My vit d level is 8 ng/ml what dose of vit d3 should i take and for how long?

10,000 iu D3 : I advise you take 10, 000 iu of vit d3 a day for 2-3 months then recheck your levels.Your goal is to get to 60-80 ng/ml ; you can adjust your dose as needed to maintain that- see http://www.Naturalnews.Com/027345_vitamin_d_exposure_sun.Html for details on how to adjust your dose. Once you find the dose that maintains you at 60-80 you should continue to take it indefinitely. Most need 6-8000 iu/day.