Is Taking Too Much Vitamin D A Real Concern? (Hint: Probably Not!)

Vitamin D is a vital nutrient involved in immune support, bone health, muscle function, and more.* … To reach optimal levels of 50 ng/mL (the true goal for vitamin D sufficiency), food alone just doesn’t cut it; you would need an unreasonable amount of vitamin-D-rich foods (like six servings of trout) to even make a dent.

That, folks, is where supplements come into play: Trusted nutrition and medical experts recommend 5,000 I.U. of vitamin D3 (the body’s preferred form) per day to help you get to—and stay!—above that 50 ng/mL threshold.

If you’re familiar with the vitamin D market, you may notice that this recommendation is higher than the average stand-alone supplement typically offers (many include less efficacious doses, like 400 I.U., 600 I.U., 1,000 I.U., or 2,000 I.U.), mainly because brands haven’t been keeping up with current science, don’t want the hassle of updating their old formulas, or are overly conservative, using the possibility of vitamin D toxicity (or getting too much vitamin D) to back their sub-efficacious doses, according to mbg’s director of scientific affairs Ashley Jordan Ferira, Ph.D., RDN.

But here’s the thing: That’s old-school science. While vitamin D toxicity is possible, it’s much more challenging to reach than you might think—so there’s really no excuse for brands not to up the ante. The risk of toxicity is not even relevant at useful, science-backed supplement doses, Ferira says.