heart health, and other processes. While vitamins D2 and D3 can both help boost vitamin D levels in people with a deficiency, research suggests that vitamin D3 is more efficiently absorbed and ...

There are two primary forms of vitamin D—D2 (ergocalciferol) and D3 (cholecalciferol). A vitamin D test, specifically the 25-hydroxyvitamin D blood test, is used to diagnose deficiency.