What’s The Difference Between Vitamin D2 and Vitamin D3?
Two different forms of vitamin D are used in supplements and fortified foods. Vitamin D2, also called ergocalciferol, is manufactured through the ultraviolet irradiation of a substance called ergosterol that comes from yeast. Vitamin D2 is vegan. Vitamin D3, also called cholecalciferol, is made by the ultraviolet irradiation of a substance derived from sheep’s wool. Some research suggests that vitamin D2 and vitamin D3 are absorbed equally well,9 although other studies suggest that vitamin D3 is better absorbed.10 If you are treated for a vitamin D deficiency, you may find that your health care provider recommends taking a higher dose of vitamin D2 than of vitamin D3 to compensate for possible differences in absorption.2 This is an area of active research that we will continue to follow.
