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Alfacalcidol ball-and-stick.png
IUPAC name
Other names
Alphacalcidol; 1-Hydroxycholecalciferol
ATC code A11CC03
41294-56-8 YesY
ChemSpider 4445376 YesY
DrugBank DB01436 YesY
Jmol-3D images Image
KEGG D01518 YesY
PubChem 5282181
UNII URQ2517572 YesY
Molar mass 400.64 g/mol
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N verify (what isYesY/N?)
Infobox references

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[1] and parathyroid hormone levels[2] than calcitriol, however alfacalcidiol has significant effects on the immune system, including regulatory T cells.[3] It is considered to be a more useful form of vitamin D supplementation, mostly due to much longer half-life and lower kidney load.[4] It is the most commonly prescribed vitamin D metabolite for patients with end stage renal disease, given that impaired renal function alters the ability to carry out the second hydroxylation step required for the formation of the physiologically active form of vitamin D, 1,25-dihydroxyvitamin D3. Alfacalcidol is an active vitamin D3 metabolite, and therefore does not require the second hydroxylation step in the kidney. [5]

Used as a poultry feed additive, it prevents tibial dyschondroplasia and increases phytate bioavailability.[6][original research?]


  1. ^ 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; [1]
  2. ^ 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; [2]
  3. ^ Alfacalcidol treatment restores derailed immune-regulation in patients with undifferentiated connective tissue disease, Autoimmunity Reviews, August 2010;
  4. ^ 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; [3]
  5. ^ Alfacalcidol in the therapy of renal bone disease. Ritzerfeld M, Klasser M, Mann H. Int J Clin Pharmacol Ther. 2001 Dec;39(12):546-50.PMID:11770836
  6. ^ VDI Product Data