What forms of vitamin D are found in dietary supplements?
The two forms of vitamin D used in dietary supplements are ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Ergocalciferol is sometimes considered a vegetarian source of vitamin D since it can be plant-derived. However, yeast is also commonly used as a source of D2 as are other fungi (like ergot). Some individuals would regard these microbially produced forms of D2 as animal-based, while others would not.