SLU-PP-332: An ERR Agonist Exercise Mimetic for Metabolic Activation

This content is provided by Superpower Health for educational and informational purposes only. SLU-PP-332 is not FDA-approved and is not an investigational drug in clinical trials. It is a research tool compound studied exclusively in preclinical (mouse) models. It is not available through Superpower, by prescription, through compounding, or through any legitimate human-use channel. This page is not a substitute for medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider.

Every approved drug for improving metabolic health asks the same question differently: can we change what the body does with energy without relying entirely on diet and movement? GLP-1 agonists address appetite. Metformin targets hepatic glucose output. AMPK activators push cellular energy sensing. SLU-PP-332 approaches the problem from a different angle: it targets the transcription factors that exercise itself activates at the molecular level. The hypothesis is that mimicking those signals pharmacologically could replicate some of what endurance training does to muscle metabolism. That hypothesis has so far been tested only in mice. No human data exists. SLU-PP-332 is not available outside laboratory research settings.

Here is what SLU-PP-332 is, how its proposed mechanism works, what preclinical studies have found, and why the gap between those findings and any human application remains wide.

Key Takeaways

• Regulatory Status: Not FDA-approved. No Investigational New Drug (IND) application on file. No clinical trials in humans. Research tool compound only.
• Research Stage: Preclinical (mouse studies only); as of April 2026, no completed or registered human efficacy trials have been published.
• Availability: Not available for human use through any legitimate channel — no prescription pathway, no compounding pathway, no clinical trial enrollment. Gray-market material sold online is uncontrolled and carries unknown safety risks.
• Prescribing information: No FDA label exists. For compound reference data, see PubChem compound entry for SLU-PP-332.
• How it works: Activates estrogen-related receptors (ERRα, ERRβ, ERRγ) as a synthetic pan-agonist, inducing gene programs associated with aerobic exercise in mouse skeletal muscle.
• What preclinical research shows: In mouse models, SLU-PP-332 has been associated with enhanced treadmill endurance, reduced fat mass, improved insulin sensitivity, and changes in cardiac mitochondrial function. All findings are from animal studies. None have been replicated in humans.

SLU-PP-332 attracted significant media attention following a cluster of preclinical publications from Saint Louis University's Burris laboratory in 2023. That attention — and the "exercise in a pill" framing that accompanied it — has outpaced the scientific evidence substantially. Understanding what the research does and does not show is the starting point for any serious evaluation of this compound.

What SLU-PP-332 Is

SLU-PP-332 is a synthetic small molecule developed at Saint Louis University as a pharmacological tool for studying estrogen-related receptor (ERR) biology. It is not a peptide. It belongs to the medications collection because it is a small-molecule compound, not a peptide-based therapeutic. Searches for "slu pp 332 peptide" reflect a common misclassification; structurally and pharmacologically, it is a synthetic ligand for nuclear transcription factors.

The compound was first characterized by Billon, Sitaula, Banerjee, and colleagues from the Burris laboratory at Saint Louis University, published in ACS Chemical Biology in 2023, as a pan-agonist of ERRα, ERRβ, and ERRγ — the three members of the estrogen-related receptor subfamily. Unlike estrogen receptors (ERα, ERβ), estrogen-related receptors do not bind estrogen. They are constitutively active transcription factors that regulate mitochondrial biogenesis, oxidative phosphorylation, and fatty acid metabolism. SLU-PP-332 was designed as a research tool to activate all three ERR subtypes simultaneously and study what that activation produces in living systems.

How SLU-PP-332 Works: The ERR Pathway

Estrogen-related receptors and mitochondrial metabolism

Estrogen-related receptors are nuclear transcription factors that were identified in 1988 by Giguère and colleagues based on sequence homology to estrogen receptors. Despite their name, they are regulated by cellular energy status rather than by estrogen itself. As a 2015 review by Huss, Garbacz, and Xie in Biochimica et Biophysica Acta established, ERRs are constitutively active transcription factors that regulate genes central to oxidative phosphorylation, fatty acid oxidation, and mitochondrial biogenesis. A 2024 comprehensive review by Spinelli, Bruschi, Passalacqua, and colleagues in the International Journal of Molecular Sciences further characterized ERRα as a master regulator of glucose and lipid homeostasis across multiple tissues, identifying it as a target of interest for metabolic disease. The rationale for pharmacologically activating ERRs follows from this biology: if these receptors orchestrate the metabolic machinery that aerobic exercise upregulates, an agonist might recapitulate elements of that machinery without the exercise itself.

ERRα, ERRβ, and ERRγ: what each subtype contributes

ERRα is the most extensively studied of the three subtypes and has the strongest established link to skeletal muscle function. A 2023 study by Wattez, Eury, Hazen, and colleagues in Molecular Metabolism demonstrated that skeletal-muscle-specific combined ERRα/γ double knockout produced pale, oxidatively impaired muscles and severe exercise intolerance in mice — with dmKO animals unable to switch to lipid utilization during running — establishing that ERR activity is necessary for normal aerobic capacity. Independent work from the Evans laboratory confirmed the gain-of-function counterpart: a 2023 study by Xia, Scholtes, Dufour, and colleagues in Molecular Metabolism showed that genetic activation of ERRα in mouse skeletal muscle drove myofiber aerobic transformation — increased oxidative myofibers, angiogenesis, mitochondrial biogenesis, and fat oxidation — and enhanced running endurance and fatigue-resistance without exercise training. ERRγ contributes complementary roles in cardiac and oxidative fiber programming. A 2023 review by Sopariwala, Nguyen, and Narkar in the International Journal of Sports Medicine summarized estrogen-related receptor signaling across skeletal muscle fitness, noting that the ERR family collectively drives the transcriptional shift toward oxidative metabolism that characterizes trained muscle. A 2025 study by Fan, Oh, Wang, and colleagues published in PNAS provided direct mechanistic support, showing that ERRα, ERRβ, and ERRγ together regulate innate and adaptive mitochondrial energetics in mouse muscle in a manner that tracks with exercise-induced adaptation.

Why pan-agonism matters for the exercise mimetic hypothesis

SLU-PP-332 is designed as a pan-agonist — it activates all three ERR subtypes rather than targeting a single one. Earlier ERR tool compounds were subtype-selective; the medicinal chemistry program that produced SLU-PP-332 was aimed at generating a compound capable of activating the full ERR program simultaneously. A 2020 medicinal chemistry study by Shahien, Elagawany, Sitaula, and colleagues in Bioorganic Chemistry described the conversion of GSK4716 (an ERRβ/γ-selective agonist) to pan-ERR agonists, establishing the chemical rationale for the SLU-PP chemotype. The Burris laboratory's broader medicinal chemistry work, including a 2020 paper by Schoepke, Billon, Haynes, and colleagues in ACS Chemical Biology characterizing SLU-PP-1072 (a selective ERRα/γ inverse agonist from the same platform), demonstrates that this is an active tool-compound chemistry program — not a clinical development program. SLU-PP-332 was built to answer mechanistic questions in research settings, not to enter clinical development.

The connection to PGC-1α and established exercise biology

ERRs do not operate in isolation. They work in concert with PGC-1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha), the transcriptional coactivator considered the master regulator of mitochondrial biogenesis. A 2020 review by Islam, Hood, and Gurd in Applied Physiology, Nutrition, and Metabolism catalogued the regulators of exercise-induced skeletal muscle mitochondrial biogenesis beyond PGC-1α and identified ERRα as one of the key downstream effectors. ERRα is simultaneously a target of PGC-1α and an upstream regulator of PGC-1α's own transcriptional targets, forming a regulatory loop that amplifies the mitochondrial response to exercise. A 2023 review by Yoh, Ikeda, Horie, and Inoue in the International Journal of Molecular Sciences elaborated on how estrogen, estrogen receptors, and ERRs interact in skeletal muscle mitochondrial function. This biological context is what gives the exercise mimetic hypothesis its theoretical basis — and also what makes it difficult to validate pharmacologically, since the endogenous system depends on coordinated signals that a single agonist may incompletely replicate.

What Preclinical Research Has Found

All efficacy data for SLU-PP-332 comes from mouse studies. None of the findings described below have been replicated in humans. Individual results in humans, if any studies were ever conducted, could differ substantially. These findings describe what was observed in specific animal models under specific experimental conditions.

Endurance and skeletal muscle gene expression

The foundational characterization of SLU-PP-332's in vivo effects appeared in the 2023 ACS Chemical Biology paper by Billon, Sitaula, Banerjee, and colleagues from the Burris laboratory. In this preclinical study, mice (n = 6 per group) received SLU-PP-332 at 50 mg/kg intraperitoneally — either as a single acute dose 1 hour before treadmill testing or as chronic twice-daily dosing over 10 days — compared against vehicle (DMSO) controls. Treated mice showed enhanced treadmill running distance and running time relative to vehicle controls, alongside induction of an ERRα-dependent acute aerobic exercise gene program in skeletal muscle (including Ddit4 and Slc25a25 upregulation) — a transcriptional signature resembling what is observed after endurance exercise. The gene program activated included targets associated with fatty acid oxidation, mitochondrial electron transport chain components, and oxidative fiber specification. Numerical effect sizes for running distance and p-values were reported only graphically in the published figures, and the very small cohort (n = 6/group) limits precision. This paper is the primary citation underlying the exercise mimetic framing that spread through media coverage. It is a mechanistic and pharmacological characterization paper in an animal model — not a clinical or translational study.

Metabolic syndrome and body composition

A 2024 follow-up paper by Billon, Schoepke, Avdagic, and colleagues published in the Journal of Pharmacology and Experimental Therapeutics examined SLU-PP-332 across three mouse models: C57Bl6 mice on normal chow (n = 8/group), diet-induced obese mice on high-fat diet (n = 7/group), and leptin-deficient ob/ob mice (n = 8/group), with treatment durations of 15–28 days depending on model. Compared against vehicle controls, DIO mice treated with SLU-PP-332 showed decreased fat mass accumulation with reductions in adipocyte size, ob/ob mice showed fat mass reduction over 15 days, and treated animals demonstrated increased energy expenditure, increased fatty acid oxidation, and improved insulin sensitivity in metabolic syndrome models (p-values <0.05 to <0.0001 for key comparisons per the published figures); glucose metabolism was not improved in normal chow-fed mice. These findings provided the basis for claims about SLU-PP-332's potential relevance to fat oxidation and weight-related outcomes. They are mouse findings in a controlled experimental model, and do not predict human efficacy or tolerability.

Cardiac function in heart failure models

A 2024 paper by Xu, Billon, Li, and colleagues published in Circulation examined pan-ERR agonists (including SLU-PP-332 and its successor compound SLU-PP-915) in the mouse transverse aortic constriction model of pressure-overload heart failure. In 8-week-old mice post-27-gauge TAC surgery, SLU-PP-332 at 25 mg/kg intraperitoneally twice daily (treatment period extending up to 6 weeks; n = 4–23 per measurement) significantly improved ejection fraction, ameliorated cardiac fibrosis (p < 0.05 vs sham-vehicle), increased survival, and enhanced cardiac fatty acid metabolism and mitochondrial oxidative capacity compared to vehicle-treated TAC controls, while producing no effect on cardiac hypertrophy. This study extended the preclinical rationale for ERR agonism beyond skeletal muscle into cardiac biology. It also signals that a compound in this class would require cardiac safety evaluation as a priority in any future clinical development — a step that has not been initiated for SLU-PP-332.

Kidney and anti-inflammatory effects

A 2023 paper by Wang, Myakala, Libby, and colleagues in the American Journal of Pathology reported that ERR agonism with SLU-PP-332 reversed mitochondrial dysfunction and reduced inflammation in an aging kidney mouse model. This finding extends the preclinical mechanism of ERR activation into a third tissue — kidney — beyond the skeletal muscle and cardiac findings described above. A 2025 review by Bonanni, Falvino, Matticari, and colleagues published in Frontiers in Physiology positioned ERR-targeting approaches as a potential strategy to counteract age-related muscle atrophy from physical inactivity, further expanding the proposed therapeutic space. A 2025 paper by Nguyen, Huang, Poliakova, and colleagues in the FASEB Journal reported that ERRα promotes skeletal muscle regeneration and may mitigate Duchenne muscular dystrophy pathology in mouse models.

The oral bioavailability problem

SLU-PP-332 has poor oral bioavailability, a significant pharmacokinetic limitation for any compound intended for human use. This limitation prompted the Burris laboratory to develop SLU-PP-915, a successor compound with improved oral activity. A 2023 medicinal chemistry paper by Hampton, Sitaula, Billon, and colleagues in the European Journal of Medicinal Chemistry described the synthesis and pharmacological optimization of the SLU-PP chemical series leading to SLU-PP-915. A 2026 in vivo study by Billon, Appourchaux, Côté, and colleagues in the Journal of Pharmacology and Experimental Therapeutics confirmed that SLU-PP-915 is orally active and improves aerobic exercise capacity in mice. The development of SLU-PP-915 as a more pharmacokinetically suitable successor is itself evidence that SLU-PP-332 was always a research tool rather than a clinical candidate.

The "Exercise in a Pill" Problem

SLU-PP-332's 2023 media coverage relied heavily on the framing that activating exercise-related gene programs pharmacologically could substitute for, or replicate, the benefits of physical activity. This framing is scientifically misleading in important ways.

Exercise produces systemic effects across cardiovascular, metabolic, neurological, musculoskeletal, and immune systems simultaneously. These effects emerge from the coordinated response of hundreds of molecular pathways, mechanical loading on bones and joints, hemodynamic changes, and adaptations that accumulate over time. A single transcription factor agonist activating one branch of the exercise response cannot reproduce this complexity. The fundamental limitation of exercise mimetics was articulated in a 2017 perspective by Li and Laher in Clinical Pharmacology and Therapeutics titled "Exercise Mimetics: Running Without a Road Map," which explicitly cautioned that the therapeutic potential of exercise mimetics rests on preclinical rodent findings and that translation to humans involves substantial unknowns. That caution was written before SLU-PP-332 existed and applies with full force to it.

The comparison to other exercise mimetic compounds is instructive. AMPK activators such as AICAR and metformin have been studied extensively as metabolic modulators. A 2022 review by Spaulding and Yan in the Annual Review of Physiology addressed AMPK and its role in exercise adaptation, and a 2021 study by Ericsson, Steneberg, Nyrén, and colleagues in Communications Biology examined the AMPK activator O304 in aged mice with improvements in metabolic and exercise capacity. Neither class of compound has demonstrated the breadth of exercise's clinical benefits in human trials, despite decades of development. A 2024 review by Zhao in the Journal of Neuroinflammation surveyed exercise mimetics broadly as a strategy for neuroinflammation and Alzheimer's disease, noting the field's promise alongside its consistent failure to translate preclinical findings into approved therapeutics. SLU-PP-332 exists within this history, not apart from it.

A pre-SLU-PP-332 review by Tripathi, Yen, and Singh, published in the International Journal of Molecular Sciences in 2020, characterized ERRα as an underappreciated target for metabolic diseases and outlined the therapeutic rationale for ERR agonism. That review established the scientific hypothesis. The gap between a credible hypothesis and a validated human therapeutic is where SLU-PP-332 currently sits — and, given its pharmacokinetic limitations, it may never cross that gap. Its successor compound SLU-PP-915 is closer on paper, but also has no human data as of April 2026.

Regulatory Status and Anti-Doping Classification

As of April 2026, SLU-PP-332 has no FDA approval, no IND application, and no registered clinical trials in humans. It is not available by prescription, through compounding pharmacies, or through any legitimate therapeutic channel. It is classified as a research tool compound, available only to licensed research institutions for use in preclinical studies.

For athletes, there is a separate regulatory consideration. The compound has begun appearing in anti-doping surveillance. An in vitro metabolism and doping-control analysis by Avliyakulov, Sobolevsky, Ahrens, and colleagues published in Drug Testing and Analysis in 2026 characterized the metabolic profile of SLU-PP-332 and identified detection methods for doping control purposes. A companion paper by Möller, Krug, and Thevis published in Rapid Communications in Mass Spectrometry in 2026 independently characterized in vitro metabolism of both SLU-PP-332 and SLU-PP-915 and noted the doping potential of this compound class. The 16th-edition annual banned-substance review by Thevis, Kuuranne, and Geyer, published in Drug Testing and Analysis in 2024, surveyed analytical approaches in human sports drug testing across 2022–2023 and catalogued emerging metabolic modulators — including ERR-pathway agents — as substances warranting heightened anti-doping surveillance.

The anti-doping metabolite papers are significant beyond their sport context. They signal that regulatory and anti-doping bodies treat SLU-PP-332 as a substance of concern for misuse — not as a therapeutic compound approaching clinical development. The existence of gray-market material sold online under this name reflects interest generated by media coverage rather than any legitimate therapeutic pathway. Compounds sold as "SLU-PP-332" through unregulated channels are uncontrolled in purity, identity, and dose. No safety data in humans exists to contextualize any exposure.

Who Is Not a Candidate for SLU-PP-332

SLU-PP-332 has no indication, no approved use, and no clinical trial population. The concept of candidacy does not apply to a research tool compound. The following are relevant considerations for anyone seeking to understand the current state of this compound:

• No human has been studied with SLU-PP-332 in a controlled clinical setting. No safety data in humans has been published.
• SLU-PP-332 has poor oral bioavailability, which means its pharmacokinetics in humans are entirely unknown from any empirical data.
• ERR agonism affects cardiac metabolism in addition to skeletal muscle. Any human exposure would occur without cardiovascular safety monitoring of any kind.
• Gray-market compounds sold as SLU-PP-332 carry no verified identity, purity, or dose. These are not the same as research-grade material used in published studies.
• The compound is not excluded from anti-doping testing and may be detectable under current surveillance methods.
• No legitimate prescribing physician can prescribe this compound. Any source offering it as a prescription or compounded product is operating outside any legal therapeutic framework.

These are not cautionary generalizations. They reflect the actual regulatory and scientific status of this compound as of April 2026.

Understanding Your Metabolic Baseline

The biological targets that SLU-PP-332 is proposed to affect — mitochondrial function, fatty acid oxidation, insulin sensitivity, and body composition — are measurable through standard blood panels. Whether or not a compound in this class ever completes clinical development, understanding your metabolic markers provides an objective foundation for evaluating your health and discussing options with a provider. The relevant biomarkers include fasting glucose and HbA1c, which reflect glucose regulation and long-term glycemic status; fasting insulin, which provides the most sensitive available signal of insulin resistance before glucose dysregulation becomes apparent; a full lipid panel including triglycerides and HDL cholesterol, which track the lipid-handling changes that aerobic conditioning is known to produce; and liver enzymes including ALT, which reflect hepatic metabolic activity relevant to fat oxidation. The metabolic health and weight loss biomarker guide provides additional context on interpreting these values together.

That approach — understanding your biology through objective measurement, then making decisions grounded in that data — is central to Superpower's approach to preventive health. The compounds under investigation will change. The value of knowing your metabolic baseline will not.

IMPORTANT SAFETY INFORMATION

SLU-PP-332 is not FDA-approved for any indication. No IND application has been filed. No clinical trials in humans have been registered or conducted as of April 2026. Superpower Health does not prescribe, sell, compound, or facilitate access to SLU-PP-332. This article is provided for educational and informational purposes only and does not constitute medical advice, a recommendation for use, or an endorsement of this compound.

No human safety data exists for SLU-PP-332. All pharmacological and efficacy data are derived from mouse studies. The compound cannot be presumed safe or tolerable in humans based on animal findings. Adverse effects in humans are unknown.

SLU-PP-332 has poor oral bioavailability. Its pharmacokinetics in humans have not been studied. Gray-market material sold as SLU-PP-332 is uncontrolled in purity, identity, and dosage. Purchase or use of such material carries unknown risks and no legitimate therapeutic basis.

ERR agonism affects cardiac metabolism in preclinical models. The cardiac safety profile of SLU-PP-332 in humans has not been evaluated. Any human exposure to this compound would occur without established cardiovascular safety data.

Anti-doping: As of April 2026, SLU-PP-332 is under active anti-doping surveillance following in vitro metabolism characterization studies published in 2026. Athletes subject to anti-doping regulations should treat this compound as carrying detection risk.

Do not use SLU-PP-332 as a substitute for medical treatment, exercise, or approved therapies for any metabolic, cardiovascular, or musculoskeletal condition. Always consult a qualified healthcare provider before making changes to your health routine.

Additional Questions

How does SLU-PP-332 compare to semaglutide or tirzepatide?

They operate through entirely different mechanisms. Semaglutide and tirzepatide are GLP-1 receptor agonists (with tirzepatide also activating GIP) that are FDA-approved and have extensive human clinical trial data. SLU-PP-332 targets nuclear transcription factors (ERRs) and has only preclinical mouse data. The comparison is not clinically meaningful because one class has established human efficacy and safety data and the other has none.

Is SLU-PP-332 the same as a peptide?

No. SLU-PP-332 is a small-molecule synthetic compound, not a peptide. It is frequently misclassified in online searches as a peptide ("slu pp 332 peptide"), but it is structurally distinct from peptide compounds. It is a ligand for nuclear receptors, not a peptide sequence acting through peptide receptors.

Is SLU-PP-332 banned in sport?

As of April 2026, SLU-PP-332 is under active anti-doping surveillance. In vitro metabolism studies published in 2026 have characterized its detection profile for doping control purposes, and anti-doping authorities have identified metabolic modulators in this class as substances of concern. Athletes subject to anti-doping rules should treat it as a compound that may be detected and carries significant regulatory risk regardless of its lack of approval.

When will SLU-PP-332 be available?

No timeline for human availability can be projected. SLU-PP-332 itself has not entered clinical development. Its successor SLU-PP-915 is at the preclinical stage as of April 2026. Even for compounds that do enter clinical trials, Phase 1 through Phase 3 development typically takes a decade or more, and there is no guarantee that any compound in this class will receive regulatory approval. The exercise mimetic field has a long history of promising preclinical results that did not translate to human therapeutics.

What biomarkers should I test if I am interested in metabolic health?

The metabolic markers most relevant to what SLU-PP-332's proposed mechanism targets include fasting glucose, HbA1c, fasting insulin, a lipid panel (triglycerides, HDL, LDL), and liver enzymes. These markers collectively describe glucose regulation, insulin sensitivity, lipid handling, and hepatic metabolic function — the same dimensions that aerobic exercise and mitochondrial activation affect. Establishing a baseline of these values provides objective context for evaluating metabolic health and discussing options with a qualified provider.