Questions about peptide names and claims
The awkward little distinctions are often where a broad claim starts to come apart.
What is Melanotan 2?
Melanotan 2, Melanotan II, MT-2 and MTII name the same synthetic cyclic peptide. It is an analog of alpha-MSH, designed for stronger, more stable melanocortin activity. The historical review follows the development and the related compounds. Melanotan I refers to the separate linear analog afamelanotide. I wish the names made that structural difference easier to remember.
What is Melanotan 2 used for in research?
Human experiments examined pigmentation and erectile function. The food-motivation experiment discussed here used male mice and direct administration into the nucleus accumbens. That last result concerns a particular animal model. Those mice cannot establish a human weight-loss outcome.
Melanotan 2 mechanism of action
Melanotan II activates melanocortin receptors. MC1R activation on pigment cells recruits cAMP, PKA, CREB and MITF, increasing the pigment-making enzyme tyrosinase and favouring eumelanin. This sequence is the melanogenesis signalling cascade. MC4R and MC3R help explain the sexual-function and appetite research, as described in the melanocortin review. Its broad receptor activity also helps explain why the effects reach beyond skin.
GHK versus GHK-Cu
GHK is the free glycine–histidine–lysine tripeptide; GHK-Cu includes bound copper. Copper tripeptide-1 is the cosmetic name for the copper complex. The skin-regeneration review describes copper’s importance to tissue-remodelling activity. A paper about GHK, a modified form or a mixture needs its own entry rather than automatic transfer into the GHK-Cu column.
GHK-Cu skin effects
In cell studies and the literature gathered in the GHK skin review, GHK-Cu affects fibroblast production of collagen and other matrix components, along with matrix-remodelling enzymes and their inhibitors. Small topical human studies report skin changes. Getting the material through the skin is a separate practical problem, explored in the topical delivery review.
GHK-Cu anti-aging claims
“Anti-aging” stretches a long way beyond the local skin outcomes measured in small topical studies. The gene-data review describes gene-expression work; the hair study tests a combination containing GHK. Neither establishes systemic rejuvenation in people. I’m comfortable being interested in the skin findings while remaining sceptical of that much larger promise.
Are these peptides approved drugs?
Melanotan II has no approval for any indication. Afamelanotide and bremelanotide have separate approvals that apply to those compounds. GHK-Cu is a legal topical cosmetic ingredient in the US, EU and UK, with no FDA-approved therapeutic indication. Injectable or systemic GHK-Cu has no FDA approval, including when provided as a compounded prescription medication. The comparison puts the different routes and records together.