I had the good fortune a couple of weeks ago when I was visiting Los Angeles to speak with an osteopathic doctor from Colorado who has treated and cured many of his patients with D3. The gist of what he told me (sorry, I didn't have any writing instruments with me at the time of the conversation so this is in my memory bank) was that many ailments are healed with vitamin D3 after 2-3 months on the hormone (he refers to it as a hormone, not a supplement). He suggested that I first get my D levels checked at a doctor's office. Once I know the baseline, I can start taking 8,000 iu of vitamin D3 a day. After 3 months, I should get the levels checked again. In summertime some people would be able to drop this daily dose to about 4,000 iu/day or less, but you won't know unless you get your levels checked. He told me people will be very surprised to see how deficient they are in D. Even those that live in sunny climates like Los Angeles are surprisingly deficient in D3.
One of his patients with erectile dysfunction was cured after a two months on D3. Unfortunately, the patient was so thrilled with the results that he started taking a lot more than what was recommended! A blood test showed his D levels soared too high and he had to come off it for about two months. After two months he was deficient again.
The good doctor also told me that 90% of his patients suffering from migraines were cured after being 2-3 months on D3. The key is to give it 3 months at 8,000/day dosage. He recommended the vitamin d council website for further research: http://www.vitamindcouncil.org/