KLOW is a four-peptide blend supplied in a single vial: KPV (10 mg), GHK-Cu (50 mg), BPC-157 (10 mg) and TB-500 (10 mg). Each constituent has its own published literature. No published study of this four-peptide combination was identified, so the literature summarised here concerns the individual constituents. KPV (Lys-Pro-Val) is the melanocortin-derived tripeptide alpha-MSH(11-13), studied in intestinal epithelial and immune cell culture and in mouse colitis models. GHK-Cu is the copper(II) complex of glycyl-L-histidyl-L-lysine, studied in rat wound models. BPC-157 is a synthetic pentadecapeptide studied mainly in rodent tendon and angiogenesis models. TB-500 is a name used for synthetic thymosin beta-4, a 43-residue actin-sequestering peptide.