PT-141 vs Melanotan II: Melanocortin Peptide Comparison for Sexual Health Research | Peptpedia
This comprehensive analysis compares PT-141 and Melanotan II based on peer-reviewed clinical research, examining their mechanisms of action, efficacy data, and safety profiles. For complete individual peptide profiles, visit the dedicated research pages linked above.
PT-141 (Bremelanotide) and Melanotan II are both cyclic heptapeptide analogs of alpha-MSH acting on melanocortin receptors, but with different selectivity profiles and regulatory status. PT-141 received FDA approval in 2019 (as Vyleesi) for hypoactive sexual desire disorder in premenopausal women—the only melanocortin peptide with this approval. Melanotan II has broader melanocortin receptor activation including MC1R (tanning) and more pronounced side effects.
Chemical Identity
Side-by-Side Comparison
| Property | PT-141 | Melanotan II |
|---|---|---|
| Structure | Cyclic 7-AA lactam (modified alpha-MSH) | Cyclic 7-AA (alpha-MSH analog) |
| Primary Receptors | MC3R, MC4R (central) | MC1R, MC3R, MC4R, MC5R (broader) |
| FDA Status | Approved: Vyleesi (2019, HSDD) | Not approved; no clinical trials |
| Tanning Effect | Minimal (poor MC1R affinity) | Significant (strong MC1R activation) |
| Sexual Function | Primary indication | Observed; not studied in RCTs |
| Administration | Subcutaneous auto-injector | Subcutaneous injection (research) |
| Nausea Risk | Moderate (40% in trials) | Higher (strong MC3R/MC4R activation) |
Regulatory Landscape: FDA Approval and Status
PT-141 (Bremelanotide) completed the full drug development pathway. After initial development as a potential tanning agent and a Phase 3 program for sexual dysfunction, the FDA approved Bremelanotide (Vyleesi) in June 2019 specifically for hypoactive sexual desire disorder (HSDD) in premenopausal women. This makes it the second FDA-approved treatment for HSDD (after flibanserin/Addyi). The approved product is an auto-injector for subcutaneous administration as needed, not more than once per 24 hours.
Melanotan II has never been evaluated in formal human clinical trials and has no regulatory approval in any country. It has been available through research chemical suppliers and has been widely self-administered, generating a substantial body of anecdotal and observational data but no controlled safety or efficacy evidence.
Frequently Asked Questions
Research Citations
Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial
Clayton AH, Althof SE, Kingsberg S, et al. (2016). Women's Health