SLC23A1 (Solute Carrier Family 23 Member 1): SLC23A1 is a protein that plays a key role in transporting ascorbic acid (vitamin C) into cells. It is essential for maintaining optimal vitamin C levels, which support immune function, collagen production, and antioxidant defense. Genetic variations in SLC23A1 can affect individual vitamin C needs and influence susceptibility to conditions related to vitamin C deficiency.