What it is
PT-141 (bremelanotide) is a melanocortin receptor agonist. It is FDA-approved, under the brand name Vyleesi, for hypoactive sexual desire disorder (HSDD) in premenopausal women, and it is also used off-label for libido and arousal in both sexes outside that approved indication. Because bremelanotide's approved indication is narrow, most discussion of the compound distinguishes between its FDA-approved use in Vyleesi and the wider off-label interest in it for general libido and arousal.
In the PeptidesAI encyclopedia it is categorized under cognitive, reflecting its studied action through the brain rather than through the body's vascular system. Bremelanotide was originally studied, and in some cases used off-label, under the name PT-141 before its approval as Vyleesi, which is why the compound is commonly referred to by both names.
How it's thought to work
PT-141 is studied for activating central melanocortin receptors, primarily MC4R, in the brain to increase sexual desire and arousal. Research describes this as a central, dopamine-linked pathway, meaning it acts through brain signaling rather than through a vascular (blood-flow) mechanism, which distinguishes it from medicines that work by increasing blood flow directly.
What the research says
PT-141 is FDA-approved as Vyleesi specifically for HSDD in premenopausal women. Broader off-label use in other populations is not FDA-approved, even though the underlying compound is the same.
Reported side effects
The most common reported side effect is nausea, described as the main factor limiting use. Other reported effects include flushing, headache, a transient increase in blood pressure, and, with repeated use, possible skin darkening, a melanocortin-related effect.
Reconstitution
PT-141 (bremelanotide) is supplied as a lyophilized (freeze-dried) powder and is typically reconstituted with bacteriostatic (BAC) water before use. It commonly comes in 10 mg vials. The amount of peptide in the vial is fixed; the water added only changes how concentrated the solution is.
Worked example. A 10 mg vial is 10,000 mcg. Reconstituted with 2 mL of BAC water, that works out to 10,000 mcg ÷ 2 mL = 5,000 mcg/mL. On a U-100 insulin syringe, where each unit is 0.01 mL, each unit holds 5,000 × 0.01 = 50 mcg. Use the peptide reconstitution calculator to work out the concentration and units for any vial size and water volume.
Important notes
PT-141 is FDA-approved only for a specific indication, HSDD in premenopausal women; use outside that approved population is not FDA-approved. It can also transiently raise blood pressure, a relevant caution for anyone with a cardiovascular condition.
Frequently asked questions
These questions cover the same ground as the sections above, in a shorter format.
What is PT-141?
A melanocortin receptor agonist, FDA-approved as Vyleesi for hypoactive sexual desire disorder in premenopausal women.
How is PT-141 thought to work?
It activates central melanocortin receptors, primarily MC4R, in the brain to increase sexual desire and arousal through a dopamine-linked pathway.
What does the research on PT-141 say?
It is FDA-approved as Vyleesi for HSDD in premenopausal women; broader off-label use in other populations is not FDA-approved.
What are the reported side effects of PT-141?
Nausea is most common and dose-limiting; flushing, headache, transient blood pressure increases, and possible skin darkening with repeated use are also reported.
How much is one unit from a 10 mg PT-141 (bremelanotide) vial?
With 2 mL of BAC water, a 10 mg vial is 5,000 mcg/mL, so one unit on a U-100 syringe (0.01 mL) holds 50 mcg.
The full entry, plus the calculator
The PeptidesAI app has the complete encyclopedia entry for PT-141 (bremelanotide) — one of 70 compounds covered — plus the reconstitution calculator, a dose log and reminders. Free to download on iPhone.
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