Cholecalciferol (vitamin D3) is a form of vitamin D that is commonly used in dietary supplements. Cholecalciferol is synthesized by humans in the skin when exposed to ultraviolet-B (UVB) rays from sunlight. However, for individuals who are insufficiently exposed to sunlight, vitamin D must be provided through the diet 1.


  1. PDR for Nutritional Supplements. Montvale, NJ: Physicians’ Desk Reference, Inc, 2008.