 The USP, NSF, and Consumer Lab seals mean a product contains what's on the label, is free of tested contaminants, and disintegrates fast enough to enter the bloodstream. However, they do not mean the product delivers the promised health benefits. Finally, your doctor needs to know if you take supplements because they can interfere with the other drugs you're taking, making them more potent and possibly toxic, or less potent and therefore ineffective. You are listening to 103.5 FM and WTOP.com.