Calcifediol, also known as calcidiol, 25-hydroxycholecalciferol, or 25-hydroxyvitamin D₃, is a form of vitamin D produced in the liver by hydroxylation of vitamin D₃ by the enzyme vitamin D 25-hydroxylase.

1.25% 25-hydroxyvitamin D₃

0.025% 25-hydroxyvitamin D₃

25-hydroxyvitamin D3 have been used in some studies to improve vitamin D status. Indications for their use include vitamin D deficiency or insufficiency, refractory rickets (vitamin D resistant rickets), familial hypophosphatemia, hypoparathyroidism, hypocalcemia and renal osteodystrophy and, with calcium, in primary or corticosteroid-induced osteoporosis.

Calcifediol may have advantages over cholecalciferol for the correction of vitamin D deficiency states. Calcifediol is better absorbed from the intestine and has greater affinity for the vitamin-D-binding protein, both of which increase its bioavailability.