Compared to manufactured peptides like Matrixyl (palmitoyl pentapeptide-4), GHK-Cu happens normally in human tissue and illustrates broader organic action
Bommier C, Tsang M, Nobel BM, Thompson C, Casulo C, Hildebrandt M , Rosenthal AC, Mou E, Durani U, Williams AM, Yost K, Larson MC, Gysbers B, Maurer MJ, Feldman AL, Jaye DL, Chihara D, Lossos LS, Strouse C, Kahl BS, Habermann TM, Flowers CR, Dueck AC, Cerhan JR, Cohen JB
Selected Publications Crowell PD, Fox JJ, Hashimoto T, Diaz JA, Navarro HI, Henry GH, Feldmar BA, Lowe MG, Garcia AJ, Wu YE, Sajed DP, Strand DW, Goldstein AS, "Expansion of luminal progenitor cells in the aging mouse and human prostate", Cell Reports 28 (6): 1499-1510 (2019)
It's the natural scent of glutathione, which some reviewers described as "eggy." It's not rancid as you might think, though