How Much Vitamin D Is Too Much? Rethinking the Upper Limit
Dr. Kumar’s Take:
Most people are told to avoid high doses of vitamin D, but this paper by Dr. Reinhold Vieth questions that advice. Based on human studies, he argues that daily doses up to 10,000 IU of vitamin D3 are not only safe but may be necessary for many people to reach optimal blood levels—especially those who get little sun. The current upper limit of 2,000 IU/day is likely too low. If you’re supplementing with vitamin D, consider tracking your blood levels and working with a provider, but don’t fear doses in the 4,000–10,000 IU range if you are otherwise healthy.