Comparison
Two products from the same melanocortin research lineage, sold for completely different purposes.
PT-141 is bremelanotide, the refined MC4R-selective descendant that became an approved drug for hypoactive sexual desire; melanotan-2 is the unapproved parent peptide whose side effects revealed that pathway in the first place.
Bremelanotide was developed from the melanotan research program after libido effects kept appearing in tanning-peptide studies. Melanotan-2 is the broader, less selective parent; PT-141 is the purpose-built descendant for the sexual-health effect.
PT-141 (as Vyleesi) is FDA-approved for hypoactive sexual desire disorder in premenopausal women, with a labeled as-needed schedule. Melanotan-2 is unapproved everywhere and has drawn regulator warnings for years.
Both hit melanocortin-4 receptors, which is why nausea, flushing, and blood-pressure effects show up in both. PT-141's development was largely an exercise in keeping the MC4R effect while leaving the tanning behind.
| Dimension | Melanotan-2 | PT-141 |
|---|---|---|
| Overall evidence grade | D | A |
| Evidence label | Limited human evidence | Strong human evidence |
| Regulatory status | Not FDA-approved for listed uses | Approved for specific use |
| Editorial confidence | Moderate confidence | High confidence |
| Efficacy | 1/5 limited | 4/5 substantial |
| Safety | 1/5 limited | 3/5 emerging |
| Regulatory risk | 5/5 very high | 1/5 low |
| Product quality risk | 5/5 very high | 3/5 moderate |
| Primary claim categories | Unapproved tanning-product context, Melanocortin receptor pathway, Gray-market product-quality risk, Skin and pigmentary safety concerns, Libido and performance claim context | Approved HSDD context, Melanocortin receptor pathway, Sexual desire and distress endpoints, Safety and tolerability warnings, Performance and gray-market claims |
Melanotan-2 is not an FDA-approved tanning product. Regulators tie it to unregulated tanning-market promotion, and approved melanocortin drug labels do not transfer to it.
PT-141 is best understood through the approved Vyleesi HSDD evidence, not generic libido, male performance, tanning, melanotan, or gray-market peptide claims.
FDA. Notice of Opportunity for Hearing (NOOH) Manookian, Edward 8/5/16 2016.
Accessed 2026-06-09.
FDA enforcement source describing Melanotan II as an unapproved new drug marketed as an injectable tanning product; used only for regulatory-risk and claim-boundary framing.
Other. Don't risk using tanning products containing melanotan 2025.
Accessed 2026-06-09.
Australian TGA warning source for melanotan I/II tanning products, online promotion, unapproved-product quality risk, adverse-event concerns, and advertising restrictions.