In their definitive review, Dahan et al
The first group (G1) was given a normal basal diet as a negative control, while the other rats received a high-fat diet with 5% cholesterol
Tsuchihashi K, Okazaki S, Ohmura M, Ishikawa M, Sampetrean O, Onishi N, Wakimoto H, Yoshikawa M, Seishima R, Iwasaki Y, Morikawa T, Abe S, Takao A, Shimizu M, Masuko T, Nagane M, Furnari FB, Akiyama T, Suematsu M, Baba E, Akashi K, Saya H, Nagano O
GHK-Cu may modulate the follicular microenvironment through support of cell proliferation and anti-inflammatory effects
Tseng et al., 2022)
The In Vitro and Ex Vivo Hair Evidence and a Crucial Caveat The single most-cited experimental study behind copper-peptide hair claims is a 2007 report by Pyo and colleagues in Archives of Pharmacal Research