Neither approach is universally superior
GHK-Cu modulates the expression of a large number of human genes studies using gene expression microarrays have identified over 4,000 genes whose expression is influenced by GHK-Cu, with effects spanning multiple functional categories including tissue remodeling, antioxidant defense, and growth factor signaling
Fisher A, Pittel Z, Haring R, Bar-Ner N, Kliger-Spatz M, Natan N, Egozi I, Sonego H, Marcovitch I and Brandeis R (2003) Ml muscarinic agonists can modulate some of the hallmarks in Alzheimer's disease: implications in future therapy
Enhanced fibroblast migration addresses the need for more repair cells in the hypovascular tendon
2016 Aug;54(3):778-787
It may provide significant analgesic effects for postherpetic neuralgia, alcohol-related neuropathy, diabetic neuropathy, and aphthous ulcers 22 , with minimal adverse effects