The short version of this quarter's PT-141 news: the approved product's label stayed the same, and the biggest development was FDA pushing back on websites that sell PT-141 without a prescription. PT-141 is the development name for bremelanotide, a peptide studied for low sexual desire. Around that steady label, FDA sent warning letters to five online sellers, a lab study mapped how the molecule breaks down, and a skin-cancer charity warned about PT-141's tanning-drug relative.

As of September 23, 2026, the day this article was written, no new human trial of bremelanotide had been published this quarter, in women or in men.

Changelog

September 1 — FDA posted five warning letters that named PT-141. The letters, all dated August 24, went to online peptide sellers. Every one listed PT-141 among products FDA called unapproved new drugs, meaning medicines sold for use in people without the approval federal law requires (FDA warning letter, August 24, 2026). A warning letter states the agency's position; it isn't a court ruling. The FDA peptide warning letters explainer covers all five.

August 20 — a lab study mapped how bremelanotide breaks down. Chemists stress-tested the peptide with acid, alkali, oxidation, heat and light, and found eight degradation products, the new compounds that form as a drug falls apart. It was especially vulnerable to oxidation and also degraded under heat and light (Yuvaraaj and Sharma, Analytical Methods, 2026). This was test-tube chemistry, not a study in people. It does line up with the Vyleesi label's storage rules: at or below 77°F, never frozen, away from light.

July 23–24 — FDA's compounding advisers met on seven peptides, and bremelanotide wasn't one. This summer's headlines about FDA reviewing peptides mostly traced back to this Pharmacy Compounding Advisory Committee meeting on BPC-157, KPV, TB-500, MOTS-c, DSIP, Semax and Epitalon (FDA meeting page). The list it advises on, the 503A bulks list, is for ingredients that lack a USP or National Formulary monograph (an official quality standard) and are, in FDA's words, "not a component of an FDA-approved drug product" (FDA, current as of May 14, 2026). Bremelanotide is the active ingredient in Vyleesi. How the 503A bulks list works explains the rest.

July 7 — a skin-cancer charity warned about melanotan II, a tanning peptide and a close chemical relative of PT-141. The Skin Cancer Foundation said melanotan II is not FDA-approved for any use, pointed to case reports of melanoma and fast-changing moles (noting that case reports can't prove cause), and said online buyers may have no reliable way to know a product's purity, dose or contents (Skin Cancer Foundation, July 7, 2026). The statement didn't mention PT-141, and melanotan 2 side effects covers that separate record.

September 23 status — the Vyleesi label hasn't changed. DailyMed's prescribing information for Vyleesi, now marketed by Cosette Pharmaceuticals, still reads "Revised: 3/2024" (DailyMed), and Drugs@FDA lists no labeling supplement since October 23, 2020.

What PT-141 is, and what it's studied for

PT-141 is a melanocortin receptor agonist. In plain terms, it switches on receptors in the brain involved in sexual desire, instead of acting on blood flow the way sildenafil does. How PT-141 works walks through the biology.

Its core evidence is still two phase 3 trials called RECONNECT. They enrolled 1,267 premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD), which means persistent low desire that causes distress and isn't explained by another condition, a medication or relationship problems. About 58% of women on bremelanotide reported a meaningful benefit, compared with about 36% on placebo, and desire and distress scores moved modestly in the drug's favor (Kingsberg et al., Obstetrics & Gynecology, 2019). The RECONNECT walk-through has the full numbers.

In men, the evidence is older and thinner: small early studies of erectile response, and nothing new this quarter. Prescribing bremelanotide for a man is off-label, meaning outside the approved product's indication. PT-141 for men explains what those studies can and can't show.

What the PT-141 news means if you're considering it

The letters point at one real difference: the route. A vial from a website comes with a product page and little else. A prescribed medication comes with a named prescriber who reviewed your history, a licensed U.S. compounding pharmacy you can identify, a label with a lot number and storage instructions, and someone to call if something feels wrong.

The August breakdown study makes that last part less abstract. A peptide that degrades with heat, light and oxidation is only as good as the way it was made, shipped and stored. Fair questions for any prescriber: which pharmacy prepares it, how it should be stored, and whom to contact about a problem.

What to watch next

The first thing is a study FDA required when Vyleesi was approved: a trial in breastfeeding women measuring bremelanotide in breast milk (Vyleesi's 2019 approval letter). The registry lists a 10-woman study as completed on November 15, 2025, with no results posted (NCT06867835). The label still says there is no information on bremelanotide in human milk.

After that, watch for responses or close-out letters on the five warning-letter pages, and for new human data, especially in men, where the gap between how PT-141 is used and what has been tested is widest.

Vyleesi label and approval status in 2026

Vyleesi was approved on June 21, 2019, for premenopausal women with acquired, generalized HSDD. Its label says it is not indicated for postmenopausal women, for men, or to enhance sexual performance.

Through Promise, PT-141 is dispensed as a compounded medication, which is different from an FDA-approved product: the formulation offered here is not FDA-approved. Vyleesi's approval belongs to Vyleesi itself, a 1.75 mg single-dose autoinjector. It doesn't transfer to a pharmacy-prepared formulation, and formulations vary by pharmacy and prescription.

Nothing this quarter changed that picture. The August letters were about sellers marketing unapproved products straight to the public; they didn't announce a new rule for prescriptions. Regulatory status is one input into a clinical decision, not the whole of it. A licensed provider may still prescribe a compounded formulation when they judge it appropriate; that decision is between you and your doctor.

What a provider still weighs

The label's cautions didn't change, so the review didn't either. Vyleesi is contraindicated in uncontrolled high blood pressure and known cardiovascular disease, because each dose briefly raises blood pressure. In studies the peak rise was up to 6 mmHg systolic and 3 mmHg diastolic, usually back to baseline within 12 hours.

In the label's pooled trial table, nausea affected 40% of women on the drug versus 1.3% on placebo, and flushing 20.3% versus 0.3%. The label also reports focal hyperpigmentation, meaning darkened patches of skin or gums, in about 1% of women using up to eight doses a month, with higher risk from daily dosing. It warns that bremelanotide can significantly lower the body's exposure to oral naltrexone, and it advises effective contraception during use. PT-141 side effects covers each of these in depth.

A provider reads all of that against your own history and sets any dose. At Promise, a licensed provider reviews every request and may decline; not everyone qualifies.