Nutrients & Supplements
Vitamin A
A fat-soluble vitamin essential for vision, immunity, and cell differentiation.
Vitamin A encompasses a group of fat-soluble compounds including retinol, retinal, retinoic acid (preformed vitamin A from animal sources), and carotenoids like beta-carotene (provitamin A from plant sources). It is essential for vision, immune function, reproduction, and cellular communication. In hair biology, retinoic acid regulates hair follicle stem cell activation and sebaceous gland function. Both deficiency and excess vitamin A can cause hair loss, making proper dosing critical. The UL for preformed vitamin A is 3,000 mcg RAE/day for adults.