SLU-PP-332 Adverse Events: What Studies Report

What the published record contains — and what it does not

SLU-PP-332 is a synthetic small molecule described as an agonist at the estrogen-related receptors (ERRα, ERRβ, ERRγ), a family of orphan nuclear receptors that sit downstream of the PGC-1 coactivators. It is not an approved medicine in any jurisdiction, and material circulating under that name is labelled for research use only. Among the peer-reviewed papers assembled for this page, none was a clinical trial of SLU-PP-332, none was a formal toxicology or tolerability study of the compound, and none reported adverse-event incidence, severity grading, discontinuation rates or dose-limiting findings for it. Where a reader asks what adverse events have been documented for SLU-PP-332 in people, the accurate answer from this citation set is that structured data of that kind were not found.

What the literature does contain is a body of work on the receptors the compound targets. Researchers reviewing the PGC-1/ERR axis characterised it as a central regulator of mitochondrial biogenesis, oxidative metabolism and cellular senescence across tissues (PMID 33112791). That receptor-level work is not a safety dataset for any particular ERR ligand, and the sections below are organised to make the distinction explicit: each describes what a study examined, in what model, and what it reported — not what SLU-PP-332 does in humans.

Why receptor biology is not a substitute for adverse-event data

Nuclear receptors are expressed in many tissues at once, and the same receptor can be engaged in opposite pharmacological directions. Researchers screening for selective ERRγ inverse agonists reported the identification of compounds that suppress, rather than activate, ERRγ transcriptional output (PMID 26771593), which illustrates that activation and inhibition at the same receptor are distinct pharmacologies with distinct expected consequences. Separately, a review of endocrine-disrupting chemicals reported that nuclear receptors are the major molecular targets of such compounds (PMID 31760044), a reminder that off-target or unintended nuclear-receptor engagement is a recognised toxicological theme in its own right.

Systems examined in the ERR literature

Cardiac and cardiovascular findings: What Studies Report

The heart is among the most mitochondria-dense tissues, which is why ERR and PGC-1 biology has been examined there repeatedly. One study reported that the epigenetic reader BRD4 governs the nucleus-encoded mitochondrial transcriptome and that this control is linked to cardiac function (PMID 33113340). A separate review examined how the renin-angiotensin system intersects with cardiac energy metabolism in heart failure (PMID 23886814). Neither paper administered SLU-PP-332, neither reported cardiac adverse events attributable to any ERR agonist, and neither provides a basis for predicting cardiovascular tolerability of the compound. They establish only that transcriptional control of mitochondrial gene programmes is a variable relevant to cardiac physiology.

Liver and metabolic findings: What Studies Report

Hepatic effects are a routine concern in any drug-safety assessment, and two papers in this set touch on liver biology through the same coactivator–receptor axis. Researchers studying the tire-rubber derivatives 6PPD and 6PPD-quinone reported that these chemicals induced lipid accumulation in hepatocytes through the ERRγ pathway (PMID 40412923). In a different model, the study of sodium fluoride–induced hepatotoxicity reported that melatonin-mediated upregulation of Sirt3 attenuated liver injury via MT1–PI3K/AKT–PGC-1α signalling (PMID 28912098). Both describe toxicant-driven scenarios in which ERR/PGC-1 signalling was implicated; neither tested an ERR agonist drug candidate, and neither reported liver enzyme changes, histology grading or hepatic adverse events for SLU-PP-332.

Kidney findings: What Studies Report

ERRα has been examined directly in renal disease models. A 2026 study reported that ESRRA–ATG5-mediated mitophagy enhanced arginine metabolism and alleviated features of diabetic kidney disease (PMID 41376268). That work framed ERRα activity as protective in a specific disease context; it did not report renal adverse events, nephrotoxicity signals, or dosing-related harm for any clinical ERR agonist, and its findings do not transfer to healthy kidneys or to a different compound.

Gastrointestinal findings: What Studies Report

Gastrointestinal complaints are among the most commonly reported adverse events for orally administered compounds in general, but no such reporting exists for SLU-PP-332 in this citation set. The closest relevant work reported that estrogen-related receptor alpha mitigated radiation-induced bowel injury through gut enrichment of Bacteroides vulgatus (PMID 40827662). The study examined ERRα in an injury-and-microbiome context rather than a tolerability context, and it did not document nausea, diarrhoea, or other symptomatic gastrointestinal endpoints associated with ERR-targeting drugs.

Bone and skeletal muscle findings: What Studies Report

Because ERR signalling has been proposed as a lever on tissue metabolism, bone and muscle have both been studied. A review discussed ERR receptors as potential targets in osteoporosis, examining their role in bone cell biology (PMID 20674386). In skeletal muscle, a review of natural products and PGC-1α in Duchenne muscular dystrophy described interest in the coactivator as a modulator of muscle oxidative capacity (PMID 32528825). Both are target-rationale papers. Neither reported musculoskeletal adverse events — such as myalgia, cramping, weakness or bone-density changes — following administration of an ERR agonist in humans.

Proliferation and oncology signals: What Studies Report

One recurring question around any nuclear-receptor agonist is whether increased receptor activity intersects with tumour biology. In this set, one paper reported that loss of RB1 triggered a dependence on ESRRG in retinoblastoma cells (PMID 35984874). The study framed ERRγ as a vulnerability to be exploited in a specific cancer genotype — that is, a target for inhibition — rather than reporting that ERR activation caused or accelerated malignancy. It is not evidence of carcinogenic risk for SLU-PP-332, and it is not evidence of its absence; the experiment simply did not address that question.

Endocrine and off-target considerations: What Studies Report

Researchers reviewing endocrine-disrupting chemicals reported that nuclear receptors are the principal targets through which such compounds exert effects (PMID 31760044). The ERRs are structurally related to the estrogen receptors but, as reflected in the receptor-screening literature, are pursued with distinct chemical tools, including selective ERRγ inverse agonists identified in a dedicated screening study (PMID 26771593). No paper in this set reported hormonal adverse events — such as changes in sex-steroid levels, menstrual disturbance or gynaecomastia — in association with SLU-PP-332.

Frequency, severity and population data: What Studies Report

Adverse-event pages are normally built from controlled trials, where investigators tabulate events by system organ class, grade them, and give the denominator. For SLU-PP-332, the citation set used here contains no such table and no such denominator: there were no Phase 1 safety data, no healthy-volunteer exposures, no long-term toxicology summaries and no post-marketing reports, because the compound has no approved product and no identified clinical programme among these sources. The nearest thing to systemic context is mechanistic review work on the PGC-1/ERR axis in ageing and mitochondrial function (PMID 33112791), which is not a safety document.

• Incidence rates: none reported in the cited literature for SLU-PP-332 (PMID 33112791).
• Severity grading: no graded adverse-event data identified (PMID 31760044).
• Populations studied: the cited work used cell, rodent and disease-model systems rather than human cohorts (PMID 41376268, PMID 40827662).
• Drug interactions: no interaction studies were identified in this citation set (PMID 26771593).

How this evidence is limited

Several limitations constrain any inference from the material above. First, receptor-pathway studies describe what a receptor does when manipulated genetically or by unrelated chemicals, not what a specific ligand does at a specific exposure; the mitophagy work in kidney disease, for example, manipulated ESRRA within a disease model rather than testing a drug candidate (PMID 41376268). Second, direction of modulation matters, and screening work has reported distinct chemical series acting as ERRγ inverse agonists (PMID 26771593). Third, species and model differences are substantial: rodent and cell-line findings on bowel injury and hepatocyte lipid handling were reported in experimental systems, not in people (PMID 40827662, PMID 40412923). Fourth, absence of reported adverse events in a mechanistic paper is not the same as an absence of risk, since those papers were not designed to detect harm (PMID 33112791).

A broader overview of SLU-PP-332 and the ERR pathway is maintained separately on PeptideU under the SLU-PP-332 learn entry, which covers mechanism and study landscape rather than adverse events.

This page is for educational purposes only and is not medical advice; consult a licensed physician about any health decision. It summarises published literature and does not characterise any compound as safe, effective or appropriate for use.

References

• ESRRA-ATG5-Mediated mitophagy enhances arginine metabolism to alleviate diabetic kidney disease (Autophagy, 2026)
• Estrogen-related receptor alpha mitigates radiation-induced bowel injury through gut enrichment of Bacteroides vulgatus (Gut Microbes, 2025)
• Aging, senescence and mitochondria: the PGC-1/ERR axis (Journal of Molecular Endocrinology, 2021)
• Nuclear receptors are the major targets of endocrine disrupting chemicals (Molecular and Cellular Endocrinology, 2020)
• Natural products, PGC-1α, and Duchenne muscular dystrophy (Acta Pharmaceutica Sinica B, 2020)
• ERR receptors as potential targets in osteoporosis (Trends in Endocrinology and Metabolism, 2010)
• RB1 loss triggers dependence on ESRRG in retinoblastoma (Science Advances, 2022)
• Tire rubber derivative 6PPD and 6PPD-Q induce lipid accumulation in hepatocytes through ERRγ pathway (Journal of Environmental Sciences, 2025)
• Impact of the renin-angiotensin system on cardiac energy metabolism in heart failure (Journal of Molecular and Cellular Cardiology, 2013)
• Epigenetic Reader BRD4 Governs Nucleus-Encoded Mitochondrial Transcriptome to Regulate Cardiac Function (Circulation, 2020)
• Identification of Selective ERRγ Inverse Agonists (Molecules, 2016)
• Melatonin-mediated upregulation of Sirt3 attenuates sodium fluoride-induced hepatotoxicity by activating the MT1-PI3K/AKT-PGC-1α signaling pathway (Free Radical Biology & Medicine, 2017)