PT-141 (Bremelanotide)

What it is

PT-141 (bremelanotide) is a synthetic cyclic heptapeptide and an agonist at melanocortin receptors, particularly MC3R and MC4R in the central nervous system. It was derived from Melanotan II, an earlier melanocortin peptide studied for tanning and sexual function. Unlike the GLP-1 agonists, which act peripherally, bremelanotide acts primarily in the brain on pathways involved in sexual desire. It is marketed as Vyleesi for the FDA-approved prescription indication.

What researchers study it for

• Hypoactive sexual desire disorder (HSDD) in premenopausal women This is the approved indication. The Phase 3 RECONNECT trials enrolled premenopausal women diagnosed with HSDD and found statistically significant improvements in satisfying sexual events and self-reported desire scores compared to placebo over 24 weeks of on-demand use. [1]
• On-demand dosing profile Unlike flibanserin (Addyi), which requires daily oral dosing, bremelanotide is taken on-demand approximately 45 minutes before anticipated sexual activity. Researchers and clinicians have studied whether this profile offers practical advantages for adherence and side effect management in women with HSDD. [4]
• Long-term safety and tolerability The RECONNECT extension study followed participants for 52 weeks and found that bremelanotide maintained efficacy signals with a consistent adverse event profile. Nausea was reported as transient and most participants who used the drug at least once continued treatment. [2]
• Patient-reported outcomes and treatment satisfaction Exit survey data from RECONNECT participants found that most women who completed the trial reported satisfaction with treatment and indicated they would continue use. Among those who discontinued, adverse effects (primarily nausea and flushing) were cited more often than lack of efficacy. [6]
• Melanocortin receptor mechanism in sexual function Researchers have studied how MC4R agonism in the hypothalamus and other brain regions modulates the neural pathways involved in sexual arousal and desire. This work extends beyond bremelanotide itself to the broader question of central nervous system targets for female sexual dysfunction. [3]

Research context

The evidence base for PT-141 is among the strongest of any peptide on this site: two Phase 3 randomized controlled trials (the RECONNECT studies) were the basis for FDA approval in 2019, and the long-term safety data extends to 52 weeks. [1] [2] The approval was specifically for premenopausal women with generalized, acquired HSDD. The drug has not been approved for men or for postmenopausal women.

It is worth noting that the effect sizes in the RECONNECT trials, while statistically significant, were modest. A 2024 critical reanalysis concluded that the magnitude of improvement in satisfying sexual events and desire scores was small relative to placebo, and that the clinical meaningfulness of the FDA's chosen outcome measures remains contested in the research literature. [5] Researchers and patients should weigh the statistical significance of the trial results against the practical magnitude of benefit and the frequency of adverse effects, particularly nausea (reported by approximately 40% of participants in the pivotal trials).

Typical research parameters

References

1. [1] Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstetrics and gynecology. 2019;134. PubMed ↗
2. [2] Simon JA, Kingsberg SA, Portman D, et al. Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder. Obstetrics and gynecology. 2019;134. PubMed ↗
3. [3] Dhillon S, Keam SJ. Bremelanotide: First Approval. Drugs. 2019;79. PubMed ↗
4. [4] Edinoff AN, Sanders NM, Lewis KB, et al. Bremelanotide for Treatment of Female Hypoactive Sexual Desire. Neurology international. 2022;14. PubMed ↗
5. [5] Spielmans GI, Ellefson EM. Small Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder. Journal of sex research. 2024;61. PubMed ↗
6. [6] Koochaki P, Revicki D, Wilson H, et al. The Patient Experience of Premenopausal Women Treated with Bremelanotide for Hypoactive Sexual Desire Disorder: RECONNECT Exit Study Results. Journal of women's health (2002). 2021;30. PubMed ↗

Related research notes