Head to head
Bremelanotide vs Melanotan II
One terminal group apart, and a world of regulatory difference.
Bremelanotide and melanotan II are near-identical cyclic melanocortin agonists; they differ by a C-terminal acid versus amide. One became an FDA-approved drug for low sexual desire with a label that documents its risks. The other stayed a grey-market tanning peptide with case reports of serious harm.
| Measure | BremelanotideMelanocortin receptor agonist | Melanotan IIMelanocortin receptor agonist |
|---|---|---|
| Best evidence | Established | Clinical |
| Human-tested claims | 2 of 2 | 2 of 2 |
| Status | Approved | Research-only |
| Cited sources | 1 | 2 |
Where the evidence lands
This pair shows what a development program buys. Bremelanotide's side effects are known in frequency and kind, because two Phase 3 trials measured them. Melanotan II's are known from case reports of rhabdomyolysis, priapism and changing moles, which tell you the harms exist but not how often. Structural similarity does not transfer a safety record.
Where they differ
Each row cites a fixed record. Numbers from different trials are not directly comparable, and the rows say so where that applies.
| Aspect | Bremelanotide | Melanotan II |
|---|---|---|
| Structure[1] | Cyclic heptapeptide ending in a free acid. | The same cyclic heptapeptide ending in an amide. |
| Receptor profile[2] | Non-selective, but the therapeutic effect is attributed to central MC4R/MC3R. | Broad MC1R/MC3R/MC4R agonist, which is why it tans as well as arouses. |
| Status[1] | FDA-approved (Vyleesi, 2019) for HSDD in premenopausal women. | No approved use in any jurisdiction. |
| Known safety[3] | Transient blood-pressure rise, nausea, focal hyperpigmentation; not for uncontrolled hypertension. | Case reports of rhabdomyolysis with renal dysfunction, priapism, and darkening or atypia of moles. |
What each is studied for
The efficacy claims from each monograph, with their tiers. Follow the entry for sources and safety.
Bremelanotide
- EstablishedFDA-approved for HSDD in premenopausal women, based on two Phase 3 trials (RECONNECT).
- EstablishedActs centrally as a melanocortin (MC4R/MC3R) agonist rather than on vascular blood flow.
Melanotan II
- ClinicalA broad-spectrum α-MSH analog and potent agonist at MC1R/MC3R/MC4R, driving pigmentation and sexual response (early human Phase I).
- ClinicalSystemic toxicity including rhabdomyolysis and renal dysfunction has been reported after injection.
Frequently asked
Can melanotan II be used for the same purpose as bremelanotide?
It acts on the same receptors and early Phase I work recorded sexual effects, which is how bremelanotide was discovered. But it was never developed, so there is no dose-response, frequency or long-term data, and what is sold under the name is unverified.
References
The monographs
- BremelanotideEstablished
Melanocortin receptor agonist
The FDA-approved libido peptide that skips the vascular route.
2 of 2 claims human-tested · 1 reference · FDA-approved
- Melanotan IIClinical
Melanocortin receptor agonist
The tanning-and-libido peptide that never made it to approval.
2 of 2 claims human-tested · 2 references · Research-only
Written by Twenty Residues editorial. Medical review: pending; a named reviewer is being assigned.
Last updated October 1, 2026.
Tiers are explained in the Standard. Spot an error? Report a correction.