vitamin D2 and D3 are called out on various labels, too. What exactly is the difference between D, D2, and D3? Are they all forms of the same vitamin, or is each one a completely different nutrient ...

vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). While both forms serve similar functions in the body, there are differences in their sources, metabolism, and effectiveness.

There are two types of vitamin D supplements available for over-the-counter purchase (vitamin D2 and vitamin D3). Vitamin D3 is the type that most experts believe should be utilized in clinical ...