GHK (glycyl-L-histidyl-L-lysine) is a tripeptide, occurring in human serum, plasma, saliva, and urine, 1 which has a strong affinity for copper ions (Cu 2+ ) to form GHK-Cu complexes. In subsequent studies, its benefits for skin health were revealed. Miller D. M. and Park J. R.'s research 2,3 indicated that GHK-Cu could reduce the production of TNFα and IL-6 by blocking the activation of NF-κB p65 and p38 MAPK to inhibit excessive inflammatory responses. In Hong's study, 4 GHK-Cu was found to affect gene expression, including YWHAB, MAP3K5, LMNA, APP, GNAQ, F3, NFATC2, and TGM2, to regulate the immune system and tissue regeneration. Furthermore, Siméon A. and Wegrowski Y. 5,6 discovered that GHK-Cu could stimulate the synthesis of glycosaminoglycans (GAGs), increase the accumulation of chondroitin sulfate, and boost collagen I production. Moreover, GHK-Cu was found to increase skin clarity and reduce wrinkles. 7,8 Therefore, GHK-Cu has been widely used in skin care products as a key active ingredient.Another commonly used skin care compound is hyaluronic acid (HA). As an endogenous substance, it distributes throughout human body, including eye, cavum articulare, and skin. 9 In skin, HA is synthesized by hyaluronan synthases (HAS1, HAS2, HAS3), 10 and its level declines dramatically during aging. For example, the epidermal HA content decreases from 0.03% in 19-47-year-old women down