PT-141 (Bremelanotide)

Grade A applies only to the FDA-approved Vyleesi product, approved on the basis of two large phase 3 randomized trials; it does not extend to research material.

Strengths: 10 mg
Also known as: Bremelanotide, Vyleesi (approved brand), Rekynda (former name), PT-141 (Palatin code)
Molecule: 7-amino-acid cyclic melanocortin agonist
Formula: C50H68N14O10
Mol. weight: 1025.16 g/mol
CAS: 189691-06-3
Sequence: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH

Origin

Developed by Palatin Technologies from Melanotan II; it differs from MT-2 only at one end (a free acid instead of an amide) and is thought to be an MT-2 metabolite. The sexual-arousal effect of α-MSH was first noted in rats in the 1960s.

How it works

Activates several melanocortin receptors (MC1R and MC3R–MC5R). Its effects on desire are attributed mainly to MC4R in the brain, acting on central pathways rather than blood flow. Activity at MC1R on skin pigment cells explains focal darkening of skin and gums.

What the research shows

Two identical 24-week phase 3 trials (RECONNECT, about 1,267 premenopausal women with hypoactive sexual desire disorder) found small but statistically significant gains in desire and reduced distress, without more satisfying sexual events; dropout was high. A 52-week extension found the gains held with no new safety signals. Early intranasal studies in men produced measurable erections, but FDA halted the intranasal program in 2007 over blood-pressure increases. Critics question how meaningful the effect size is, and there is no approval or phase 3 data in men or postmenopausal women.

Key studies

Kingsberg et al., Obstet Gynecol 2019 Two phase 3 RECONNECT trials: small significant gains in desire and less distress vs placebo.
Simon et al., Obstet Gynecol 2019 52-week open-label extension: gains held; no new safety signals.
Diamond et al., Int J Impot Res 2004 Intranasal phase 1/2 in men: erections measurable within about 30 minutes; flushing and nausea common.

Safety findings

On the label, nausea affected 40% of women (vs 1.3% on placebo), with flushing, injection-site reactions, headache and vomiting also common; 18% stopped because of side effects. The label describes a short-lived rise in blood pressure after each administration and is contraindicated with uncontrolled hypertension or heart disease. Focal darkening of the face, gums and breasts occurred, did not resolve in everyone, and was more common with more frequent administration; it also slows stomach emptying, affecting some oral drugs.

Regulatory status

The brand drug Vyleesi was FDA-approved in June 2019 for acquired, generalized hypoactive sexual desire disorder in premenopausal women; it is not approved for men, postmenopausal women or performance, and approval does not cover research powder. Bremelanotide is not on FDA's Category 2 list and can qualify as a 503A bulk substance as an approved-drug component. It is not named on the 2026 WADA list.

Catalog notes

Offered in 10 mg. Current lot PT141-0803 has a certificate (99.85% purity, COA7625, August 17, 2026). Follow the storage stated on the label and certificate. Also offered as a liquid spray.