Vitamin DWhat is vitamin D?
Updated 3 Nov 2026
Short answer
Vitamin D is a fat-soluble vitamin. The skin makes it when UVB rays from the sun reach it, and a few foods such as fatty fish and egg yolks contain it.[1]
Supplements contain vitamin D3 (cholecalciferol) or vitamin D2 (ergocalciferol). D2 is made from yeast, D3 from sheep's wool fat or, for a vegan form, from lichen.[1] The body needs vitamin D to absorb calcium and to build bone.[1]
Sources (1)
- Vitamin D: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
More about vitamin d
How do you get vitamin D from sunlight and food?What is vitamin D used for?What vitamin D blood level is too low?Is vitamin D safe?Does vitamin D prevent fractures?Does vitamin D prevent colds and other respiratory infections?For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.