Vitamin C

Water-soluble vitamin, essential cofactor of prolyl hydroxylase and lysyl hydroxylase, the enzymes that stabilise the collagen triple helix. Without vitamin C, collagen is poorly formed (scurvy). It is also a powerful antioxidant that protects skin cells from oxidative stress. A University of Otago study (2025) showed a tight correlation between plasma vitamin C levels and skin thickness. Sources: kiwi, peppers, citrus fruits, broccoli.