SLU-PP-332 Peptide: The Exercise Mimetic Reshaping Metabolic Research in 2025
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SLU-PP-332 is a synthetic, non-steroidal small molecule developed at Washington University School of Medicine and St. Louis College of Pharmacy that acts as a pan-agonist of estrogen-related receptors (ERRα, ERRβ, and ERRγ). Often called an “exercise mimetic” or “exercise in a pill,” it starts the same genetic programs triggered by aerobic exercise—increasing energy-cell biogenesis, oxidant muscle fiber formation, and fatty acid oxidation.
In lab mouse studies, SLU-PP-332 boosted treadmill running endurance by about 70% and reduced body fat by 12% without changes in diet or physical activity (Billon et al., ACS Chem. Biol., 2023; Billon et al., J. Pharmacol. Exp. Ther., 2024).
What Is SLU-PP-332?
SLU-PP-332 is a synthetic, non-steroidal small molecule that belongs to the emerging class of compounds known as exercise mimetics—substances designed to replicate the cellular and body effects of physical exercise without needing actual physical activity. Developed by a research team led by Dr. Thomas P. Burris at the Center for Clinical Pharmacology at Washington University School of Medicine and St.
Louis College of Pharmacy, the compound was first described in a landmark 2023 paper published in ACS Chemical Biology that has since been cited more than 36 times across top-tier journals including Nature, Circulation, and Pharmacological Reviews (Billon et al., 2023).
The name “SLU-PP-332” itself provides a clue to its origins. “SLU” stands for Saint Louis University, where the early precursor work was conducted before the research group moved to Washington University. The “PP” designation references the laboratory naming convention, and “332” identifies the specific compound within the chemical series. Dr.
Burris has since relocated to the University of Florida Genetics Institute, where growth of next-generation ERR agonists continues.
SLU-PP-332 Is Not Actually a Peptide
Despite its widespread marketing as a “peptide” across research chemical suppliers and online forums, SLU-PP-332 is technically not a peptide. Peptides are defined as short chains of amino acids linked by peptide bonds—compounds like BPC-157, TB-500, and KPV fall into this category. SLU-PP-332, by contrast, is a small organic molecule with a distinct chemical scaffold that does not contain amino acid sequences.
It is classified as a small molecule ligand that binds to nuclear receptors, placing it in a pharmacological category more comparable to pharmaceutical drugs like tamoxifen or rosiglitazone than to research peptides. The term “SLU-PP-332 peptide” persists largely because research chemical suppliers categorize it alongside peptides for commercial convenience, and the broader research community has adopted the terminology colloquially.
Chemical Profile and Classification
From a pharmacological standpoint, SLU-PP-332 is classified as a pan-agonist of the estrogen-related receptor family. It targets all three ERR subtypes—ERRα, ERRβ, and ERRγ—but shows the highest binding potency for ERRα. The compound has enough pharmacokinetic properties for in vivo use, meaning it can be gave to living organisms and reach its target tissues at effective levels.
In published mouse studies, it was gave via intraperitoneal injection at 25 mg/kg twice daily and showed measurable natural activity within two hours of the first dose, as evidenced by an immediate shift in respiratory exchange ratio toward fat oxidation (Billon et al., 2024).
SLU-PP-332 is a synthetic small molecule, not a peptide, that starts estrogen-related receptors to mimic the body effects of aerobic exercise. It was developed at Washington University School of Medicine and remains in the lab study stage with no human clinical trials completed.
How Does SLU-PP-332 Work? The ERR Agonist Mechanism of Action
Grasp how SLU-PP-332 produces its exercise-mimicking effects needs a deeper look at the estrogen-related receptors it targets and the downstream natural cascades those receptors control. The mechanism is elegant, multi-layered, and fundamentally different from how stimulants, fat burners, or anabolic compounds work.
What Are Estrogen-Related Receptors (ERRs)?
Estrogen-related receptors are a family of three orphan nuclear receptors—ERRα, ERRβ, and ERRγ—that were originally identified because of their structural similarity to estrogen receptors. However, despite the possibly confusing name, ERRs do not bind estrogen and have no direct role in estrogen signaling or fertility biology. They are called “orphan” receptors because, until recently, no natural ligand (binding molecule) had been definitively identified for them.
Instead, they are constitutively active transcription factors that regulate the expression of genes involved in cellular energy body function.
Each ERR subtype plays a distinct but overlapping role in energy homeostasis. ERRα is the most extensively studied and is highly expressed in metabolically demanding tissues including skeletal muscle, heart, kidney, and brown adipose tissue. It serves as a master regulator of energy-cell biogenesis, fatty acid oxidation, and oxidant phosphorylation—mainly controlling the genetic programs that find how efficiently your cells produce energy from nutrients.
ERRβ is less well characterized but plays important roles in placental growth and inner-ear function. ERRγ is highly expressed in the heart and brain and shares large functional redundancy with ERRα in regulating cardiac body function and muscle contraction (Burris et al., Pharmacol. Rev., 2023).
The Three-Stage Activation Cascade
When SLU-PP-332 enters a cell and binds to ERRα, it triggers a precise sequence of cell-level events that can be understood as a three-stage start cascade. In the first stage, receptor start, SLU-PP-332 binds to the ligand-binding domain of ERRα, inducing a conformational change that enhances the receptor’s power to recruit transcriptional coactivators, very PGC-1α (peroxisome proliferator-started receptor gamma coactivator 1-alpha).
PGC-1α is often described as the “master regulator” of energy-cell biogenesis, and its recruitment is the key event that bridges receptor start to body reprogramming.
The second stage involves transcriptional reprogramming. The ERRα-PGC-1α complex binds to estrogen-related receptor response elements (ERREs) in the promoter regions of hundreds of target genes. RNA sequencing studies from the Circulation heart failure paper identified over 1,100 differentially expressed genes in response to ERR agonist treatment, with upregulated genes enriched in fatty acid body function, oxidant phosphorylation, and cardiac muscle contraction pathways (Xu et al., 2024).
Simultaneously, cell cycle and developmental genes were downregulated, suggesting that ERR start redirects cellular resources away from growth and proliferation toward body efficiency.
The third stage produces the functional body output. New mitochondria are assembled within muscle fibers (energy-cell biogenesis), existing mitochondria become more efficient at burning fatty acids (enhanced β-oxidation), and muscle cells shift from glycolytic (fast-twitch, sugar-burning) fibers toward oxidant (slow-twitch, fat-burning) fibers. The net result is a cell that looks and behaves as though it has been subjected to weeks of endurance training—despite getting a chemical signal rather than a mechanical one.
RNA sequencing from neonatal rat ventricular myocytes treated with SLU-PP-332 identified 411 upregulated and 726 downregulated genes. Of the 40 often upregulated body genes, 22 (55%) were mainly involved in fatty acid or lipid body function, including key rate-limiting enzymes like CPT1b, ACADM, and PDK4 (Xu et al., Circulation, 2024).
ERRα vs. ERRγ: Which Receptor Matters More?
An important nuance in SLU-PP-332 pharmacology is the differential contribution of ERR subtypes to different natural outcomes. The 2023 exercise capacity study showed that ERRα start was key for the exercise endurance phenotype—when ERRα signaling was blocked, the endurance-enhancing effects of SLU-PP-332 were abolished (Billon et al., 2023). However, the 2024 heart failure study from Circulation found that ERRγ was the main mediator of cardioprotective effects, using both in vitro and in vivo genetic dependency experiments to show this specificity (Xu et al., 2024).
This tissue-specific receptor dependency is an important consideration for grasp why SLU-PP-332 may produce different benefit profiles in skeletal muscle versus cardiac tissue, and it informs the ongoing growth of more selective ERR agonists.
Why Is SLU-PP-332 Called an “Exercise in a Pill”?
The phrase “exercise in a pill” has captured public imagination ever since Nature featured SLU-PP-332 in a 2024 article titled “Why is exercise good for you? Scientists are finding answers in our cells” (Conroy, 2024). But the label is both illuminating and misleading, and grasp why needs examining what exercise actually does at the cell-level level and how closely SLU-PP-332 replicates those effects.
What Exercise Does to Your Cells
When you engage in sustained aerobic exercise—running, cycling, swimming—your skeletal muscle cells experience a cascade of body stresses that trigger adaptive responses. ATP is rapidly consumed, AMP levels rise, calcium floods the cytoplasm, and reactive oxygen species increase transiently. These signals converge on master control proteins including AMPK, CaMKII, and finally PGC-1α, which then drive the transcription of genes responsible for building new mitochondria, increasing capillary density, converting fast-twitch muscle fibers to fatigue-resistant slow-twitch fibers, and upregulating the enzymatic machinery for fatty acid oxidation.
Over weeks and months of repeated exercise bouts, these adaptations build up into what we recognize as improved heart fitness and endurance capacity.
How SLU-PP-332 Shortcuts the Process
SLU-PP-332 mainly enters this cascade at the level of transcriptional control, bypassing the upstream mechanical and body stress signals entirely. By directly starting ERRα and recruiting PGC-1α, it instructs muscle cells to execute the same genetic program that exercise would trigger—but without needing a single step on a treadmill. The 2023 ACS Chemical Biology study showed this convincingly.
Mice treated with SLU-PP-332 showed a major increase in type IIa oxidant muscle fibers and, critically, an ERRα-dependent acute aerobic exercise genetic program was induced even without physical activity. On treadmill tests, treated mice ran about 70% farther than untreated controls, a magnitude of endurance gain that would often need weeks of progressive training in untreated animals (Billon et al., 2023).
What SLU-PP-332 Cannot Replace
However, calling SLU-PP-332 a complete “exercise replacement” overstates what the compound does. Physical exercise produces benefits that extend far beyond body adaptation in skeletal muscle. Exercise strengthens bones through mechanical loading, improves joint mobility, enhances neuromuscular coordination, releases brain-derived neurotrophic factor (BDNF) for cognitive benefits, tunes immune function, and produces profound psychological effects through endorphin release and social interaction.
SLU-PP-332 addresses only the body and energy-cell components of this vast benefit spectrum. For patient populations who genuinely cannot exercise—the elderly with mobility limitations, people recovering from surgery, patients with severe heart failure or neuromuscular diseases—even this partial replication of exercise benefits could be transformative. The compound is best understood as a body exercise mimetic rather than a total exercise substitute.
SLU-PP-332 replicates the body and energy-cell adaptations of aerobic exercise by directly starting ERR-dependent gene programs. However, it cannot reproduce the mechanical, neurological, psychological, or immune benefits of physical activity. Its greatest treatment possible lies in serving patient populations with severely limited exercise capacity.
SLU-PP-332 Benefits: What Preclinical Research Actually Shows
The published lab evidence for SLU-PP-332 spans three major peer-reviewed studies conducted between 2023 and 2024, each examining different facets of the compound’s natural activity. It is essential to emphasize that all findings come from mouse models and in vitro cell studies—no human clinical trial data exists for SLU-PP-332 as of 2025.
The following benefit categories represent what has been showed in controlled lab research environments.
Benefit 1: Enhanced Exercise Endurance
The most striking and widely reported finding is the dramatic gain in exercise capacity saw in the 2023 study. Mice gave SLU-PP-332 ran about 70% farther on treadmill endurance tests compared to vehicle-treated controls. This gain was accompanied by measurable changes in muscle fiber makeup, with treated animals showing greatly increased type IIa oxidant fibers—the same slow-twitch, fatigue-resistant fibers that elite endurance athletes develop through years of training.
Mechanistically, the study confirmed that this endurance boost was ERRα-dependent, as the effect was abolished when ERRα signaling was genetically disrupted (Billon et al., ACS Chem. Biol., 2023).
Benefit 2: Fat Loss Without Diet or Exercise Changes
The 2024 body syndrome study provided compelling evidence for SLU-PP-332’s fat-reducing effects. In diet-induced obese (DIO) mice—animals fed a high-fat diet to simulate human obesity—28 days of SLU-PP-332 treatment produced about 12% body weight reduction. Crucially, this weight loss came entirely from decreased fat mass with no reduction in lean body mass and no changes in food intake or locomotor activity.
The compound mainly reprogrammed fuel use without suppressing appetite or increasing physical movement. Respiratory exchange ratio (RER) measurements showed that this body shift toward fat oxidation occurred within just two hours of the very first dose, showing notably rapid onset of action. In genetically obese ob/ob mice, the compound also decreased overall adiposity, reduced liver weight, and attenuated hepatic steatosis (fatty liver disease) (Billon et al., J. Pharmacol.>
Exp. Ther., 2024).
Benefit 3: Improved Glucose Tolerance and Metabolic Flexibility
Beyond fat loss, SLU-PP-332 improved glucose tolerance in diet-induced obese mice, addressing one of the core pathological features of body syndrome and type 2 diabetes. By upregulating PDK4 (pyruvate dehydrogenase kinase 4)—a key enzyme that shifts substrate use from glucose to fatty acids—the compound enhanced body flexibility, letting cells to toggle more efficiently between fuel sources depending on natural demands.
This dual action on both fat body function and glucose handling positions SLU-PP-332 as a possible tool for addressing the multi-factorial nature of body syndrome, where insulin resistance, dyslipidemia, and excess adiposity occur simultaneously (Billon et al., 2024).
Benefit 4: Cardioprotection in Heart Failure Models
Perhaps the most clinically major finding comes from the 2024 Circulation study, which showed that both SLU-PP-332 and its structurally distinct successor SLU-PP-915 provided large cardioprotection in a pressure-overload model of heart failure. Treated mice showed greatly improved ejection fraction (a measure of how well the heart pumps blood), ameliorated cardiac fibrosis, and increased survival rates compared to vehicle-treated controls.
Metabolomics test revealed large normalization of fatty acid, lipid, and TCA/oxidant phosphorylation metabolites in the failing heart. Electron microscopy showed that energy-cell ultrastructure—severely fragmented and damaged in untreated heart failure hearts—was preserved in ERR agonist-treated animals. Notably, these cardioprotective effects occurred without affecting cardiac hypertrophy, suggesting that ERR agonism prevents the transition from compensatory hypertrophy to decompensated heart failure rather than preventing hypertrophy itself (Xu et al., Circulation, 2024).
Benefit 5: Mitochondrial Biogenesis and Muscle Fiber Conversion
Running through all of SLU-PP-332’s documented benefits is its basic effect on energy-cell biology. The compound drives the creation of new mitochondria (biogenesis) and improves the oxidant capacity of existing ones. In isolated adult mouse cardiomyocytes, SLU-PP-332 treatment greatly elevated maximal respiratory capacity and increased palmitate-induced oxygen consumption, directly showing enhanced fatty acid oxidation at the cellular level.
In skeletal muscle, the conversion of glycolytic fibers to oxidant fibers represents a structural remodeling that underlies the endurance gains (Billon et al., 2023; Xu et al., 2024).
| Benefit Category | Key Finding | Study | Model |
|---|---|---|---|
| Exercise endurance | ~70% increase in treadmill running distance | Billon et al., 2023 | Mice (C57BL/6J) |
| Fat loss | ~12% body weight reduction (fat mass only) | Billon et al., 2024 | DIO mice |
| Metabolic shift | RER shift to fat oxidation within 2 hours | Billon et al., 2024 | DIO mice |
| Glucose tolerance | Improved GTT in obese mice | Billon et al., 2024 | DIO mice |
| Fatty liver | Reduced hepatic steatosis and liver weight | Billon et al., 2024 | ob/ob mice |
| Heart failure | Improved ejection fraction + survival | Xu et al., 2024 | TAC mice |
| Cardiac fibrosis | Significant reduction in fibrotic area | Xu et al., 2024 | TAC mice |
| Mitochondrial function | Preserved ultrastructure + increased OCR | Xu et al., 2024 | Mouse cardiomyocytes |
| Muscle fiber conversion | Increased type IIa oxidative fibers | Billon et al., 2023 | Mice (C57BL/6J) |
Every benefit listed above comes exclusively from animal models and cell studies. No human clinical trials have been conducted for SLU-PP-332. Lab results in mice often fail to translate to humans at the same magnitude or with the same safety profile. These findings should be interpreted as scientific hypotheses needing human validation, not as set up treatment outcomes.
SLU-PP-332 vs. Other Exercise Mimetics: How Do They Compare?
SLU-PP-332 exists within a growing class of compounds collectively described as exercise mimetics, each targeting different cell-level pathways to replicate specific aspects of exercise physiology. Grasp how these compounds differ in mechanism, effect, and safety profile is essential for researchers designing studies in this space and for consumers trying to make sense of the often-confusing marketplace of body modulators.
| Compound | Primary Target | Key Mechanism | Key Preclinical Finding | Human Trials? | WADA Status |
|---|---|---|---|---|---|
| SLU-PP-332 | ERRα/β/γ | Mitochondrial biogenesis, oxidative fiber conversion, FA oxidation | 70% endurance increase; 12% fat loss in DIO mice | No | Prohibited (S4) |
| Cardarine (GW501516) | PPARδ | Fatty acid oxidation, endurance gene activation | Improved endurance and lipid profiles in mice | Halted (Phase II) | Prohibited (S4) |
| SR9009 (Stenabolic) | Rev-Erbα/β | Circadian rhythm modulation, metabolic regulation | Reduced fat mass and cholesterol in mice | No | Prohibited (S4) |
| AICAR | AMPK | Direct AMPK activation mimicking energy depletion | Improved endurance without training in sedentary mice | Limited (other indications) | Prohibited (S4) |
| SLU-PP-915 | ERRα/β/γ | Same as SLU-PP-332 with improved potency and oral bioavailability | Stronger cardioprotection than SLU-PP-332 in HF model | No | Prohibited (S4) |
SLU-PP-332 vs. Cardarine (GW501516)
Cardarine and SLU-PP-332 are perhaps the two most often compared exercise mimetics. Cardarine starts PPARδ (peroxisome proliferator-started receptor delta), a nuclear receptor that regulates fatty acid catabolism and energy output in muscle. Both compounds increase endurance and promote fat oxidation, and both are banned by WADA under the same S4 category.
However, there is one key difference that separates them. Cardarine’s clinical growth was permanently abandoned by GlaxoSmithKline in 2007 after lab studies in rats revealed an increased incidence of tumors across multiple organ systems during long-term, high-dose exposure. While the relevance of these findings to human physiology at lower doses remains debated, the carcinogenicity signal was considered sufficiently concerning to halt all human growth.
SLU-PP-332, by contrast, has not shown similar carcinogenicity signals in any published lab study, though it must be noted that long-term carcinogenicity studies mainly designed to assess this endpoint have not been published for SLU-PP-332 either.
SLU-PP-332 vs. SR9009 (Stenabolic)
SR9009 targets Rev-Erbα and Rev-Erbβ, nuclear receptors that tune circadian rhythm and downstream body processes. While SR9009 showed impressive fat loss and body effects in early mouse studies, later research revealed critically poor oral uptake—when gave orally, very little of the compound reaches systemic circulation. This pharmacokinetic limitation has raised questions about whether the body effects saw in studies using intraperitoneal injection would translate to practical oral dosing scenarios.
SLU-PP-332 faces similar uptake constraints when gave orally in its current form, though the next-generation compound SLU-PP-915 was mainly designed to address this limitation (Billon et al., J. Pharmacol. Exp. Ther., 2026).
SLU-PP-332 vs. SLU-PP-915: The Next Generation
SLU-PP-915 is a second-generation pan-ERR agonist developed by the same research group. It is structurally distinct from SLU-PP-332—built on a thiophene scaffold rather than SLU-PP-332’s original chemical framework—and was designed using a structure-based approach leveraging the crystal structure of ERRγ with the known agonist GSK-4716. SLU-PP-915 shows more balanced activity between ERRα and ERRγ (EC50 about 450 nM for both) and, importantly, showed oral uptake in lab models.
In the heart failure study, SLU-PP-915 showed even stronger cardioprotective effects than SLU-PP-332, greatly improving ejection fraction, stroke volume, and cardiac output. The growth of a structurally distinct second compound that produces the same treatment effects was considered very important because it provided definitive evidence that the saw benefits were truly ERR-mediated (on-target) rather than artifacts of a single compound’s off-target effects (Hampton et al., 2023; Xu et al., 2024).
SLU-PP-332 Dosage: What Preclinical Studies Used
Setting up a definitive “recommended dosage” for SLU-PP-332 is not possible because no human clinical trials have been conducted and no control body has approved any dose for human use. What follows is a summary of the dosing protocols used in published lab research, along with a candid discussion of the anecdotal community practices that have emerged despite the absence of human safety data.
Published Preclinical Dosing Protocols
| Study | Dose | Route | Frequency | Duration | Vehicle |
|---|---|---|---|---|---|
| Billon et al., 2023 (Exercise) | 25 mg/kg | Intraperitoneal (IP) | Twice daily (ZT0 + ZT12) | Variable (acute + chronic) | 12% DMSO, 15% Cremophor in PBS |
| Billon et al., 2024 (Metabolic) | 25 mg/kg | Intraperitoneal (IP) | Twice daily | 28 days | 12% DMSO, 15% Cremophor in PBS |
| Xu et al., 2024 (Heart Failure) | 25 mg/kg | Intraperitoneal (IP) | Twice daily (ZT0 + ZT12) | 6 weeks | 12% DMSO, 15% Cremophor in PBS |
Several important details emerge from these protocols. First, every published study used intraperitoneal injection, not under-skin injection or oral use. IP injection delivers the compound directly into the abdominal cavity, providing rapid absorption but representing a route of use that is standard in rodent research yet impractical for human use.
Second, the dosing schedule was consistently twice daily, timed to the beginning and midpoint of the light/dark cycle (ZT0 and ZT12), suggesting that the compound’s pharmacokinetics need split dosing to keep effective plasma levels. Third, the vehicle form—12% DMSO and 15% Cremophor EL in PBS—was necessary to solubilize SLU-PP-332 for injection, reflecting the compound’s limited aqueous solubility.
The stock solution was prepared at 5 mg/mL, stored at −20°C as DMSO stock, diluted with Cremophor before use, and refrigerated at 4°C for no more than five days before final dilution in PBS (Xu et al., 2024).
Allometric Dose Scaling: Why Mouse Doses Cannot Be Directly Applied to Humans
A common and dangerous error in the research chemical community is directly converting mouse mg/kg doses to human doses by simple body weight multiplication. This approach is pharmacologically incorrect. Mice have greatly higher body rates per kilogram of body weight than humans, meaning they clear drugs much faster. The FDA-recommended allometric scaling factor for converting mouse doses to human equivalent doses is division by 12.3.
Thus, a 25 mg/kg mouse dose would scale to about 2 mg/kg in humans, or roughly 140–160 mg for a 70–80 kg adult. However, this calculation is purely mathematical and does not account for differences in absorption, distribution, body function, receptor response, or toxicity between species. It should not be interpreted as a recommended human dose.
Anecdotal Community Protocols
Despite the absence of human safety data, an underground community of self-experimenters has emerged, sharing dosing protocols on forums and social media. Often reported anecdotal doses range from 10 mg to 30 mg daily, often gave subcutaneously. Some users report splitting doses morning and evening to mirror the twice-daily lab protocol.
These are entirely unvalidated practices based on personal experimentation rather than controlled clinical study, and they carry major unknown risks.
There is no set up safe human dose for SLU-PP-332. All lab research used intraperitoneal injection in mice at 25 mg/kg twice daily. Allometric dose scaling provides mathematical estimates only and does not set up safety. Any human use of this compound is entirely experimental and unsupervised. Consult a qualified healthcare professional before considering any research compound.
What Are the Side Effects of SLU-PP-332?
The honest answer to this question is that the side effect profile of SLU-PP-332 in humans is completely unknown. No human clinical trial—not even a Phase I safety study—has been conducted. What we can discuss is the safety data created from lab animal studies and the theoretical concerns that pharmacologists have raised based on the compound’s mechanism of action.
Preclinical Safety Data
Across the published mouse studies, the safety signals have been often reassuring at the doses tested. In the six-week heart failure study (the longest published treatment duration), mice got SLU-PP-332 at 25 mg/kg intraperitoneally twice daily for 42 consecutive days. The researchers explicitly stated that “no overt toxicity” was saw.
Specific safety metrics included no major changes in clinical chemistry parameters, no adverse effects on food intake or body weight in sham-operated (healthy) animals, no changes in locomotor activity, and preservation of lean body mass during fat loss in the body syndrome study. Also, the fat loss saw in obese mice was driven entirely by reduced adiposity rather than muscle wasting, which would have suggested catabolic toxicity (Billon et al., 2024; Xu et al., 2024).
Theoretical Safety Concerns
Despite the favorable lab safety profile, several theoretical concerns deserve careful consideration. First, chronically starting body pathways that increase energy-cell activity and fatty acid oxidation could possibly increase reactive oxygen species (ROS) production, adding to oxidant stress over long treatment durations. Second, while ERR agonism downregulated cell cycle genes in cardiomyocytes (which was considered beneficial for preventing heart failure progression), the long-term results of chronically suppressing cell cycle activity in other tissues are unknown.
Third, ERRs are expressed in many tissues beyond skeletal muscle and heart—including kidney, liver, and brain—and the effects of chronic pan-ERR start on these organs have not been comprehensively characterized.
Fourth, there is a pharmacokinetic concern. The vehicle form used in animal studies (DMSO and Cremophor EL) is not suitable for human use due to the known toxicity of Cremophor EL, which has been linked with hypersensitivity reactions, nephrotoxicity, and neurotoxicity in clinical settings. Any future human form would need a different supply vehicle, and the pharmacokinetics and safety profile could change largely as a result.
Unknown Long-Term Risks
The longest published SLU-PP-332 treatment study lasted six weeks in mice, which corresponds to a relatively modest duration in the context of chronic human therapy. Long-term carcinogenicity studies, fertility toxicity studies, and chronic organ toxicity assessments have not been published. The experience with Cardarine (GW501516)—which showed favorable short-term body effects but developed carcinogenicity signals in longer-term studies—serves as a cautionary example of why short-term lab safety data cannot be extrapolated to predict long-term safety.
SLU-PP-332 showed no overt toxicity in mouse studies lasting up to six weeks. However, the human safety profile is entirely unknown. Theoretical concerns include possible oxidant stress from chronic body start, unknown effects on non-target tissues, and the absence of long-term carcinogenicity data. The Cardarine precedent underscores why favorable short-term safety data does not guarantee long-term safety.
Can SLU-PP-332 Treat Heart Failure? What the Circulation Study Revealed
The January 2024 publication in Circulation—one of the world’s most prestigious cardiology journals—represents the most clinically major study on SLU-PP-332 to date. Led by a multi-institutional team including researchers from Baylor College of Medicine, Washington University, the Salk Institute, and the University of Florida, this paper provided the first direct pharmacological evidence that ERR agonism could be a viable treatment strategy for heart failure.
The Heart Failure Problem
Heart failure affects an estimated 6.5 million Americans and 23 million people worldwide, with projections exceeding 8 million U.S. cases by 2030. Despite advances in pharmacotherapy including beta-blockers, ACE inhibitors, ARBs, SGLT2 inhibitors, and sacubitril/valsartan, the five-year survival rate remains about 50%—comparable to many cancers. A hallmark of heart failure is progressive body remodeling, wherein the failing heart loses its power to efficiently use fatty acids as fuel and energy-cell function deteriorates.
This body dysfunction both reflects and accelerates the transition from compensated cardiac stress to decompensated heart failure (Xu et al., 2024).
Study Design and Key Results
The researchers used transaortic constriction (TAC) in mice, a well-set up surgical model that creates pressure overload on the left ventricle and progressively induces heart failure over four to six weeks. Both SLU-PP-332 and SLU-PP-915 were gave starting one day after surgery at 25 mg/kg IP twice daily. The results were striking across multiple endpoints.
Vehicle-treated mice showed progressive decline in ejection fraction from about 68% to 34% over six weeks. Mice treated with SLU-PP-332 kept greatly higher ejection fraction, and SLU-PP-915 showed even stronger gain, reaching significance as early as two weeks post-surgery. Both compounds reduced cardiac fibrosis, as showed by Masson trichrome staining, and decreased expression of cardiac stress markers (Nppa and Nppb).
Most importantly, ERR agonist-treated mice showed greatly improved survival compared to vehicle-treated controls.
The Metabolic Rescue Mechanism
Full metabolomics test of heart tissue revealed the mechanism underlying these cardioprotective effects. Six-week TAC induced dramatic changes in cardiac metabolite profiles, with 112 lipid and fatty acid metabolites decreased in failing hearts. In ERR agonist-treated animals, only 5 lipid/FA metabolites were decreased—representing a near-complete normalization of lipid body function.
Similarly, 46% of TCA cycle and oxidant phosphorylation metabolites were disrupted by TAC, but only 8% were affected in the treatment group. This body rescue was accompanied by preserved energy-cell ultrastructure on electron microscopy—treated hearts showed intact cristae and organized energy-cell architecture, in stark contrast to the fragmented, disorganized mitochondria characteristic of untreated failing hearts (Xu et al., 2024).
The Circulation authors stated: “ERR agonists keep oxidant body function, which confers cardiac protection against pressure overload-induced HF in vivo. Our results provide direct pharmacologic evidence supporting the further growth of ERR agonists as novel HF therapeutics.” This conclusion, published in a journal with an impact factor exceeding 35, represents a major endorsement of the treatment possible of ERR agonism for heart disease.
Is SLU-PP-332 Banned? WADA Status and Legal Considerations
The control and legal status of SLU-PP-332 depends entirely on the context in which the compound is being considered. For competitive athletes, research institutions, and personal consumers, the rules are very different.
WADA Prohibited List Status
SLU-PP-332 is explicitly listed on the World Anti-Doping Agency (WADA) Prohibited List under category S4: Hormone and Body Modulators. This prohibition applies at all times, both in-competition and out-of-competition, meaning that any athlete subject to WADA-governed drug testing who tests positive for SLU-PP-332 or its metabolites would face a doping violation and possible multi-year ban from competition.
The prohibition reflects WADA’s assessment that the compound’s showed power to enhance endurance and body performance represents an unacceptable performance-enhancing advantage in sport.
Anti-doping laboratories have already developed validated detection methods for both SLU-PP-332 and SLU-PP-915. A 2026 study by Möller, Krug, and Thevis in Rapid Communications in Mass Spectrometry characterized the in vitro body function of both compounds and identified specific metabolite signatures that can be detected in natural samples. A separate study by Avliyakulov, Sobolevsky, and Ahrens (2026) in Drug Testing and Test further validated these detection methods for doping control purposes.
United States Legal Status
In the United States, SLU-PP-332 is not a controlled substance under the Controlled Substances Act. It is not scheduled by the DEA and is not prohibited from sale or possession for research purposes. It occupies the legal category of a “research chemical”—a compound that can be legally bought, had, and used strictly for laboratory and experimental purposes but is not approved for human consumption.
This distinction is key. The compound carries no FDA approval, has no recognized medical sign, and cannot be legally marketed as a dietary supplement, food additive, or treatment drug. Legitimate suppliers label SLU-PP-332 as “For Research Purposes Only” and “Not for Human Consumption,” and any supplier marketing it for human use would be operating in violation of federal regulations.
International Regulatory Variation
Control frameworks for research chemicals vary greatly by country. Some jurisdictions have enacted broader prohibitions on novel psychoactive and pharmacologically active substances, which could cover compounds like SLU-PP-332 even outside the context of competitive athletics. Researchers and consumers should verify the specific regulations in their jurisdiction before getting this compound.
The rapidly evolving control landscape around exercise mimetics and body modulators means that the legal status could change with relatively short notice.
Buying SLU-PP-332 for Research: What to Look For
For researchers conducting legitimate lab studies, sourcing high-quality SLU-PP-332 is essential for creating reproducible and meaningful data. The research chemical market varies enormously in quality, purity, and reliability, and the results of using contaminated or mislabeled compounds extend beyond wasted experiments to possibly misleading scientific conclusions.
Certificate of Analysis (COA) Requirements
The single most important document when assessing any research chemical supplier is the Certificate of Test. A legitimate COA should include HPLC (high-performance liquid chromatography) purity data confirming greater than 98% purity, mass spectrometry data confirming cell-level identity, batch-specific testing results rather than generic records, and ideally third-party analytical check from an independent laboratory.
If a supplier cannot provide a current, batch-specific COA upon request, this represents a major red flag regardless of pricing or marketing claims.
Supplier Evaluation Checklist
Beyond the COA, several more factors distinguish reliable research chemical suppliers from questionable ones. Look for US-based operations with transparent business registration, consistent inventory supply rather than dropshipping from overseas manufacturers, responsive customer support with technical knowledge of the compounds they sell, proper labeling stating “For Research Purposes Only” and “Not for Human Consumption,” and clear terms of service that restrict sales to legitimate research uses.
Transparent pricing is also important—dramatically low prices often show either diluted product, lower purity, or contamination with synthesis byproducts.
Storage and Handling
Proper storage is essential for keeping compound integrity. SLU-PP-332 should be stored in a cool, dark, and dry environment. For long-term storage, refrigeration (2–8°C) or freezing (−20°C) is recommended. Once mixed in DMSO or other solvent systems, the solution should be aliquoted to minimize freeze-thaw cycles and used within the timeframes set up in the published literature—often within five days when stored at 4°C in the DMSO/Cremophor vehicle (Xu et al., 2024).
Standard laboratory personal protective equipment including gloves and safety glasses should be worn when handling the compound.
Frequently Asked Questions About SLU-PP-332
Key Takeaways: SLU-PP-332 in 2025
SLU-PP-332 represents one of the most scientifically compelling exercise mimetic compounds to emerge from academic research in the past decade. Its power to start estrogen-related receptors and trigger the genetic programs linked with aerobic exercise has produced notable lab results across three distinct treatment areas: endurance boost, body syndrome gain, and heart failure cardioprotection.
The publication of the heart failure data in Circulation—a top-tier journal with an impact factor exceeding 35—lends specific credibility to the compound’s treatment possible and has catalyzed major interest from both the scientific community and the broader public.
However, the current reality of SLU-PP-332 must be understood within its proper context. Every piece of effect data comes from mouse models and cell lines. No human clinical trial has been conducted. The compound is not FDA-approved for any sign. Its safety profile in humans is entirely unknown, and the longest published treatment duration in animals is just six weeks.
The experience with Cardarine—a compound with similarly impressive short-term lab results that was finally abandoned due to carcinogenicity concerns—provides an important reminder that lab promise does not guarantee clinical success.
For the research community, SLU-PP-332 and its successor SLU-PP-915 represent valuable pharmacological tools for studying ERR biology, energy-cell body function, and the cell-level mechanisms of exercise adaptation. For patient populations with limited exercise capacity—including the elderly, post-surgical patients, and people with severe heart failure—the concept of pharmacological exercise mimicry holds genuine treatment possible that justifies continued study.
For healthy people seeking performance boost, the risk-benefit calculation of using an unvalidated lab compound without human safety data is fundamentally different and demands extreme caution.
The future of this field is already taking shape. SLU-PP-915’s showed oral uptake addresses one of SLU-PP-332’s key pharmacokinetic limitations. Anti-doping detection methods are being developed in anticipation of athletic misuse. And the broader scientific community continues to explore ERR agonism as a treatment strategy across body disease, neurodegeneration, and aging.
Whether SLU-PP-332 itself or a descendant compound eventually enters human clinical trials, the foundational science it has created has permanently expanded our grasp of how cellular body function can be pharmacologically reprogrammed to mimic the benefits of physical exercise.
References
- Billon C, Sitaula S, Banerjee S, Welch R, Elgendy B, Hegazy L, Oh TG, Kazantzis M, Chatterjee A, Chrivia J, Hayes ME, Xu W, Hamilton A, Huss JM, Zhang L, Walker JK, Downes M, Evans RM, Burris TP. Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity. ACS Chem Biol. 2023;18(4):756-771. doi:10.1021/acschembio.2c00720
- Billon C, Schoepke E, Avdagic A, Chatterjee A, Butler AA, Elgendy B, Walker JK, Burris TP. A Synthetic ERR Agonist Alleviates Metabolic Syndrome. J Pharmacol Exp Ther. 2024;388(2):232-240. doi:10.1124/jpet.123.001733. PMID: 37739806.
- Xu W, Billon C, Li H, Wilderman A, Qi L, Graves A, Dela Cruz Rideb JR, Zhao Y, Hayes M, Yu K, Losby M, Hampton CS, Adeyemi CM, Hong SJ, Nasiotis E, Fu C, Oh TG, Fan W, Downes M, Welch RD, Evans RM, Milosavljevic A, Walker JK, Jensen BC, Pei L, Burris T, Zhang L. Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function. Circulation. 2024;149(3):227-250. doi:10.1161/CIRCULATIONAHA.123.066542
- Hampton CS, Sitaula S, Billon C, Haynes K, Avdagic A, Wanninayake U, Adeyemi CM, Chatterjee A, Griffett K, Banerjee S, Burris SL, Schoepke E, Boehm T, Bess A, de Vera IMS, Burris TP, Walker JK. Development and pharmacological evaluation of a new chemical series of potent pan-ERR agonists, identification of SLU-PP-915. Eur J Med Chem. 2023;258:115582. doi:10.1016/j.ejmech.2023.115582
- Conroy G. Why is exercise good for you? Scientists are finding answers in our cells. Nature. 2024;629(8010):26-28. doi:10.1038/d41586-024-01200-7
- Burris TP, de Vera IMS, Cote I, Flaveny CA, Wanninayake US, Chatterjee A, Walker JK, et al. International Union of Basic and Clinical Pharmacology CXIII: Nuclear Receptor Superfamily—Update 2023. Pharmacol Rev. 2023;75(6):1233-1318. doi:10.1124/pharmrev.121.000436
- Billon C, Appourchaux K, Côté I, Burris TP. An orally active estrogen receptor-related receptor agonist, SLU-PP-915, enhances aerobic exercise capacity. J Pharmacol Exp Ther. 2026;393(1):103787. doi:10.1016/j.jpet.2025.103787
- Möller T, Krug O, Thevis M. In Vitro Metabolism and Analytical Characterization of SLU-PP-332 and SLU-PP-915: Novel Pan-ERR Agonists With Doping Potential. Rapid Commun Mass Spectrom. 2026;40(8). doi:10.1002/rcm.70039
- Avliyakulov NK, Sobolevsky T, Ahrens E. Analysis and Identification of In Vitro Metabolites of Exercise Mimetic SLU-PP-332 ERRα/β/γ Agonist for Doping-Control Purposes. Drug Test Anal. 2026.
- Hagiu BA. Can SLU-PP-332 be a new drug to prevent COVID-19? Med Hypotheses. 2024;187:111362. doi:10.1016/j.mehy.2024.111362
- Losby M, Hayes M, Valfort A, Sopariwala DH, Sanders R, Walker JK, Xu W, Narkar VA, Zhang L, Billon C, Burris TP. The Estrogen Receptor-Related Orphan Receptors Regulate Autophagy through TFEB. Mol Pharmacol. 2024;106(4):164-172. doi:10.1124/molpharm.124.000889
- Wang XX, Myakala K, Libby AE, et al. Estrogen-Related Receptor Agonism Reverses Mitochondrial Dysfunction and Inflammation in the Aging Kidney. Am J Pathol. 2023;193(12):1969-1987. doi:10.1016/j.ajpath.2023.07.008
