PT-141
Melanocortin receptor agonist - the only FDA-approved peptide for sexual arousal, marketed as Vyleesi.
7 residues· First described 1999
Acetyl-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-OH; cyclized melanocortin agonist
Overview
PT-141 (bremelanotide) is a melanocortin-4 receptor agonist originally developed as a tanning agent before its pro-sexual effects were noticed. It's FDA-approved as Vyleesi for premenopausal hypoactive sexual desire disorder in women and is used widely off-label for both sexes as an on-demand libido and arousal peptide.
Unlike PDE5 inhibitors (Viagra, Cialis), PT-141 works centrally on arousal circuits in the brain rather than on peripheral vascular mechanics. This makes it useful when the issue is desire rather than erectile mechanics, and it can work in situations where Viagra doesn't.
It's a short-cycle, on-demand compound rather than a continuous protocol. Track BP (mild transient elevation common), nausea tolerance, and self-reported efficacy.
Mechanism of Action
PT-141 activates the melanocortin-4 receptor (MC4R) in the hypothalamus, stimulating central pro-sexual signaling independent of vascular effects. Downstream it increases dopamine release in the medial preoptic area, which is the classical arousal circuit.
Community Usage Patterns
1–2 mg SC injected 45–90 minutes before anticipated sexual activity. Effects last 2–8 hours. Common side effects: flushing, transient BP elevation, nausea (dose-dependent). Not for daily use - spacing ≥3 days apart is typical. Start at 0.5–1 mg to assess tolerance.
Education only - not medical advice. Any protocol change should involve your licensed provider.
Biomarkers to Track
When running PT-141, these are the biomarkers most commonly tracked to assess response and safety:
Reconstitution Calculator
Free calculator for PT-141 reconstitution math - vial size, BAC water volume, and exact syringe units.
Open PT-141 calculator →Side Effects & Monitoring
What PT-141 side effects are commonly reported, when they appear, the red flags worth a provider call, and the biomarkers that catch issues early.
PT-141 side effects & what to track →Results & What to Track
What PT-141 results actually look like in the data - the markers to measure, when they tend to move, and how to tell a real result from placebo.
PT-141 results & how to measure them →Related Reading
Stacks That Include PT-141
PT-141 Head-to-Head Comparisons
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Start tracking →This page is informational and does not constitute medical advice. MyProtocolStack is a tracking and education platform. Work with a licensed provider before starting, changing, or stopping any protocol.