Tablets and dry powder filled capsules are surrounded by air and continually lose potency throughout the manufacturing process, and then continue to do so even while sitting in a bottle on the shelf.

As a result, many of the products on the market today contain much less resveratrol than is stated on their labels. Indeed, Consumer Labs tested 13 of the leading resveratrol products and their findings confirmed this.

NPR brought this public with a story, a link to which is provided for you here.