NOW Health Group’s (Bloomingdale, IL) latest round of testing investigated 30 resveratrol products purchased on Amazon. This was the 18th round of testing since 2017, all of which “raised serious concerns,” according to the company.

Resveratrol is a popular antioxidant found naturally in grapes, red wine, peanuts and herbs. Japanese knotweed extract is the most common form of resveratrol used in dietary supplements.

NOW stated that it bought two bottles of each product (including its own brand) and many seemed “suspicious due to inflated potencies and mislabeling on the front label panels.” In addition, NOW said it also sent one unopened bottle of each to California-based contract testing laboratory Alkemist Labs.

Both NOW and Alkemist Labs used high-performance liquid chromatography (HPLC) testing. They determined 21 out of the 30 brands tested below label potency and 17 contained less than 10 percent of claimed potency. Many brands display the highest potency number on the front panel and in Amazon search terms, but “tricky” labeling on the side panel did not always match the numbers, NOW stated.

“The results above further substantiate the fact that the market is saturated with unscrupulous companies that make false claims,” said Dan Richard, vice president of global sales and marketing at NOW. “Consumers should be cautious when buying from lesser-known brands and opt for trusted, honest and transparent brands.”

For more information, visit www.nowfoods.com.