SLU-PP-332: benefits, dosage, side effects and what the research shows

SLU-PP-332 is a laboratory compound designed at Saint Louis University to activate a family of proteins called estrogen-related receptors, or ERRs. In the paper that introduced it in 2023, the researchers described it as a pan-agonist: it activates all three ERRs (ERRα, ERRβ and ERRγ) but is most potent at ERRα. They reported that it had good enough pharmacokinetic properties to be used as a research tool in living mice, where it increased oxidative muscle fibres and running endurance ^[1].

The “SLU” in the name stands for Saint Louis University, and “PP” is an internal code. Chemically it is an acyl hydrazone with the formula C18H14N2O2 and a molecular weight of about 290. A 2026 review of ERR agonists groups it with other acyl hydrazones ^[11].

Its main use so far is as a chemical probe: a tool that lets scientists switch on ERR signalling and watch what happens. A 2026 paper that explored changes to its structure called it a well-established exercise mimetic and a widely used probe for ERR activation, while noting that the features controlling its potency and drug-like properties had not previously been worked out ^[7].

No. A peptide is a chain of amino acids, and SLU-PP-332 contains none. It is a small synthetic molecule built from a naphthalene ring and a hydroxybenzoyl group joined by a hydrazone link. Searches for the “SLU-PP-332 peptide” reflect where it is sold rather than what it is.

It appears on PepFinder because the stores that sell research peptides also sell it, as capsules and as injectable products, and because buyers compare it with metabolic peptides such as MOTS-c. Listing it lets buyers compare prices and testing alongside those products, and lets us set out what the evidence does and does not show.

Despite their name, the estrogen-related receptors do not bind oestrogen. They are “orphan” nuclear receptors: proteins that sit on DNA and switch groups of genes on, without a known natural hormone that controls them. They are most active in tissues with high energy demand, such as heart, skeletal muscle and liver, where they regulate the genes for building mitochondria, burning fat and running the cell’s energy chain ^[11].

As an SLU-PP-332 ERR agonist, the compound increases this activity. In a mouse muscle cell line it increased mitochondrial function and cellular respiration. In mice, a single dose switched on genes that are normally induced by a bout of aerobic exercise, including Ddit4, and this effect depended on ERRα: mice lacking ERRα in muscle did not gain endurance when treated ^[1]. In heart muscle cells, the ERR agonists also switched on TFEB, a master regulator of autophagy, the cell’s recycling process ^[12].

In heart studies the picture differed by receptor. Using mice and cells lacking specific ERRs, researchers found that ERRγ, not ERRα, was the main route for the protective effects of SLU-PP-332 and a related compound in failing hearts ^[3]. The receptors therefore do different jobs in different tissues, and a drug that activates all three at once affects many organs.

Claimed SLU-PP-332 benefits fall into four groups: endurance, fat loss and metabolic health, heart protection, and kidney ageing. Each rests on mouse studies, most from the laboratories that developed the compound, and several authors declare stock in companies developing ERR agonists ^[1][6]. A 2026 systematic review of the preclinical evidence concluded that clinical trials are needed to confirm efficacy and safety in humans ^[10].

So when people ask what SLU-PP-332 does, the accurate answer is what it did in mice and cells. It has not been shown to do any of these things in people.

The exercise-mimetic label comes from the 2023 study. Mice given SLU-PP-332 by injection into the abdominal cavity (intraperitoneal) twice a day had more type IIa muscle fibres, the oxidative fibres that resist fatigue, and ran further and for longer on a treadmill before exhaustion than untreated mice ^[1]. Its muscle genes shifted towards the pattern seen after aerobic exercise.

“Exercise mimetic” means that some molecular and endurance effects of training were reproduced in sedentary mice. It does not mean the compound replaces exercise. Exercise affects the heart, blood vessels, bones, brain and mood through many pathways, and the mouse studies measured a few muscle and metabolic outcomes. A newer, orally active relative, SLU-PP-915, has since been reported to improve endurance to a similar degree, and to add to the effect of training on some muscle genes ^[6].

One study used human cells. Muscle precursor cells taken during hip surgery from inactive women and treated with SLU-PP-332 in the laboratory showed higher levels of exercise-related proteins, less oxidative stress and better formation of muscle fibres ^[5]. These were cells in a dish, not a treatment given to people.

A 2024 study tested SLU-PP-332 in two mouse models of obesity. Mice made obese on a high-fat diet were given 50 mg/kg by intraperitoneal injection twice a day for 28 days while staying on the diet. They lost weight progressively and after 28 days weighed about 12% less than untreated obese mice. Untreated mice gained about 5 g of fat over the period, while treated mice gained less than 0.5 g ^[2].

The treated mice burned more energy and used more fat as fuel, with no significant change in food intake or lean mass. Their insulin sensitivity also improved. In genetically obese ob/ob mice, 12 days of treatment reduced fat mass, although body weight only trended lower ^[2]. The authors concluded that ERR activation may be a way to treat metabolic syndrome and obesity, which remains a hypothesis for people.

SLU-PP-332 weight loss in mice therefore came with higher energy use rather than lower food intake. Approved weight-loss medicines such as tirzepatide reached the market only after large human trials, a stage SLU-PP-332 has not begun. Whether the same happens in people, at what dose, and with what side effects, is unknown.

In mice with heart failure caused by narrowing the aorta, SLU-PP-332 and SLU-PP-915 given by intraperitoneal injection twice a day for six weeks improved ejection fraction, reduced scarring and increased survival, without changing heart muscle thickening. The hearts showed more fat-burning and mitochondrial gene activity ^[3].

In 21-month-old mice, eight weeks of SLU-PP-332 reversed age-related increases in protein leakage into urine, loss of filtering cells, mitochondrial dysfunction and inflammation in the kidney. The authors noted that ERR levels fall in ageing human and mouse kidneys and are preserved by lifelong calorie restriction, and described ERR agonists as calorie-restriction mimetics ^[4].

No. A search of ClinicalTrials.gov on 24 September 2026 for “SLU-PP-332” returned no registered studies ^[13], and we found no human study of the compound in PubMed. The 2026 systematic review covered animal and cell studies only and called for clinical trials ^[10].

People searching for an SLU-PP-332 clinical trial or its ClinicalTrials.gov entry are often checking claims on product pages. If a seller says the compound has been tested in people, ask for the trial registration number. We could not find one. Our methodology page explains how we handle claims like this.

There is no controlled human evidence on how long SLU-PP-332 takes to work or what results to expect. In mice, a single dose changed muscle gene activity within hours, endurance was tested after about one to two weeks of treatment, fat and weight changes were measured over 12 to 28 days ^[1][2], and heart and kidney effects over six to eight weeks ^[3][4].

SLU-PP-332 before and after photos and online reviews cannot answer the question. They are uncontrolled, the product’s identity and strength are rarely tested, and diet and training usually change at the same time. Given the oral absorption problem described below, a capsule product may deliver little of the compound.

Every published animal study of SLU-PP-332 gave it by intraperitoneal injection, dissolved in mixtures of DMSO with detergents such as Tween or Cremophor ^[1][2][3]. No published study has given it by mouth, by injection under the skin, or as a capsule or tablet.

On SLU-PP-332 oral bioavailability, its developers are direct: in a 2026 paper they wrote that SLU-PP-332 improves aerobic performance in mice but lacks oral bioavailability, which is why they developed SLU-PP-915, a chemically different compound that does work by mouth ^[6]. A separate structure study found analogues with better solubility or metabolic stability, which suggests these are weak points of the original molecule ^[7].

That matters for SLU-PP-332 capsules, which are among the most widely sold forms. The developers’ own statement implies that little of an oral dose reaches the bloodstream, and no one has published human absorption data. For an SLU-PP-332 injectable, the studies used intraperitoneal injection with solvents not intended for human use, so the research does not describe a human injectable form either.

On the question of SLU-PP-332 oral or injectable, then, the only published route is intraperitoneal injection in mice, and the developers say oral use does not work well. Neither route has been studied in people.

All published doses are from mice, given by intraperitoneal injection. The 2023 endurance study used 30 mg/kg for pharmacokinetic sampling and 50 mg/kg twice a day for 7 to 15 days for its main experiments, with some tests at 25 mg/kg ^[1]. The 2024 obesity study used 50 mg/kg twice a day for 28 days ^[2]. The heart failure study used 25 mg/kg twice a day for six weeks ^[3], and the kidney study 25 mg/kg once a day for eight weeks ^[4].

No human SLU-PP-332 dosage has been established, because no human study exists. There is no evidence-based SLU-PP-332 dosage per day, oral dosage per day, tablet dosage or injection dosage for people, and online dosing charts are not based on research. Animal doses in mg/kg should not be converted into human doses, and PepFinder does not recommend any dose.

Label arithmetic is a separate question. A product labelled 250 mcg per capsule contains 0.25 mg per capsule by definition, but the label does not say how much is absorbed. For a powder vial, 10 mg dissolved in 2 mL gives 5 mg per mL, or 0.05 mg per unit on a U-100 insulin syringe. The SLU-PP-332 dosage calculator does this sum for other sizes, and our guide to bacteriostatic water covers diluents. The mouse studies dissolved it in DMSO-based laboratory vehicles rather than water or saline ^[1][3].

There are no human safety data, so SLU-PP-332 side effects in people are unknown. In mice given 50 mg/kg twice daily for 10 days, the developers observed no overt toxicity, and blood counts and electrolytes were normal ^[1]. Over 28 days, only relatively minor changes in plasma cholesterol and liver enzymes were reported ^[2]. The heart failure authors said they saw no overt adverse effects but that more detailed study was needed ^[3]. None of these was a formal toxicology study of the kind regulators require before a first human dose.

The biology gives reasons for caution. ERRs are highly expressed in skeletal muscle, heart, brain, fat and liver and control energy genes there ^[1][11], so activating all three receptors throughout the body will affect many organs at once. In human liver preparations, SLU-PP-332 was broken down into at least nine metabolites ^[9], and another laboratory identified 22 ^[8]. What those metabolites do in people has not been studied.

The practical risks are those of any unlicensed product: wrong identity, wrong amount and contamination, plus sterility and endotoxin for injectables. Our guides to third-party peptide testing and how to read a COA explain what a lab report can confirm.

No SLU-PP-332 half-life has been published for people or, as far as we could find, for mice. The 2023 study measured levels only at a few time points: two hours after a 30 mg/kg intraperitoneal dose, concentrations were about 0.6 micromolar in muscle and 0.2 micromolar in plasma ^[1]. That is enough to show the compound reaches muscle, but not how long it lasts.

For storage, the usual practice is to keep vials and capsules cool, dry and away from light, and to refrigerate a vial once mixed. See how to store peptides; the same principles apply to small molecules sold alongside them.

Both are sold as exercise mimetics, but they are different kinds of molecule. MOTS-c is a natural 16-amino-acid peptide encoded in mitochondrial DNA that acts through AMPK, the cell’s energy sensor. In mice it prevented diet-induced obesity and insulin resistance ^[14] and improved running capacity at all ages, and in people its levels rise during exercise ^[15]. SLU-PP-332 is a synthetic small molecule that activates ERRs ^[1].

No study has compared them or tested them together. Neither has published human efficacy data. MOTS-c at least has measurements of its natural levels in people, while SLU-PP-332 has none. Claims that one is stronger than the other, or that they combine well, are not based on research. The small molecule 5-amino-1MQ, which blocks a different enzyme, is also compared with both online, and has likewise only been studied in animals.

SLU-PP-332 is not an approved medicine in the UK, US, EU, Canada, Australia or New Zealand, and no human trial has been registered ^[13]. We did not find a regulator statement that names it specifically. How each country treats unapproved substances sold as research chemicals is covered on our legal status pages, including the UK and Australia.

Anti-doping laboratories regard it as a substance with doping potential. Two laboratories published methods in 2026 to identify its breakdown products in human liver preparations, for use in sports drug testing ^[8][9]. We have not confirmed whether SLU-PP-332 is named on the World Anti-Doping Agency Prohibited List, so tested athletes should check with their national anti-doping organisation.

PepFinder does not sell SLU-PP-332. You can compare SLU-PP-332 prices across research suppliers, including SLU-PP-332 UK suppliers and SLU-PP-332 prices in Australia, where imported unapproved products are regulated. Check local law first.

Look for batch-specific third-party results, and see which vendors use third-party tested batches. Our guide on how to spot a fake peptide supplier covers warning signs, and our news page follows regulator actions on unapproved products.