GHK — questions, answered plainly.

GHK is the tripeptide Gly-His-Lys — the uncomplexed form of GHK-Cu. It is endogenously present in human plasma and declines significantly with age. Most published mechanism research uses the copper-bound form (GHK-Cu).

Same tripeptide sequence. GHK is uncomplexed; GHK-Cu is the same peptide bound to a Cu(II) ion. Because GHK binds copper avidly in solution, the two forms are largely interconvertible in biological contexts — the copper-bound form is the more characterised pharmacological entity.

Yes — published research documents an age-related decline in plasma GHK levels, which is part of the framing in the Dou 2020 review (PMID 35083444). The Pickart 2015 review (PMID 26236730) frames GHK's broad cellular-pathway effects.

The Mortazavi 2024 BioImpacts review (PMID 39963574) frames GHK-Cu and palmitoylated GHK derivatives in topical anti-wrinkle research, noting that cosmetic-market availability outpaces robust controlled clinical-trial evidence.

No. GHK is not approved as a medicine in any jurisdiction. Topical / cosmetic formulations exist commercially but are regulated as cosmetics, not as medicines, in most regions.

Standalone uncomplexed-GHK research is narrower than GHK-Cu research because the two forms interconvert in solution. Cosmetic-market availability is not equivalent to controlled clinical evidence.