25-hydroxy Vitamin D2

25-hydroxy Vitamin D2 (25(OH)D2) is one of the two main forms of vitamin D measured in the blood, the other being 25-hydroxy Vitamin D3. While Vitamin D3 is typically produced in the skin through sunlight exposure and obtained from animal-based sources, Vitamin D2 is derived from plant-based sources and supplements. 25(OH)D2 is converted in the liver from ergocalciferol (Vitamin D2) and reflects the body's intake of this form of the vitamin. It plays a role in calcium and phosphate metabolism, immune function, and overall bone health. Although Vitamin D2 is less potent and has a shorter half-life than Vitamin D3, both forms contribute to total vitamin D status.