I have been taking D3 but only 1000IU's per day. Does anyone have any further info on the 1000IU per 25 lbs of body weight dosage? I have not seen that recommendation. I have never been tested, but I am sure I am deficient, I wake up when its dark, go to work where there are no windows all day, and then get done when it's dark. I try to get out during the day for a 20-30 minute walk, but I live in New Hampshire, where the rays aren't especially strong anyways.