How Much Vitamin D Per Day? 600-800 IU — and Why More Won't Make You Stronger
The RDA is 600 IU (800 IU past 70), set against a blood level of 20 ng/mL. About 56% of athletes fall short. But across two dozen randomized trials, correcting a low level reliably raised the number in your blood without reliably making you stronger — and 10,000 IU a day for three years lowered bone density.
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