PT-141 (Bremelanotide)

Also known as: Vyleesi, bremelanotide

A melanocortin peptide that cleared trials and won approval — for one specific condition, not general 'libido enhancement'.

Melanocortin peptidesEvidence for fitness claims:Well-supported· human data

Regulatory status: FDA-approved (as Vyleesi) for hypoactive sexual desire disorder (HSDD) in premenopausal women.

What it is

PT-141 (bremelanotide) is a melanocortin-receptor agonist — a peptide that acts on brain pathways involved in sexual desire. It matters as a reference because, like tesamorelin, it went through proper trials and won approval — for one specific condition.

Composition

It is a synthetic cyclic peptide derived from alpha-melanocyte-stimulating hormone (alpha-MSH). It is a close relative of Melanotan II, but developed and studied as a medicine rather than sold as a tanning chemical.

Proposed mechanism

It activates melanocortin receptors in the brain — principally MC4R in the hypothalamus and limbic system — which are part of the neural circuitry of sexual desire. This is a central (brain) mechanism, distinct from erectile-function drugs that work on blood flow.

Claimed benefits

Increased libido and sexual arousal, promoted broadly for “sexual wellness” in both sexes. The approved evidence is narrower than the marketing.

What the evidence shows

Well-supported· human data — for its approved indication. Two large Phase 3 randomised placebo-controlled trials (the RECONNECT studies, over 1,200 women; Kingsberg et al., 2019) showed statistically significant improvements in sexual desire and reduced distress in premenopausal women with hypoactive sexual desire disorder (HSDD). Evidence outside that group — in men, or for general “enhancement” — is far weaker.

Legal & regulatory status

FDA-approved (as Vyleesi) for HSDD in premenopausal women — prescription only, for that use. Grey-market PT-141 is unlicensed. It is not currently on the WADA prohibited list, but the licensed product carries specific warnings that grey-market use ignores.

Known risks & unknowns

In trials, nausea, flushing and headache were common. It can transiently raise blood pressure and is contraindicated in uncontrolled hypertension or known cardiovascular disease; repeated use can darken skin and moles (a melanocortin effect). Unlicensed versions add purity and dosing unknowns on top of these characterised risks.

Sources

Frequently asked questions

What is PT-141 approved for?

As Vyleesi, bremelanotide is FDA-approved for hypoactive sexual desire disorder (HSDD) in premenopausal women, based on two large Phase 3 trials (the RECONNECT studies). Uses beyond that — including in men, or for general 'libido enhancement' — are outside the approved indication.

How does it work?

It is a synthetic melanocortin-receptor agonist, structurally related to alpha-MSH. It acts on melanocortin receptors (notably MC4R) in the brain, which are involved in the neural circuitry of sexual desire — a different mechanism from erectile-function drugs that act on blood flow.

Is grey-market PT-141 the same as Vyleesi?

The molecule may be nominally the same, but a 'research chemical' vial is not a quality-controlled medicine. Purity, dose and sterility cannot be assumed, and the approved product comes with a specific label, warnings and dosing that grey-market use ignores.

What are the known side effects?

In the trials, nausea, flushing and headache were common, and transient blood-pressure increases and (with repeated use) skin darkening were noted. It is contraindicated in uncontrolled high blood pressure or known cardiovascular disease.