PT-141

PT-141 is the development name for bremelanotide, a synthetic ring-shaped peptide of seven amino acids that activates melanocortin receptors, mainly MC1R and MC4R at approved doses. The approved product is Vyleesi, marketed by Cosette Pharmaceuticals. Researchers describe bremelanotide as a variation of melanotan II designed for sexual stimulation: both act on melanocortin receptors, but only bremelanotide has an FDA-approved product.

Only for some women. Vyleesi is approved for premenopausal women with acquired, generalized HSDD: low sexual desire that causes marked distress or relationship difficulty, began after a time without problems, happens in every situation, and is not due to another medical or psychiatric condition, relationship problems, or a medicine. The label says it is not indicated in men, in postmenopausal women, or to enhance sexual performance. No approval establishes that it works in men.

No. The only FDA-approved bremelanotide product listed on DailyMed is the Vyleesi autoinjector, injected under the skin. An FDA import alert lists a “PT 141 Peptide” entry because there is no FDA-approved application in effect for “PT-141”; the approved product is Vyleesi, under the bremelanotide name. In August 2026, the FDA also warned three websites that their PT-141 products were unapproved new drugs, despite “research use only” labels.

Nausea is the main one: 40% of women in the Vyleesi trials, 13% needed anti-nausea medicine and 8% stopped because of it. It usually began within an hour of a dose and lasted about two hours, and it was most common after the first dose (21%), falling to about 3% after later doses. Taking ondansetron beforehand did not prevent it. Flushing, headache and injection-site reactions were also common. Blood pressure rises and heart rate drops for some hours after each dose, and some people develop darker patches on the face, gums or breasts that may not fade. With alcohol, flushing was more common than with alcohol alone, and headache more common than with bremelanotide alone.

The label’s directions, which your prescriber applies to you: one 1.75 mg injection under the skin of the abdomen or thigh, as needed, at least 45 minutes before expected sexual activity; no more than one dose in 24 hours; more than 8 doses a month is not recommended; and stop after 8 weeks if symptoms haven’t improved. How long the effect lasts after a dose is unknown. Blood levels peak about 1 hour after the injection, and the half-life is about 2.7 hours (range 1.9 to 4.0). Store it at or below 25°C (77°F), don’t freeze it, and keep it out of light. Follow your prescriber’s instructions.

No. Vyleesi is 1.75 mg of bremelanotide in 0.3 mL, ready to inject in a single-dose autoinjector that comes in cartons of 2 or 4; there is no vial and no water to add. A 10 mg powder vial is not an approved product, and the FDA has called such “PT-141” products unapproved new drugs. Its concentration depends on how much water is added, so unit readings don’t carry over from one to the other. The PT-141 10 mg calculator shows the mixing arithmetic for a vial; confirm any numbers with a licensed prescriber or pharmacist.