nutrient

Vitamin D2 (ergocalciferol)

A vitamin D form produced by some fungi and used in some fortified foods and supplements.

Vitamin D2 and D3 both enter vitamin D metabolism, while their source and product formulation remain distinct.

What the form means

Ergocalciferol is one of the forms included under vitamin D. Vitamin D2 and D3 have distinct chemical structures and sources.

Forms

  • D2 is one of the two main forms of vitamin D.

    Vitamin D2 (ergocalciferol) is a named chemical form within its parent vitamin family.

Worth knowing

  • The fungal form. Vitamin D2, or ergocalciferol, is produced by some fungi and is used in some fortified foods and supplements. Its source is a useful label detail when comparing products.

A closer look

A blood test measures the combined supply

After absorption, D2 is converted through vitamin D metabolism and contributes to circulating 25-hydroxyvitamin D. A total 25-hydroxyvitamin D result combines the contribution from D2 and D3; it does not identify the food or supplement that supplied them.

References

Source-checked local draft.
Human editorial review pending.

  1. NIH Office of Dietary SupplementsVitamin D: Fact Sheet for Health ProfessionalsChecked 2026-09-05