Guys, My son (13 years old) is pretty active in sports and has broken 4 bones over the years. Blood showed calcium at optimal levels, but Vitamin D was at 9 ng/ml (30 - 100). After 6 weeks of 3,000 iu daily of Vitamin D, we got his levels up to 36 ng/ml (30 - 100). Really disappointed with the quality of answer I get from docs, seem they don't know shit. My question: Is supplementing with Vitamin D a possible issue only if your levels are over 100 ng/ml...or can someone, in this case a 13 year old, have toxic issues with Vitamin D supplementation while taking 3,000 iu's, but with levels, still at the lower end of the range? Thank you.