PT-141

PT-141 (bremelanotide) is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (alpha-MSH) and an active metabolite of melanotan II. It acts as a non-selective agonist of the melanocortin receptors (MC1R, MC3R, MC4R, MC5R; it does not meaningfully activate MC2R), with primary relevant activity at the MC3 and MC4 receptors. It is reported to act centrally within the hypothalamus and limbic system, where MC4R signaling is thought to modulate dopaminergic pathways implicated in sexual arousal and desire, rather than through peripheral vasodilation.

Human evidence

FDA-approved (as Vyleesi) for one specific indication; supported by two identical Phase 3 randomized, placebo-controlled trials (RECONNECT program)

Regulatory status

FDA-approved in June 2019 as Vyleesi (bremelanotide injection) for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women; administered by subcutaneous injection. It is also sold as an unapproved "research chemical," which is not an FDA-authorized use. PT-141 is not among the peptides under FDA Pharmacy Compounding Advisory Committee review for the Section 503A Bulk Drug Substances List (April 16, 2026 Federal Register notice; July 2026 and early-2027 meetings), consistent with its status as an already-approved drug; its parent compound melanotan II is scheduled for the early-2027 (before end of February 2027) review.

• —Studied as an on-demand treatment for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, the basis of its FDA approval (Phase 3 RECONNECT program).
• —Investigated mechanistically as a probe of central melanocortin (MC3R/MC4R) signaling in sexual arousal and desire pathways.
• —Explored in earlier research for erectile dysfunction, including intranasal formulations, before development focused on female HSDD.

• ⚠Per the FDA label, the most common adverse reactions (incidence greater than 4 percent) are nausea (reported by roughly 40 percent of trial participants), flushing, injection-site reactions, headache, and vomiting.
• ⚠Vyleesi transiently raises blood pressure and lowers heart rate after each dose (usually returning to baseline within about 12 hours); per the label it is contraindicated in patients with uncontrolled hypertension or known cardiovascular disease, with dosing limited to no more than one dose per 24 hours and no more than eight doses per month.
• ⚠Focal hyperpigmentation (including the face, gingiva, and breasts) was reported in about 1 percent of patients receiving up to eight doses per month, more likely with darker skin or more frequent dosing, and was not confirmed to resolve in all patients after discontinuation.
• ⚠Safety data derive from the approved subcutaneous product studied in premenopausal women; the purity and safety of unapproved 'research' PT-141 (including nasal-spray forms) have not been established by regulators.