GHK-Cu is a copper peptide. Melanotan I is a melanocortin receptor agonist.
They are aimed at different things: GHK-Cu at skin & repair; Melanotan I at tanning & skin protection.
| Comparison | GHK-Cu copper peptide · copper tripeptide-1 | Melanotan I (Afamelanotide) afamelanotide · Scenesse |
|---|---|---|
| How it works | How it works GHK-Cu is three amino acids bound to a copper atom. Your body makes it, levels fall sharply with age, and the copper is doing much of the work. | How it works Melanotan I copies alpha-MSH, the hormone that tells skin to make pigment. It is the only compound in this pair that is an approved medicine. |
| What it is | A copper skincare peptide for smoother, firmer, younger-looking skin. | The safer, approved tanning peptide for a slow, protective tan. |
| Status | Sold over the counterCosmetic ingredient | FDA approvedFDA-approved (Scenesse) |
| Typical dose | — | 0.5–1 mg per day |
| How often | Daily | Daily then weekly |
| Dose comes from | No established range | Community practice |
| Cycled? | Not cycled Community practice | The approved implant is one every 2 months, about 3 a year FDA drug label |
| What it does | ||
| Drug class | Copper peptide | Melanocortin agonist |
| Used for | A skincare peptide used to smooth fine lines, fade dark spots, firm skin, and speed wound healing by boosting collagen. It is basically anti-aging for your skin. | The safer, approved tanning peptide. It builds a slow, even, protective tan and shifts skin toward real sun defense. It has fewer side effects than its cousin, but is slower and pricier. |
| Receptors hit | — | — |
| Numbers | ||
| Full dose line | Topical serum, 1-2 pumps | 0.5 up to 1 mg per day (loading phase) |
| Why that cycle | Used daily as part of a routine. The effect depends on continued use and returns to baseline when you stop, so there is nothing to cycle off. | The approved product is an implant placed every two months, typically three times a year to cover spring and summer. That interval is on the label. The injectable version sold separately is a different product used on a loading-then-maintenance pattern that comes from community practice. |
| Weight / effect | Not measured in a trial | Not measured in a trial |
| Chain length | 3 residues | 13 residues |
| Common vial | 50 mg | 10 mg |
| Before you start | ||
| Route | On the skin (also injectable, off-label) | Under the skin (or implant) |
| Do not use if | A known copper allergy or metal sensitivity, so patch test first Broken or actively irritated skin Layering with strong acids or retinoids on the same area | Pregnancy Approved only for a specific rare light-sensitivity disorder |
What separates them
Proof behind the dose. Every dose here comes from community practice. Not one is backed by a published human study, which is worth knowing before you read the numbers as if they were equivalent.
Staying on it. GHK-Cu is taken continuously. Melanotan I is normally run in blocks with breaks, though for this one the block length is convention rather than a tested schedule.
What doesn't differ: Neither has a measured effect size from a published trial, so there is no number to rank them on.
What people actually report
GHK-Cu
- Very well tolerated on the skin.
- Injecting it has little safety data.
- A spreading rash or significant swelling where applied
Melanotan I (Afamelanotide)
- A cleaner profile than Melanotan II, but you should still watch moles for changes.
- A mole that changes in size, shape, or colour
- Signs of an allergic reaction
Side effects are what users and trials report most often, not a complete list. Anything sudden, spreading, or breathing-related is an emergency regardless of which compound caused it.
People also compare
This comparison does not cover cost, long-term safety, or how you personally will respond. Effect figures come from separate trials in different populations and are not always directly comparable to each other. Nothing here is medical advice or a recommendation to use any of these. Talk to a clinician about your own situation.