When you buy your vitamin D supplements over-the-counter be careful, they may be less potent than the labels claim, researchers from Kaiser Permanente reported in JAMA Internal Medicine.

Vitamin Dvitamin

vitamin D supplements can have as little as 9% and as much as 146% of what their labels claim

“We were surprised by the variation in potency among these vitamin D pills. The biggest worry is for someone who has low levels of vitamin D in their blood. If they are consistently taking a supplement with little vitamin D in it, they could face health risks.”

The FDA (Food and Drug Administration) has been trying to tighten up the labeling of dietary supplements for many years

USP verification mark

USP Verified vitamin D supplements were generally more accurate than the other containers they tested

  • 55 bottles of OTC vitamin D supplements
  • The products came from 12 different manufacturers
  • They purchased the products at five different shops in Portland
  • The compounded vitamin D was made by a Portland compounding pharmacy