Side by side

1. 1.Activates melanocortin receptors, particularly MC4R, in the hypothalamus.
2. 2.MC4R signalling is involved in sexual arousal pathways, which is how it affects desire rather than blood flow.
3. 3.It acts centrally rather than on blood vessels, which distinguishes it from erectile drugs like sildenafil.
4. 4.Its half-life is a few hours, so a dose is taken on demand rather than daily.
5. 5.Nausea is the most consistent side effect, linked to the same central receptors.

• Hypoactive sexual desire disorder in premenopausal women (approved)
• Erectile dysfunction, studied but not approved
• Female sexual arousal disorder
• Sexual side effects of antidepressant medication

• Increased sexual desire and arousal
• Nausea and flushing after dosing
• Headache
• Transient blood-pressure rise
• No effect on 'tanning' despite the melanocortin link

• Nausea, reported by about 40% of treated patients and strongest after the first dose
• Flushing
• Headache and vomiting
• Injection-site reactions
• A transient rise in blood pressure and fall in heart rate after each dose
• Fatigue, dizziness and tingling, less common
• Darkening of the gums or skin with repeated use

Research context only for anything outside the licensed indication. The approved product Vyleesi is a 1.75 mg subcutaneous autoinjector for premenopausal women with hypoactive sexual desire disorder, used on demand at least 45 minutes before activity, no more than once in 24 hours and no more than eight times a month. Unapproved 'PT-141' sold as a research chemical has not been tested for purity or dose accuracy.

Research context only