Source comparison
MC1R Selectivity vs Broad Melanocortin Activity
Think of the melanocortin system as a panel of light switches. Melanotan 1 flips one switch, MC1R, which controls pigment. Melanotan 2 flips the whole panel at once. MC1R drives melanin production. MC3R and MC4R sit in the brain and influence appetite and sexu
This comparison does not assign a generated winner or score.
- Think of the melanocortin system as a panel of light switches. Melanotan 1 flips one switch, MC1R, which controls pigment. Melanotan 2 flips the whole panel at once.
- MC1R drives melanin production. MC3R and MC4R sit in the brain and influence appetite and sexual function. MC5R affects exocrine glands. Afamelanotide stays narrow on MC1R, so its action is mostly limited to pigment, which is consistent with its clean trial-grade safety profile (chronic MC1R activation review, PMC11664455).
- Melanotan 2 reaches all four. That broad activation is why it darkens skin and also drives nausea, appetite loss, and erections. The side-effect gap between the two is not random. It maps directly onto how many switches each peptide touches.