Japanese researchers have found that vitamin C (VC) can thicken the skin by activating genes that control cell growth. For the elderly population with damaged or gradually thinning skin, VC is an effective means to enhance the skin's ability to self repair and regenerate. This achievement was achieved through a collaboration between Tokyo Metropolitan Health and Longevity Medical Center, Hokuriku University, and Leyden Pharmaceuticals. The relevant paper was published in the latest issue of the Journal of Dermatology Research. The skin is the first line of defense for the human body to resist external threats. However, as age increases, the outermost layer of the epidermis gradually becomes thinner and its protective ability weakens. About 90% of the cells in the epidermis are keratinocytes, which originate from the deep layers of the epidermis and gradually move towards the surface, ultimately forming the protective barrier of the skin. To verify the mechanism of action of VC, researchers used an experimental model simulating human skin and added VC at concentrations of 1.0 and 0.1 millimoles, respectively. The results showed that the samples treated with VC exhibited significant thickening of the cell layer on day 7, thickening of the epidermis and slight thinning of the stratum corneum on day 14, indicating that VC can promote cell renewal. In addition, the number of active dividing cells significantly increased, indicating enhanced cell proliferation activity. Further analysis shows that VC activates cell proliferation related genes by promoting DNA demethylation. Methylation inhibits gene expression, while VC maintains TET enzyme activity, thereby releasing inhibition and promoting gene expression. The study identified over 10000 demethylated regions and increased the expression levels of 12 key genes by 1.6-75.2 times. When researchers used TET enzyme inhibitors, these effects were significantly reversed, further confirming the role of VC through TET enzyme mediated demethylation mechanism. (New Society)