PT-141 (Bremelanotide)
A melanocortin receptor agonist and metabolite of Melanotan II, developed specifically for sexual dysfunction. Under the name bremelanotide (Vyleesi) it is FDA-approved for hypoactive sexual desire disorder (HSDD) in premenopausal women, giving it real randomised-controlled-trial evidence that most peptides on this site lack. Common side effects are nausea, flushing and transient blood-pressure elevation.
01 Overview
PT-141 (bremelanotide) is a cyclic peptide derived from Melanotan II but with the tanning (MC1R) activity minimised, leaving the central pro-sexual (MC4R) effect. Unlike almost every other peptide sold in this space, it completed phase III trials and was approved by the FDA in 2019 as Vyleesi for acquired, generalised HSDD in premenopausal women, administered as a subcutaneous auto-injector before anticipated sexual activity.
Evidence is genuine but modest in effect size: the pivotal trials showed statistically significant but small improvements in desire and reduced distress versus placebo. It is also used off-label by men for erectile dysfunction and libido. The main tolerability issues are nausea, flushing and a transient rise in blood pressure with a compensatory fall in heart rate; it is contraindicated in uncontrolled hypertension or cardiovascular disease.
02 Mechanism
Activates central melanocortin receptors, chiefly MC4R in the hypothalamus, modulating neural pathways involved in sexual desire and arousal. It acts on the central nervous system rather than the vasculature, distinguishing it from PDE5 inhibitors.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Off-label anecdotal | 1–2 mg | SubQ | Range used off-label by men; not a licensed indication. |
| Approved (Vyleesi) | 1.75 mg | SubQ | FDA-approved dose: 1.75 mg subcutaneously at least 45 minutes before sexual activity; no more than one dose per 24 h and eight per month. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Increased sexual desireImproved desire and reduced distress in premenopausal women with HSDD in phase III trials. | Small but significant vs placebo | Clinical | |
| Improved erectile function / libido (off-label)Erectogenic effect demonstrated in earlier trials; used off-label by men. | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| NauseaNausea is the most common adverse effect, sometimes requiring antiemetics and occasionally leading to discontinuation. | Moderate | ~40% in trials | Clinical | |
| Transient blood-pressure rise / heart-rate fallEach dose transiently raises blood pressure (~6 mmHg systolic) and lowers heart rate for several hours. | Moderate | Common, transient | Clinical | |
| Focal hyperpigmentationDarkened patches on the face, gums or breasts with repeated dosing, more common in those with darker skin. | Mild | ~1 in 5 with repeated use | Clinical |
06 Commonly used with
What pt-141 is combined with, and why. This is about intent rather than safety — the interactions table below covers what is dangerous. Nothing here is listed without what it costs.
| Compound | Frequency | Purpose & trade-off |
|---|---|---|
| Support & ancillaries | ||
| Sildenafil or tadalafilPDE5 inhibitor | PT-141 acts centrally on desire while PDE5 inhibitors act peripherally on erectile blood flow, so they are combined to cover both arousal and mechanical function.Trade-off: Both can lower blood pressure, so stacking them raises the risk of hypotension, dizziness and fainting — a combination that is dangerous with nitrates. | |
| Ondansetron or anti-nausea measuresas-needed | Nausea and flushing are the most common PT-141 side effects, so an antiemetic or careful dose timing is used to make it tolerable.Trade-off: It adds another drug for a side effect that is often dose-driven, and antiemetics carry their own effects (headache, constipation) for a symptomatic patch rather than a fix. | |
| TestosteroneTRT | In men with low libido from hypogonadism, TRT addresses the hormonal baseline while PT-141 is used situationally for on-demand desire.Trade-off: TRT is a long-term commitment with suppression, hematocrit and fertility consequences, and if low testosterone is not actually the cause it adds risk without solving the problem. | |