SLU-PP-332 Side Effects: What Is Reported, What Is Unknown, and Who Should Avoid It

That is the whole of what is reported. It is short because nobody has measured side effects in people: the list comes from prescriber experience, not from a trial, and prescriber experience detects common short-term effects well and rare or delayed ones poorly.

Safety claims for a medication normally rest on animal toxicology, controlled human trials, post-marketing reporting and clinical experience. For SLU-PP-332, most of those layers are missing.

The honest summary: a mouse literature that did not report harm, and an empty space where human safety data would be. "No harm reported in mice" is not the same as "safe in people," and exercise mimetics have a history of behaving differently in rodents and humans.

Why it behaves like a drug, not a peptide

SLU-PP-332 is not a peptide. It is a small synthetic organic molecule, built around a naphthalene ring and a phenol, designed to switch on the estrogen-related receptors ERRα, ERRβ and ERRγ. It is metabolised in the liver the way small-molecule drugs are, which is why the anti-doping papers studied human liver enzymes. That matters for how to think about its safety: the published work on it comes from pharmacology and medicinal chemistry, and it should be thought about the way any unstudied drug-like compound would be. It also lacks oral bioavailability, which is why Pepti supplies it as a subcutaneous injection. Is 5-Amino-1MQ a peptide explains why small molecules like this sit in a peptide catalog.

Cancer history

ERRα, the receptor SLU-PP-332 acts on most potently, is also a well-studied regulator of metabolism inside cancer cells. The effect of activating it in someone with an existing tumour has not been examined, in animals or people. That is not evidence that SLU-PP-332 causes or worsens cancer; it is an unexamined question about a receptor that tumours use. A personal history of cancer belongs on the intake, and a physician may decline. The wider reasoning is in can peptides cause cancer.

Heart history

The ERRs are among the main switches for fuel metabolism in heart muscle, and SLU-PP-332 acts on the heart's fuel metabolism. In a mouse model of pressure-overload heart failure (Circulation, 2024), ERR agonists improved heart function. But the effect in a healthy human heart, or in a person with a different heart condition, has not been measured. Anyone with a cardiac history should say so on the intake. Palpitations, chest pain or fainting while taking it should be reported, and chest pain or severe shortness of breath is a reason to call 911.

If you think you may have taken too much, for example by drawing the wrong amount, call Poison Control at 1-800-222-1222 and message your care team. Do not skip, double or change a dose to compensate.

Not every side effect is urgent. Message your care team through your account for:

• Injection-site reactions that keep happening despite rotating sites.
• Nausea or light-headedness that has not settled.
• Palpitations or a change in exercise tolerance you did not expect.
• Any new diagnosis, especially cancer or a heart condition.
• Any change in your medications, including starting a GLP-1 medication or anything that affects blood sugar.
• A pregnancy, or plans for one.
• A vial that looks different from the last one.

Your physician may revise your directions, change the product, or stop treatment. Do not change the dose yourself. When directions change, the new numbers are printed on the new label.

There is no established interaction list, because the trials that would produce one have not been run. That is why the intake asks for every medication and supplement you take, and why a physician reviews it rather than a form. There is no published data, in animals or humans, on using SLU-PP-332 with semaglutide or tirzepatide.

• Every human side effect. No human trial means no measured rate for anything, common or rare.
• Long-term safety. The longest treatment on record is eight weeks, in mice. Nothing about months of use in people has been studied.
• What happens when you stop. There is no described withdrawal, because stopping it has not been studied in people.
• Whether the cancer and heart cautions are real risks. They are questions about the receptors involved, not observed signals. They have not been ruled out either.
• How liver or kidney disease changes things. It is metabolised in the liver, but nobody has studied it in people with liver or kidney conditions.
• Interactions. No drug-interaction data exists.
• The right human dose. The mouse doses were set by body weight and given intraperitoneally, and do not convert into a human figure.

SLU-PP-332 has a well-characterised mouse pharmacology, some of it tested with knockout animals, and that work did not describe overt toxicity. It has nothing in people. The prescriber-reported side effects are mild and local, but they rest on clinical experience rather than measurement. Anyone describing SLU-PP-332 as shown to be safe in people is describing something that has not been published, and anyone describing it as shown to be dangerous is overstating it the other way.

The separate and non-theoretical risk is supply. SLU-PP-332 is sold widely as a research chemical, with no pharmacy accountable for identity, purity, sterility or concentration. For a compound with no human safety data, not knowing what is in the vial adds a second unknown on top of the first. The distinction is set out in research peptides vs prescription peptides, and Pepti's lot test results are at /quality/lab-results.

Where it stands with the FDA and anti-doping bodies

As of September 2026, SLU-PP-332 does not appear in any category of the FDA's 503A bulk drug substances list, updated 14 May 2026. It has never been flagged on the FDA's significant-safety-risks page and was not on the July 2026 advisory committee agenda. The FDA has not evaluated it in either direction: it is neither flagged as a safety concern nor reviewed for any positive list. It is prepared by a state-licensed pharmacy for an individual prescription, and compounded medications are not FDA approved.

For anti-doping, WADA prohibits exercise mimetics and metabolic modulators as a class, laboratories published detection methods for SLU-PP-332 and its metabolites in 2026, and the 2027 Prohibited List names SLU-PP-332 and SLU-PP-915 under S4.4. A standard workplace drug screen does not look for it. See do peptides show up on a drug test.

SLU-PP-332 is a 5 mL multi-dose vial at 2 mg/mL, 10 mg per vial. Pepti's typical directions are 0.25 mL, which is 25 units on a U-100 insulin syringe, under the skin once daily Monday through Friday, so each dose is 0.5 mg and a vial holds 20 doses, about four weeks. Your physician sets your directions after reviewing your intake, and they are printed on the vial. It costs $229 a month, all-in, covering medication, physician review, refill management and shipping, with no separate membership fee; Pepti is cash-pay and does not bill insurance. Vials ship refrigerated with ice packs, with sterile syringes and alcohol prep pads, and refills run every 28 days, one vial per fill, each reviewed by a physician. Bloodwork is not required for any Pepti treatment. If your physician wants labs for your care, they'll ask through your account.

1. Complete a free online intake covering your history, medications and what you want help with.
2. A physician licensed in your state reviews it, usually within 24 hours.
3. If it is appropriate, a PCAB-accredited, FDA-registered US 503A compounding pharmacy prepares it to that prescription. Lot test results are published at /quality/lab-results.
4. It ships refrigerated with your directions printed on the vial.
5. Your physician stays reachable for questions and side effects.

Pepti prescribes SLU-PP-332 in every state except Oklahoma, plus DC Step by step: how to get SLU-PP-332 prescribed online. The full reference is what is SLU-PP-332, and the comparison with the other metabolic options is MOTS-c vs SLU-PP-332 vs 5-Amino-1MQ.