How long does it take for vitamin d2 to get in your system?

Days but months to: see response. I have seem many do poorly on D2, including D3 concentrations going down. 20-25% of the population do not convert D2 to D3 well. Thus would avoid in favor of D3. Read: http://ajcn.nutrition.org/content/84/4/694.full, a relevent discussion. The D- vitamins are derivatives of cholesterol. Intake & absorption are low on a low fat diet, thus avoid. Desirable D3 conc. in the 70 range.

DON'T TAKE D2!!!: I'm not sure & don't even want to take the time to look it up because my advice is STOP TAKING D2 immediately. An analysis of 50 studies showed those who take D3 had a 6% decrease in mortality whereas D2 actually increased mortality by 2%! NO ONE SHOULD TAKE D2! See http://bit.ly/1hC250m Please stop D2 and switch to 5-8000 iu/day of D3. Please share this info with the doc who prescribed D2!!!