What Is SLU-PP-332? The “Exercise in a Pill” Compound

Exercise naturally switches on ERR signaling in muscle. SLU-PP-332 activates all three ERR types (α, β and γ), with the strongest effect on ERRα.

• More mitochondria: ERR activation increases mitochondrial biogenesis, the creation of new mitochondria.
• Fat-burning muscle: it shifts muscle toward oxidative, endurance-type fibers that burn more fat.
• Higher energy use: in mice, it increased resting energy expenditure.

Because this mirrors what endurance training does, SLU-PP-332 is called an exercise-mimetic.

Endurance. In a 2023 study in ACS Chemical Biology, mice given SLU-PP-332 ran about 70% longer and 45% farther than untreated mice. The effect depended on ERRα.

Obesity. A 2023 study in the Journal of Biological Chemistry found that obese mice treated for 28 days lost about 12% of body weight, gained less fat and had better glucose tolerance, without eating less.

Heart failure. A 2023 Circulation study found that SLU-PP-332 and a related compound improved heart function and survival in mice with heart failure.

Humans. There are no human trials. No human safety, absorption or dosing data have been published, and no study is registered on ClinicalTrials.gov. In mouse studies it was given by injection, and researchers have reported that it is poorly absorbed when taken by mouth, which led them to develop an orally active successor, SLU-PP-915.

With no human studies, the safety of SLU-PP-332 is unknown. ERRs are active in many tissues, including the heart, liver and brain, so long-term activation could have effects that short mouse studies would not reveal. Because the compound is poorly absorbed orally, capsule products may also deliver much less than labeled, or contain other substances.

No. SLU-PP-332 is not an FDA-approved drug or supplement ingredient. It is sold only as a research chemical. Its patents are held by Saint Louis University, and no pharmaceutical partner has announced a human development program. Athletes should check WADA’s Prohibited List, which bans several exercise-mimetic metabolic modulators.

A cautionary comparison. GW501516 was once called an exercise pill too. Its developer stopped work after long-term animal studies found cancers in multiple organs. That history is a reminder that promising short-term mouse results do not show long-term safety.

SLU-PP-332 vs ATX-304. ATX-304 works on a different pathway (AMPK) and has reached early human testing, which puts it further along than SLU-PP-332. See our ATX-304 guide.

Products sold as SLU-PP-332 by research suppliers are laboratory chemicals, not medicines. They are not made under drug manufacturing rules, so quality varies a lot between vendors. If you are evaluating an SLU-PP-332 supplier for lab research, these are the checks that matter:

• Batch-specific COA: the certificate should match the lot number on your vial, not a generic sample.
• Independent lab: testing should come from a named third-party lab, ideally with a way to verify the report online.
• Identity, not just purity: HPLC purity alone does not confirm the right molecule; look for mass spectrometry (MS) identity confirmation.
• Endotoxin and sterility results: these matter for any injectable research material.
• Correct fill amount: the measured content should be close to the labeled milligrams.

Our Trusted Sources page lists vendors we track, with current community codes. Our guide to reading a certificate of analysis explains each line of a COA.

• SLU-PP-332 is a small molecule that activates estrogen-related receptors (ERRs).
• In mice, it increased running endurance by about 70% and reduced weight gain.
• There are no human trials and no human safety data.
• It is poorly absorbed orally; its developers created an oral successor, SLU-PP-915.
• It is not FDA-approved and is sold only as a research chemical.

What is SLU-PP-332?

SLU-PP-332 is an experimental small molecule that activates estrogen-related receptors, mimicking some effects of endurance exercise in mice.

Does SLU-PP-332 work in humans?

Unknown. It has never been tested in people, and no human safety or effectiveness data exist.

Is SLU-PP-332 a peptide?

No. It is a small molecule, although it is often sold by peptide suppliers.

Does SLU-PP-332 cause weight loss?

In obese mice, it caused about 12% weight loss over 28 days without reduced food intake. This has not been tested in people.

Is SLU-PP-332 FDA-approved?

No. It is not an approved drug or supplement and is sold only as a research chemical.

• ACS Chemical Biology – Billon et al. (2023), Synthetic ERRα/β/γ agonist induces an ERRα-dependent acute aerobic exercise response
• Journal of Biological Chemistry – Billon et al. (2023), A synthetic ERR agonist alleviates metabolic syndrome
• Circulation – Xu et al. (2023), ERR agonism reverses mitochondrial dysfunction and heart failure in mice
• Journal of Pharmacology and Experimental Therapeutics – Billon et al. (2025), SLU-PP-915, an orally active ERR agonist