Studies have demonstrated that loss of mTOR activity may be detrimental during PD, as mTOR dysfunction has been shown in animal models of PD to lead to the death/apoptosis of dopaminergic neurons 11,12
In a landmark human trial comparing topical GHK-Cu to vitamin C and retinoic acid (tretinoin), GHK-Cu produced measurable collagen increases in 70% of study volunteers outperforming both comparator treatments (Abdulghani et al., 1998)
Or do you need supplements, too
Citation on PubMed Njalsson R, Ristoff E, Carlsson K, Winkler A, Larsson A, Norgren S
A copper peptide cream would work well as part of the "sandwich method." Tretinoin is known to be extremely drying to the skin because it promotes fast cell turnover, so sandwiching a copper peptide cream can help you lock in moisture
Otherwise, there would be nothing in the gut for it to bind to