What Is PT-141?

Also known as: Bremelanotide, Vyleesi

PT-141 (bremelanotide) is a melanocortin-4 receptor agonist that treats sexual desire through the nervous system rather than blood flow — a fundamentally different mechanism from Viagra-class drugs. It was discovered as a Melanotan II metabolite when tanning-study participants reported unexpected effects.

It earned FDA approval in 2019 as Vyleesi, an on-demand injection for hypoactive sexual desire disorder in premenopausal women, and is widely used off-label by men — often when PDE5 inhibitors fail or when the issue is desire rather than function.

What is PT-141 studied for?

Side effects & safety

Trial-documented: nausea (the big one — up to 40% at first dose, usually fading), flushing, headache, and transient blood-pressure elevation that warrants caution with cardiovascular disease. Darkening of skin/gums with frequent use reflects its melanocortin ancestry.

Legal & approval status

FDA-approved as Vyleesi for its specific indication; research-market vials sit outside that chain of custody.

Typical dosing at a glance

Commonly reported protocols use 500 mcg–2 mg, as needed, 45min–2h before activity, via subcutaneous injection. For the mixing math — how much bacteriostatic water, exact syringe units, doses per vial — see the PT-141 reconstitution calculator →

Related peptides

What is Melanotan II?What is Kisspeptin-10?What is Gonadorelin?

Educational overview based on published research and commonly reported community protocols — not medical advice, and not an endorsement of any compound. Consult a licensed healthcare provider.