What Is SLU-PP-332? The ERR Agonist Explained

Cover illustration: AI-generated editorial artwork. Conceptual only; not an exact molecular structure, actual laboratory result or evidence of clinical effects.

SLU-PP-332 is a synthetic agonist of the three estrogen-related receptors, ERRa, ERRb and ERRg. It appears in research catalogues next to peptides, but it is not one: it is a small molecule, orally bioavailable in rodents, and it acts on nuclear receptors rather than a cell-surface receptor.

For laboratory research use only. The research materials supplied by HealthyWelness are not approved medicines, foods or cosmetics and are not for human or veterinary use. This article summarises published research and is not medical advice.

Key points

Class: small-molecule pan-ERR agonist, not a peptide.
Origin: developed at Saint Louis University (hence SLU).
Target: ERRa, ERRb, ERRg — orphan nuclear receptors, acting as transcription factors.
Published work: cell systems and mice; no human data located.
Handling: organic solvent stock, not a plain-water reconstitution.

What the ERRs actually are

The estrogen-related receptors were named for their sequence homology with the estrogen receptor. That name misleads newcomers: they do not bind estradiol and are not part of estrogen signalling. They are classed as orphan nuclear receptors because no endogenous ligand is firmly established.

What they do is act as transcription factors. ERRa in particular is a documented regulator of genes involved in mitochondrial biogenesis, fatty-acid oxidation and oxidative phosphorylation, working together with the PGC-1 coactivators. Because of that, the ERRs have been of interest for years as a pharmacological handle on oxidative metabolism — but for most of that time no usable synthetic agonist existed. SLU-PP-332 was reported as one of the first.

The published studies

Study	System	Reported finding
Billon et al., ACS Chem Biol 2023	Mouse skeletal muscle	Induced a transcriptional programme overlapping the acute aerobic exercise response; the effect was ERRa-dependent, and exercise capacity measures increased
Billon et al., JPET 2024	Mouse model of metabolic syndrome	Reported improvement in metabolic syndrome parameters following administration
Okda et al., Int J Biol Macromol 2026	Medicinal-chemistry series	Structural optimisation of the scaffold, used to probe ERR signalling further

Reading “exercise mimetic” carefully

The 2023 paper’s finding is specific and worth stating precisely: administration produced a transcriptional response in muscle that overlapped with the acute response to aerobic exercise, and this overlap was ERRa-dependent. That is a mechanistic result about gene expression in mice.

It is not a demonstration that the compound substitutes for exercise in any organism, and the authors did not claim it. Exercise produces cardiovascular, skeletal, neural and endocrine adaptations that no single transcription-factor agonist reproduces. When secondary sources compress the finding into “works like exercise”, a narrow and interesting result becomes an unsupported one.

Why the ERR target cuts both ways

Nuclear receptors regulate large gene sets, and the ERRs are no exception. A pan-agonist hitting all three subtypes acts across every tissue where they are expressed, which includes heart, kidney and brown adipose tissue, not only skeletal muscle. This is the standard trade-off in nuclear-receptor pharmacology: broad transcriptional reach is what makes the target attractive and what makes selectivity and tissue distribution the hard problems. The 2026 optimisation work exists precisely because the original scaffold left room on both counts.

Handling in the lab

Property	Note
Physical form	Powder, not a lyophilized peptide cake
Solubility	Poorly water-soluble; DMSO stocks are the usual route for cell work
Long-term storage	Sealed, desiccated, −20 °C, protected from light
Stock solutions	Aliquot DMSO stocks; avoid repeated freeze–thaw of a single tube
Identity check	Small-molecule methods — LC-MS, and NMR where available — rather than peptide mapping

One practical consequence: because this is not a peptide, bacteriostatic water is not a relevant diluent and peptide reconstitution tables do not apply. If a protocol asks for a molar concentration, work from the molecular weight on the certificate of analysis. For the peptides in a mixed study set, our reconstitution calculator covers that side.

Our SLU-PP-332 research material is supplied for laboratory research use. Certificates are available for listed products — contact us for the latest report.

Open questions

How does pan-ERR agonism compare with subtype-selective agonism on the same endpoints?
What is the chronic-exposure profile in cardiac tissue, where ERRa is highly expressed?
Does the transcriptional overlap with exercise persist beyond the acute window?

What is AICAR?
What is 5-Amino-1MQ?
What “research use only” means

Frequently asked questions

What is SLU-PP-332?

SLU-PP-332 is a synthetic small molecule that acts as an agonist at all three estrogen-related receptors (ERRa, ERRb and ERRg). It was developed at Saint Louis University, which is the source of the SLU prefix.

Is SLU-PP-332 a peptide?

No. Despite being catalogued alongside research peptides, it is a small synthetic molecule, not a chain of amino acids. It is orally bioavailable in rodents, unlike most peptides.

What are estrogen-related receptors?

ERRa, ERRb and ERRg are orphan nuclear receptors. The name reflects sequence similarity to the estrogen receptor; they do not bind estradiol. They act as transcription factors regulating genes involved in mitochondrial biogenesis and oxidative metabolism.

Why is it called an exercise mimetic in the literature?

A 2023 ACS Chemical Biology paper reported that the compound induced a transcriptional response in mouse muscle overlapping with the acute response to aerobic exercise, and that the effect depended on ERRa. The term describes an observed transcriptional overlap in mice, not an established equivalence.

Has SLU-PP-332 been studied in humans?

No human trial was identified in our literature search. The published work is in cell systems and rodents.

References

Billon C, et al. Synthetic ERRa/b/g Agonist Induces an ERRa-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity. ACS Chem Biol. 2023. PMID: 36988910 https://pubmed.ncbi.nlm.nih.gov/36988910/
Billon C, et al. A Synthetic ERR Agonist Alleviates Metabolic Syndrome. J Pharmacol Exp Ther. 2024. PMID: 37739806 https://pubmed.ncbi.nlm.nih.gov/37739806/
Okda HE, et al. Chemical optimization of the exercise mimetic SLU-PP-332 enables insight into estrogen-related receptor signaling. Int J Biol Macromol. 2026. PMID: 41850449 https://pubmed.ncbi.nlm.nih.gov/41850449/