Sexual function

PT-141

Also known as: Bremelanotide, Vyleesi, PT141

PT-141 is the only peptide on this list approved by the FDA specifically for sexual function — and the only one whose pivotal Phase III evidence (RECONNECT, n=1,267) is in women, while the dominant biohacker conversation is about off-label male use.

Routes: Subcutaneous, Intranasal
Half-life: Approximately 2.7 hours plasma half-life on subcutaneous administration; the FDA-labeled use is as-needed dosing approximately 45 minutes before sexual activity, not chronic daily dosing.
Legal status: Prescription only

01·Mechanism

PT-141, marketed as bremelanotide and approved as Vyleesi, is a cyclic heptapeptide melanocortin receptor agonist developed from the α-melanocyte-stimulating hormone (α-MSH) family. It is a non-selective melanocortin agonist with activity at MC1, MC3, MC4, and MC5 receptors; the MC4 receptor activity, particularly in the central nervous system, is the principal mechanism for sexual-desire and arousal effects. Unlike PDE5 inhibitors (sildenafil, tadalafil), which act peripherally on the vasculature of erectile tissue, PT-141 acts centrally — in the hypothalamic and other CNS pathways that regulate sexual desire and arousal — making the mechanism more upstream and the experiential profile distinct. The cyclic structure was engineered for stability against enzymatic degradation, supporting the as-needed subcutaneous dosing profile of the FDA-approved formulation ([Kingsberg et al., *Obstet Gynecol* 2019, 134:899–908](https://doi.org/10.1097/AOG.0000000000003500)).

02·Overview

PT-141 is the only peptide on this site approved by the FDA specifically for sexual function. The pivotal RECONNECT trials (Kingsberg et al., *Obstetrics & Gynecology* 2019) randomized 1,267 premenopausal women with acquired generalized hypoactive sexual desire disorder (HSDD) across two parallel Phase III studies of subcutaneous bremelanotide 1.75 mg as-needed versus placebo. Both trials met co-primary endpoints — bremelanotide produced statistically significant increases in sexual desire and statistically significant reductions in associated distress as measured by validated patient-reported instruments. The FDA approval (June 2019) and Vyleesi labeling are based on this evidence. The labeled indication is narrow: premenopausal women with acquired generalized HSDD, on-demand dosing approximately 45 minutes before anticipated sexual activity, with a maximum of one dose per 24 hours and eight doses per month. The off-label and biohacker conversation has expanded well beyond this indication. The dominant non-labeled use is in men for erectile function, libido enhancement, and as a complement or alternative to PDE5 inhibitors. There is published academic evidence supporting PT-141's effect on sexual function in men — early-development trials of intranasal bremelanotide showed activity in men with erectile dysfunction, and the molecule's central-mechanism profile is mechanistically attractive for libido-related rather than purely peripheral-vascular indications. But the pivotal Phase III evidence supporting current FDA approval is in women, and the safety and efficacy profile in male off-label use rests on smaller and more variable datasets. The honest framing has two parts. First, PT-141 has more rigorous pivotal-trial evidence behind its approved indication than most peptides on this site combined; that part of the story is solid. Second, the dominant practitioner conversation about PT-141 is largely about off-label use that is not what the pivotal trials studied, and the gap between the regulatory evidence base and the practitioner application is wider for PT-141 than for any FDA-approved peptide on this list. The peptide that is approved is studied; the peptide that is most often used is approached partly through inference.

03·1 primary source

Each entry below is graded on the four-tier evidence scale (peer-primary → practitioner) and carries an independent strength label that captures how robustly the source supports the claim it backs on this page.

Tier 1 · Peer primarystrong
Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials
Kingsberg SA, Clayton AH, Portman D, et al. · 2019 · Obstetrics and Gynecology

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04·Safety

The most commonly reported adverse events in the RECONNECT trials were nausea (~40% on bremelanotide vs. 1.3% placebo), flushing (~20%), and headache. Most were mild-to-moderate and concentrated in the first few doses. Transient hyperpigmentation has been reported with chronic or high-frequency dosing — the melanocortin receptors are expressed on melanocytes and pigmentation effects are mechanism-derived. A modest, transient blood-pressure increase peaks within hours of dosing and returns toward baseline by ~6 hours; the FDA label cautions against use in uncontrolled hypertension and recommends caution in cardiovascular disease. The labeled dosing limit (one dose per 24 hours, eight per month) is part of the safety frame — chronic daily dosing is not how the molecule was studied or approved.

Contraindications

- Uncontrolled hypertension or known cardiovascular disease without specialist oversight (transient blood-pressure increase is a class effect) - History of melanoma or other significant pigmented-lesion concerns (melanocortin agonism in MC1-receptor-expressing tissue) - Pregnancy or breastfeeding (no adequate human safety data; the FDA label contraindicates use in pregnancy) - Concurrent use of medications with significant blood-pressure or vasoactive effects without specialist oversight - Patients under 18 (the trials and approval are in adults) - Use exceeding labeled limits (more than one dose per 24 hours, more than eight per month) is unstudied at the population scale