Q. I have read that you can’t trust the label on some supplements. I guess the FDA doesn’t bother to check them.
If it says USP on the container, can we assume the product is what it says it is?
A. We were appalled to read the research published in JAMA Internal Medicine (online Feb. 11, 2013) showing wide variations in compounded and OTC vitamin D pills. The scientists found that potency ranged from 9 percent to 146 percent of the dose listed on the label.
You are right that the FDA does not have the resources to check the quality of most supplements. You mention USP, the United States Pharmacopeia. This nongovernmental scientific organization has set quality standards for medicines for nearly 200 years.
We spoke with a representative who told us that the USP-Verified seal is backed by careful quality monitoring, including off-the-shelf vitamin testing. You can learn more about USP verification and see what the symbol looks like at the organization’s site.