PT-141

Melanocortin receptor agonist · Also known as Bremelanotide, Vyleesi

What is pt-141?

An FDA-approved peptide (marketed as Vyleesi) for treating hypoactive sexual desire disorder (HSDD) in premenopausal women. Unlike PDE5 inhibitors that work on blood flow, PT-141 acts directly on the central nervous system to increase sexual desire.

PT-141 was originally developed as a sunless tanning agent derived from Melanotan II, but researchers discovered its potent effects on sexual arousal during clinical trials. In 2019 the FDA approved bremelanotide (Vyleesi) for HSDD in premenopausal women, making it the first injectable treatment for this condition. It works through a fundamentally different mechanism than drugs like sildenafil. rather than enhancing blood flow, it activates melanocortin receptors in the brain to modulate desire and arousal pathways.

Key takeaway: PT-141 is the only FDA-approved injectable for female sexual desire disorder, working through brain-based melanocortin pathways rather than the vascular mechanisms used by erectile dysfunction drugs.

Benefits & evidence

Increased sexual desire (women) High confidence
Improved sexual arousal High confidence
Treatment of HSDD High confidence
Erectile function (men) Moderate confidence
Sexual satisfaction Moderate confidence

How it works

PT-141 is a nonselective melanocortin receptor (MCR) agonist, with highest potency at MC1R and MC4R. The MC4R receptors in the hypothalamus are involved in regulating sexual behavior and arousal. By activating these central nervous system pathways, PT-141 increases sexual desire and arousal independent of peripheral blood flow mechanisms.

The exact mechanism by which PT-141 improves HSDD is not fully characterized, but activation of MC4R in the brain is thought to modulate dopaminergic and oxytocinergic pathways involved in sexual motivation. Because it works centrally rather than peripherally, it is effective for desire-related dysfunction in both men and women, though it is only FDA-approved for women.

Dosing information

Typical dosing protocol
Starting dose

1.75 mg as needed

Single dose, at least 45 min before activity
Maintenance dose

1.75 mg as needed

Ongoing

FDA-approved dose is 1.75 mg subcutaneously. No more than one dose per 24 hours and no more than 8 doses per month. Nausea is common with the first injection and tends to decrease with subsequent use.

Side effects

Most side effects tend to improve as your body adjusts.

Nausea Common
Flushing Common
Injection site reaction Common
Headache Common
Skin hyperpigmentation Uncommon
Transient blood pressure increase Uncommon