Reproductive & hormonal
Bremelanotide (PT-141)
The melanocortin peptide approved as Vyleesi for low sexual desire in premenopausal women — an on-demand drug, not a tanning product.
What it is
Bremelanotide, previously known as PT-141, is a synthetic peptide that activates melanocortin receptors in the brain. It is approved in the United States as Vyleesi for hypoactive sexual desire disorder in premenopausal women, where it is used on demand rather than daily. It is not approved for use in men and it is not a tanning agent, despite belonging to the same receptor family as melanotan.
How it works
- 1
Activates melanocortin receptors, particularly MC4R, in the hypothalamus.
- 2
MC4R signalling is involved in sexual arousal pathways, which is how it affects desire rather than blood flow.
- 3
It acts centrally rather than on blood vessels, which distinguishes it from erectile drugs like sildenafil.
- 4
Its half-life is a few hours, so a dose is taken on demand rather than daily.
- 5
Nausea is the most consistent side effect, linked to the same central receptors.
What it's studied for
Reported and studied effects
- Increased sexual desire and arousal
- Nausea and flushing after dosing
- Headache
- Transient blood-pressure rise
- No effect on 'tanning' despite the melanocortin link
Research protocol notes
Research context onlyResearch 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.
These figures are described so you can understand what researchers did. They are not a dose, a schedule, or a suggestion — and they are not a substitute for a doctor.
Possible side effects and contraindications
Safety profile
Possible side effects
- 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
Contraindications and cautions
- Uncontrolled high blood pressure
- Cardiovascular disease
- Pregnancy and breastfeeding
- Not for use with nitrate medication without medical review
A side-effect list is never complete, and these are not the only situations that warrant caution. Anything unexpected, or anything you are unsure about, should be discussed with a doctor before use.
Evidence assessment
Randomised controlled trials supported its approval for hypoactive sexual desire disorder in premenopausal women, making it one of the few peptides on this site with strong human evidence for its licensed use.
References
- 01Bremelanotide trials in hypoactive sexual desire disorder — PubMed search
- 02Bremelanotide (Vyleesi) prescribing information — FDA
- 03Melanocortin receptors and sexual function — PubMed search
References link to published literature, regulator pages or literature indexes. Where a link points to a search, it collects the peer-reviewed work on that molecule rather than a single study.
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