It is also produced endogenously when ultraviolet (UV) rays from sunlight strike the skin and trigger vitamin D synthesis.
Vitamin D (also referred to as 'calciferol') is a fat-soluble vitamin that is naturally present in a few foods, added to others, and available as a dietary supplement. For a reader-friendly overview of Vitamin D, see our consumer fact sheet on Vitamin D.įor information on vitamin D and COVID-19, see Dietary Supplements in the Time of COVID-19. This is a fact sheet intended for health professionals.