Vitamin D
To the overview: Vitamins Synonyms Cholecalciferol Occurrence and structure Cholecalciferol/Vitamin D is the precursor of Calcitriol. It is synthesized from cholesterol. The cholesterol is split in the skin by exposure to sunlight (i.e. UV light) and thus becomes cholecalciferol, which is actually vitamin D. The active form, however, is calcitriol, whose chemical name is actually … Vitamin D