Compare Melanotan II and GHK-Cu
These entries share an interest in skin. Their experiments, routes and unresolved problems are quite different.
The catalogue entries
| Question | Melanotan II | GHK-Cu |
|---|---|---|
| What is the molecule? | A cyclic heptapeptide modelled on alpha-MSH | A copper-binding tripeptide |
| Main skin target | Pigment-making melanocytes | Matrix-maintaining fibroblasts |
| Human studies discussed here | A pigmentation pilot and an erectile-function crossover study | Small topical skin studies, plus a GHK-containing combination hair trial |
| Route in those studies | Subcutaneous injection | Topical application |
| A defining uncertainty | Serious reported harms and unknown long-term safety | Delivery across the skin barrier and extrapolation beyond topical studies |
The melanocortin history and GHK skin review explain the different mechanisms. I would never combine the study populations into a general verdict about “skin peptides.” Each entry has a different subject.
Assigning the human results
For Melanotan II, the pigmentation pilot involved 3 healthy men, and the erectile-function trial involved 10 men with psychogenic erectile dysfunction. The outcomes were pigmentation and erectile measures. Neither study establishes protection against skin cancer, reliable weight loss or long-term safety.
For GHK-Cu, topical skin findings sit alongside the 45-man combination hair trial. That trial used 5-aminolevulinic acid plus GHK. Calling it evidence that pure GHK-Cu regrows hair would assign a mixture’s result to a different preparation.
I credit the local skin studies; systemic anti-aging remains a much larger, unresolved claim. Melanotan II’s small human experiments show biological activity alongside a safety record that demands attention. These are separate judgements about separate records; ranking the pair as though they were interchangeable treatments would add very little.
Approval, route and risk
Melanotan II has no approved use anywhere and is prohibited in sport under WADA S0. GHK-Cu’s topical cosmetic status concerns a different category from an approved drug. GHK-Cu has no FDA-approved therapeutic indication, including for injectable or systemic use. Individual clinical assessment and applicable compounding rules govern prescription access; compounded medications are not FDA-approved.
Risk also resists a single ranking. Melanotan II has reported serious kidney, muscle, neurological, erectile and melanocytic harms; the renal case review is a useful place to begin. GHK-Cu’s comparatively limited human literature is mainly topical, with formulation, local tolerability and pigmentation concerns. Missing systemic evidence cannot establish systemic safety.
The delivery review is a reminder that route and formulation help determine what an experiment actually tested. The questions page untangles the names that tend to get lost between these entries.