schedule that is not the same as the compound's presence in plasma. Even if a half-life were published, it would describe how long the molecule lasts, not how long its transcriptional consequences do.

Stacking — overview

No study has examined SLU-PP-332 in combination with any other compound in humans, and the combinations discussed in communities are reasoning rather than measurement. One genuine combination result exists in the animal literature and is worth stating accurately because it concerns the sister compound: SLU-PP-915 synergises with exercise training to further enhance Ddit4 and mitochondrial gene expression (PMID 41421047). That is a drug-plus-training interaction in mice, reported for 915 rather than for 332, and it is the kind of detail that gets flattened into 'ERR agonists stack with training' when the specific compound and the specific readout are what make it meaningful. Stacks are described as reported practice, for educational purposes only. Nothing here is a protocol.

For how combinations are grouped by research context, the named blends, and why a pre-mixed blend vial cannot be calculated from its total milligrams, see the peptide stacks guide.

Storage & handling

• Store as the supplier specifies. This is a small organic molecule rather than a lyophilised peptide, so peptide storage heuristics are being applied by analogy, not from data about this compound.
• If supplied as a powder for reconstitution, refrigerated storage after mixing and protection from light are the standard precautions; avoid repeated freeze-thaw cycles.
• Bacteriostatic water contains 0.9% benzyl alcohol as a preservative, which is what permits multiple withdrawals from one vial; sterile water contains no preservative.
• Check for undissolved material before drawing. For a compound whose scaffold has documented solubility limitations (PMID 41850449), visible particulate means the concentration in the syringe is not the concentration on the label.
• Label the vial with the reconstitution date and the concentration — it cannot be recovered by looking at the vial.

Evidence File

The SLU-PP-332 Evidence File: No Trials, a Successor Compound That Tells You Why, and a Literature Now Written by Doping Labs

SLU-PP-332 has the strongest preclinical pedigree of any compound in this tranche — a 2023 origin paper, a 2024 paper in Circulation, an identified mechanism through the estrogen-related receptors, and an academic group actively publishing. It also has no clinical trials, no human data, and two features of its own literature that say more than any marketing page will. The first is that the laboratory behind it has moved on to a successor molecule described in its title as orally active, which tells you something about the original. The second is that the three most recent papers with this compound in the title are not about whether it works — they are anti-doping laboratories building assays to detect it. This file reads both signals carefully.

• 0 registered trials — checked under 3 named terms
• 10 PubMed records total; 3 with the compound in the title
• 2 of those 3 are doping-control detection papers
• A successor, SLU-PP-915, is described as "orally active" — this one is not

Sourcing File

The SLU-PP-332 Sourcing File: An Acylhydrazone That Can Fall Apart Into Two Pieces, and a Geometry Mass Spec Cannot See

SLU-PP-332 is chemically the least stable compound in this tranche, and the instability is structural rather than incidental. It is an acylhydrazone — two fragments joined by a bond that hydrolyses in acid and isomerises in light. This file works out exactly what it decomposes into and at what masses, so a reader can recognise degraded material on a certificate rather than trusting a purity figure. It also identifies a defect that no mass measurement can detect: the published structure specifies (E) geometry, and the (Z) isomer has an identical formula and an identical mass. As with the D-amino acid in another compound in this library, the analysis most certificates run is structurally incapable of asking the question.

• C18H14N2O2, MW 290.3 — computed independently, matches PubChem
• Hydrolyses into fragments at 156.2 and 152.2 Da
• (E) geometry specified; the (Z) isomer is identical by mass
• Neutral molecule — no counterion, so no salt-content correction

Benefit & Outcome Review

The SLU-PP-332 Benefit and Outcome Review: Good Science, Good Journals, No Humans

SLU-PP-332 has a better preclinical record than most compounds sold in this market — a defined molecular target, a clean origin paper, a publication in Circulation, and an active academic group. This review does not treat that as nothing. It does insist on the distinction that all four claims below turn on: the evidence is entirely in animals and cells, the compound has never been given to a human in a registered study, and its own laboratory has moved to a successor molecule. Each claim is graded on what was measured, in what species, and whether the result can be expected to survive the route of administration people actually use.

• 4 marketed claims assessed
• 0 supported by human data
• 3 have direct rodent evidence, one in a major cardiology journal
• 0 published oral bioavailability figures for this molecule

Guide FAQ

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