Report Silver Bullet For Cancer: Metal Can Kill Some Tumours Better Than Chemotherapy With Fewer Side Effects in Gold and other precious metals Posted March 1, 2012 It is quite difficult to overdose on it, but you know what some folk are like - they go a bit bonkers! My levels were at 17 and after taking between about 3,000/6000mg a day (not iu) and they went up to about 120 in 3 months. Think our figures on sunlight exposure are about the same. They say about 20000 per 20 minutes depending on skin tone. Another thing to remember is that if your magnesium levels are low you can't convert d3. Interesting fact since magnesium was normally absorbed from hard water sources and these days we tend to purify and soften water. Could be one reason why there are still people living in sunny climes that get a lot of exposure to sunlight but still have a d3 deficiency?