25-hydroxy calcifediol, also known medically as cholecalciferol, is the precursor to vitamin D3, which can be hydroxylated to produce 25-hydroxy calcifediol, the active product and the main form in which vitamin D3 is stored in our bodies. It is also an important intermediate in the metabolism of vitamin D, which is stable, while vitamin D itself has no biological activity and is converted to the 25-hydroxy calcifediol for its biological effect.
25-Hydroxy calcifediol is better absorbed in the body than vitamin D3. It is directly absorbed by the intestinal tract and enters the circulation, effectively increasing the levels of 5-hydroxyvitamin D3 in the blood. 25-Hydroxy calcifediol is important for the maintenance of normal development, bone and muscle function, and so on.