PT-141
FDA ApprovedStrong EvidencePT-141 / Bremelanotide
The only centrally-acting FDA-approved treatment for female hypoactive sexual desire disorder — and the first peptide-based sexual-health drug, approved 2019, now sold freely by peptide vendors.
The first drug to treat low sexual desire by acting on the brain rather than the genitals — and FDA-approved for women with HSDD since 2019. It works on the same central circuits that make you want sex in the first place, not on blood flow (that's what Viagra does). The Phase 3 trials showed real but modest benefit — about half an extra satisfying sexual encounter per month compared to placebo. The main downside is nausea, which affects 40% of users and is dose-dependent. Men use it off-label for ED, with reasonable Phase 2 evidence. The chronic-use concern worth taking seriously: repeated doses cause focal skin darkening (hyperpigmentation), which is why the FDA limits it to 8 times per month. Vendors sell it as a research peptide, but it's a real prescription drug with a real approval — and real side effects.
Half-Life
~2.7 hours (subcutaneous, human PK data from clinical trials)
Molecular Weight
1025.19 g/mol
PT-141 (bremelanotide) is a cyclic heptapeptide melanocortin receptor agonist derived from the tanning peptide Melanotan II. Where Melanotan II (a linear peptide) was noted to cause spontaneous erections in early studies, a cyclic analog was developed specifically for sexual dysfunction. PT-141 binds MC3R and MC4R receptors in the central nervous system — primarily in the hypothalamus — activating brain-based sexual arousal pathways rather than acting on peripheral vasculature (as PDE5 inhibitors like sildenafil do). It received FDA approval in June 2019 as Vyleesi (1.75 mg SC) for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. **PT-141/bremelanotide is an FDA-approved prescription drug.** Vendors selling it as a research peptide are operating outside pharmaceutical regulations. For men, bremelanotide has completed Phase 2 trials showing efficacy in erectile dysfunction, but has not received FDA approval for this indication — that use is off-label.
Also Known As
Amino Acid Sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH (cyclic 7-amino acid peptide; cyclized via lactam bridge between Asp and Lys side chains)
Reconstitution
Available as pre-filled autoinjector (Vyleesi). Research peptide requires reconstitution with bacteriostatic water; typical concentration 1 mg/mL.
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