GHK-Cu topical — vehicle matters more than concentration

Saw a study comparing the same GHK-Cu concentration in cream vs serum bases. The penetration profile was 2-3x different. The 'X% GHK-Cu' number on a cosmetic product label is almost useless without the vehicle context.

Reformulating my own research prep with a serum base after seeing the comparative data. The cream-based commercial products are leaving most of the active in the stratum corneum.