It actually targets TRPV1 in the skin, which is a receptor in the skin, but it's also in a lot of organs that causes downstream inflammation
But the two were studied in different people, for different purposes, with different endpoints, over different time frames so a direct numeric comparison is not valid
In male animals, GHK-Cu treatment after toxic exposure has restored sperm motility and reduced DNA fragmentation in some reports
Whey protein: In one study, administration of whey protein isolate resulted in clinical improvement in patients with psoriasis, regardless of whether the whey protein was given alone or in addition to topical or light therapies
Perhaps most importantly, GHK-Cu modulates matrix metalloproteinases, maintaining the balance between collagen production and degradation that characterizes youthful skin