How Long Does GHK-Cu Take to Work?

The 1988 fibroblast study measured collagen synthesis in cultured cells. It did not examine how long a person would need to use a cream before noticing a visible change. A biochemical response in this model cannot be converted into a week-by-week cosmetic promise. [1]

The 2010 penetration experiment collected measurements over 48 hours using excised human skin. The researchers measured elemental copper after applying a copper-tripeptide preparation; the analysis did not establish whether all measured copper remained bound to intact GHK. This was a penetration-and-retention experiment, not a trial of facial appearance. [2]

The 2015 review summarizes cosmetic studies conducted over defined treatment periods. Such reports deserve acknowledgment, but a change recorded at the end of a study does not establish when it first became visible, whether every participant benefited, or whether a different cream would have the same result. [4]

For comparison of research design only, a controlled retinol study used a 24-week observation period in older adults’ arm skin. That duration belongs to that retinol experiment; it is neither a GHK-Cu timeline nor a general deadline for topical skincare results. [3]

The 2015 review authors list Skin Biology’s Research & Development Department as their affiliation, a relevant commercial skincare connection. They also declare no conflict of interests regarding publication. The review is a secondary summary rather than an independent new trial. [4]