I burned through a lot of trial and error skincare products also, can't say I found a dramatic/noticeable difference with many.
A good exfoliation with acid from time to time, good moisturizers or serum, or swap those out with collagen cream which feels remarkable. Focus for me is good skin condition and smoothness (also drink carrot juice, full of skin behooving vitamins).
And for actual skin health, tretinoin is my base (lowest % ).
And sun block of course.
Going to try a round of vitamin C serum again for sun damage on my upper chest, and the buffet + GHK serum (tho in all formulated GHK products, the % seems so low, 0.5%, 1% etc.)
But as to GHK for skin and scalp/hair, going to need to look further into how to formulate the bulk powder for application.
It's probably one of the only raved-about active ingredients I haven't tried yet.