|Jmol-3D images||Image 1|
|Molar mass||400.64 g/mol|
| (what is: / ?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Alfacalcidol (or 1-hydroxycholecalciferol) is an analogue of vitamin D used for supplementation in humans and as a poultry feed additive.
Alfacalcidol has a weaker impact on calcium metabolism and parathyroid hormone levels than calcitriol, however alfacalcidiol has significant effects on the immune system, including regulatory T cells. It is considered[by whom?] to be a more useful form of vitamin D supplementation, mostly due to much longer half-life and lower kidney load.
- Biological effects of various regimes of 25-hydroxyvitamin D3 (calcidiol) administration on bone mineral metabolism in postmenopausal women, Clin Cases Miner Bone Metab. 2009 May–Aug; 6(2): 169–173; 
- Oral calcitriol versus oral alfacalcidol for the treatment of secondary hyperparathyroidism in patients receiving hemodialysis: a randomized, crossover trial, Can J ,Clin Pharmacol Vol 15 (1) Winter 2008:e36 -e43; January 9, 2008; 
- Alfacalcidol treatment restores derailed immune-regulation in patients with undifferentiated connective tissue disease, Autoimmunity Reviews, August 2010;
- Superiority of alfacalcidol compared to vitamin D plus calcium in lumbar bone mineral density in postmenopausal osteoporosis, Rheumatol Int. 2006 Mar;26(5):445-53. Epub 2005 Nov 10; 
- VDI Product Data