PT-141
PT-141 (bremelanotide) is a synthetic melanocortin receptor agonist that acts on MC3R/MC4R in the central nervous system to modulate sexual arousal and desire. Its FDA-approved form, Vyleesi, is indicated only for hypoactive sexual desire disorder (HSDD) in premenopausal women; research-grade PT-141 sold outside this indication is not FDA-approved.
PT-141 reconstitution calculator
Open full calculator →Typical dosing
| Goal | Range | Route | Frequency |
|---|---|---|---|
| HSDD (FDA-approved regimen, Vyleesi) | 1.75 mg fixed dose | SubQ (abdomen or thigh) | As needed, ~45 min before activity; max 1 dose/24 h, max 8/month |
Ranges compiled from research literature — not a prescription.
How it works
Bremelanotide is a cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH) that non-selectively activates melanocortin receptors, with its clinically relevant activity occurring at MC3R and MC4R. Unlike PDE5 inhibitors (e.g., sildenafil), which act peripherally on vascular smooth muscle to increase genital blood flow, bremelanotide acts centrally, within the hypothalamus and limbic structures that govern sexual motivation.
In women, presynaptic MC4R activation is believed to stimulate dopamine release in the nucleus accumbens, medial preoptic area, ventral tegmental area, arcuate nucleus, and amygdala — regions implicated in the motivational and appetitive components of sexual response. Functional neuroimaging work (published in JCI) found that bremelanotide altered brain activity patterns in these circuits in women with HSDD, distinguishing it mechanistically from vascular-acting agents.
The clinical evidence base is the RECONNECT program: two identical 24-week, randomized, double-blind, placebo-controlled phase 3 trials (~1,200 premenopausal women) that met co-primary endpoints — improvement in Female Sexual Function Index desire-domain score and reduction in desire-related distress (both p<0.001 vs placebo) — and this evidence supported FDA approval as Vyleesi in 2019. A 52-week open-label extension reported sustained effects and no new safety signals.
All controlled clinical evidence comes from premenopausal women with a diagnosed HSDD; there is no equivalent FDA-reviewed trial dataset for men. Use in men, or use of research-grade (non-Vyleesi) PT-141 material by anyone, is off-label/unapproved and relies on a much thinner and lower-quality evidence base than the approved indication.
Side effects & safety
- Nausea is the most common adverse effect (~40% in trials), typically strongest with the first dose and improving with subsequent doses; about 8% of trial participants discontinued due to nausea.
- Flushing and headache are also common, generally mild-to-moderate and transient.
- Each dose causes a transient rise in blood pressure (~6 mmHg systolic / 3 mmHg diastolic on average) and a drop in heart rate, usually resolving within 12 hours; Vyleesi is contraindicated in uncontrolled hypertension or known cardiovascular disease.
- Focal hyperpigmentation (skin darkening, especially face/gums/breasts) occurs in roughly 1% of patients with repeated dosing and is not confirmed to resolve in all cases.
- Bremelanotide can significantly reduce systemic exposure of oral naltrexone, so it should not be combined with naltrexone-containing products used for addiction treatment.
- Research-grade PT-141 sold outside the Vyleesi supply chain is not FDA-regulated — purity, dosing accuracy, and sterility are not verified, adding risks beyond those documented in the clinical trials.
Research
Primary sources — PubMed.
- FDA. Vyleesi (bremelanotide) Prescribing Information. 2019. https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/210557s000lbl.pdf
- DailyMed. Vyleesi (bremelanotide injection) label. https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=8c9607a2-5b57-4a59-b159-cf196deebdd9
- Kingsberg SA, et al. Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder (RECONNECT Study 301). PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC6819021/
- Simon JA, et al. Bremelanotide RECONNECT Study 302. PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC6819023/
- Bremelanotide long-term open-label extension safety. PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC9525110/
- Bremelanotide functional neuroimaging in women with HSDD. J Clin Invest. https://www.jci.org/articles/view/152341
- Diamond LE, et al. An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide. J Sex Med. 2006. https://pubmed.ncbi.nlm.nih.gov/16839319/