Vitamin D2 (Ergocalciferol; Calciferol; Ercalciol) is one form of vitamin D with a double bond on the side chain, which differentiates it from Vitamin D3 (without a double bond on the side chain).

Doxercalciferol (1α-hydroxyvitamin D2; 1alpha-hydroxy VD2), a synthetic vitamin D2 analog, is a potent agonist/activator of VDR (Vitamin D receptor) with important biological activities.

Tacalcitol [1,24(R)-Dihydroxyvitamin D3; 1.alpha.,24R-Dihydroxyvitamin D3] is a vitamin D3 analog (isomer of Vitamin D3) that promotes normal bone development by regulating calcium.

Cholecalciferol (Vitamin D3; Colecalciferol), a secosteroid (a steroid molecule with one ring open), is a naturally occuring form of vitamin D; Upon metabolic activation, cholecalciferol is converted to the active form, 1,25-dihydroxy vitamin D3, which induces cell differentiation and prevents proliferation of cancer cells.

3-O-(2-Aminoethyl)-25-hydroxyvitamin D3 is a novel analog of vitamin D3 with potential biological activity.

Maxacalcitol (22-Oxacalcitriol) is a novel calcitriol analog without hypercalcemic side effects.

Alfacalcidol (1-hydroxycholecalciferol), an active metabolite of Vitamin D, is a potent and non-selective VDR activator medication that has been widely used in the treatment of osteoporosis.

Paricalcitol (trade name Zemplar) is a novel and potent vitamin D receptor (VDR) agonist developed by Abbott Laboratories for the prevention and treatment of secondary hyperparathyroidism (excessive secretion of parathyroid hormone) associated with chronic renal failure.

Calciol (5,6-trans-Vitamin D3), the inactive form of vitamin D3, is an enantiomer of vitamin D3 with important biological roles in calcium homestasis. In vivo, 5,6-trans-vitamin D3 increases tibia ash weight and bone mineralization in vitamin D-deficient chicks. 5,6-trans-Vitamin D3 induces intestinal calcium transport and bone calcium mobilization in anephric rats fed a low-calcium and vitamin […]

Ercalcitriol (RO-17-6218 or 1,25-dihydroxyvitamin D2, 1α,25-Dihydroxy Vitamin D2) is the active metabolite and circulating form of vitamin D2 formed by 25-hydroxylase in the liver and 25-hydroxyvitamin D-hydroxylase in the kidney.