Mechanism: Melanocortin
PT-141 vs Melanotan II: Melanocortin Receptor Comparison
Both act on melanocortin receptors and influence sexual arousal. PT-141 is FDA approved for female hypoactive sexual desire. Melanotan II has libido effects as a side property of MC1R and MC4R agonism for pigmentation.
Side-by-side comparison
| Attribute | PT-141 (Bremelanotide) | Melanotan II |
|---|---|---|
| Receptor selectivity | MC4R selective | Pan melanocortin agonist |
| Approved indication | Female HSDD, 1.75 mg as needed | None |
| Primary effect | Sexual arousal | Pigmentation, libido secondary |
| Side effects | Nausea, flushing, transient BP rise | Pigmentation, mole darkening, nausea, priapism risk |
| Typical research dose | 1 to 2 mg subcutaneous as needed | 250 to 500 mcg daily titration |
Key differences
- ·PT-141 is MC4R selective with cleaner libido focus
- ·Melanotan II hits MC1R, MC3R, MC4R, MC5R causing pigmentation and other effects
- ·PT-141 is approved at 1.75 mg, Melanotan II is unapproved
- ·Melanotan II commonly causes nausea, flushing, and skin darkening
Research summary
Kingsberg et al. (2019) phase 3 data established bremelanotide efficacy for HSDD. Melanotan II libido effects are documented but were not the development target, and the pigmentation side effects limit its use as a libido agent.