Skin and appearance
Copper peptides have fifty years of dermatology behind them. The tanning compounds have no approval anywhere.
Covered here: GHK-Cu · Melanotan II
Melanotan II is a synthetic analogue of alpha-melanocyte-stimulating hormone, the hormone that signals pigment cells to produce melanin. It works at melanocortin receptors, which is why it is marketed as a tanning compound, and it has no FDA approval for any use, meaning no agency has reviewed a safety dossier for it. Those receptors are not confined to skin, and nothing sold as research material under that name has a published human safety record.
GHK-Cu is the opposite case, and it is the reason this group holds the strongest evidence covered on this site. GHK is a three-amino-acid sequence, glycyl-histidyl-lysine, found naturally in human plasma, and GHK-Cu is that tripeptide bound to copper. Copper peptides have roughly fifty years of dermatology and wound-healing research behind them, which is unusual in this field, and the firmest findings sit in the least glamorous place: topical work on skin structure, not systemic rejuvenation.
Hair is where the questions outrun the literature. No peptide has a published human efficacy record for hair growth comparable to what exists behind the approved hair drugs, and the copper-peptide work does not transfer across: skin and follicle are different tissues with different endpoints. Our skin review states where the dermatology evidence is strong, where it stops, and what the copper itself may be doing.
Common questions
What is Melanotan II?
Melanotan II is a synthetic analogue of alpha-melanocyte-stimulating hormone that acts at melanocortin receptors, including the receptor involved in melanin production. It is not approved by the FDA or by any comparable regulator for any indication, so no agency has evaluated a safety or efficacy dossier for it.
Are tanning peptides safe?
There is no approved tanning peptide, which means there is no reviewed safety file to point to. The melanocortin receptors these compounds act on are distributed well beyond skin, so the pharmacology is not confined to pigmentation. For material sold in research channels there is no published human safety dataset at all, and that is a gap in the record rather than a reassurance.
What is GHK-Cu, and what are copper peptides?
GHK is a naturally occurring tripeptide, glycyl-histidyl-lysine, present in human plasma. GHK-Cu is that peptide complexed with copper, and copper peptides as a category refers to GHK-Cu and related copper-binding sequences. The category has an unusually long research history for this field, roughly five decades, concentrated in dermatology and wound healing.
What does the research on copper peptides actually report?
The published dermatology literature on GHK-Cu reports effects on skin structure and on wound-healing processes, with the most consistent findings coming from topical application rather than systemic use. It is the best-evidenced group discussed on this site, and that is a statement about the comparison, not a claim of a guaranteed result. Our skin review sets out both what the studies found and where they stop.
Which peptides have the best evidence for skin?
Copper peptides, GHK-Cu in particular, have the longest and most consistent published record of any compound group covered here, and that record is strongest for topical use and for structural endpoints in skin. The further a claim travels from topical skin structure, toward systemic anti-aging or toward hair, the thinner the supporting literature gets.
Are peptides good for hair growth?
No peptide has a published human efficacy record for hair growth comparable to the trial evidence behind the approved hair drugs. The copper-peptide literature is about skin, and findings in skin do not transfer to follicles, which are a different tissue measured against different endpoints. Claims in this area generally rest on mechanism and on marketing rather than on clinical results.
Read the evidence
2 pieces on this subject, every finding attributed and every gap stated.
Related topics
For research use only · Not for human or veterinary use · No compound discussed here is FDA-approved for any indication