The liver converts vitamin D2 and D3 into calcidiol, but they differ in their absorption rates. “Vitamin D2 is considered less effective in raising and maintaining blood levels of vitamin D compared ...

After, the liver converts that molecule into another type of vitamin D called 25-hydroxyvitamin D (calcidiol). And finally, the kidney transforms it to 1,25-dihydroxy vitamin D or (calcitriol ...

No matter what the source, though, vitamin D must be activated within the body—first through the liver, which converts vitamin D to calcidiol, and then in the kidney, which forms what's known as ...