Ingredient guide
Vitamin D basics before you choose
A clear introduction to D2, D3, units, Daily Value, food sources, sun exposure, and clinical context.
Whole for Good editorial guide · Content version July 18, 2026
Understand the units
Vitamin D may be shown in micrograms and international units. Compare serving sizes and amounts rather than relying on a product name alone.
More is not automatically better
Needs vary, and high-dose products deserve added context. A clinician may use health history, diet, medicines, and laboratory information when advising an individual.
Consider the complete picture
Food, fortified products, sun exposure, and supplements can all contribute to intake.