After being made in the skin or absorbed in the intestine, vitamin D gets into blood circulation.
All forms of vitamin D- 7-dehydrocholesterol, pre-vitamin D3, and vitamins D2 and D3 are all converted to 25(OH)D, the biologically inactive storage form of vitamin D, stored in the liver long term.
When needed, Vitamin D is then converted in the kidneys to the biologically active form (short life), 1α,25(OH)2D.
When needed, Vitamin D is then taken up by vitamin D receptors in cells (including white blood cells) and tissues throughout the body.
