NOW Tests Resveratrol Products Purchased Online, Reveals Significant Problems

NOW has continued the testing program on products purchased online, with the company’s state of the art labs recently investigating 30 Resveratrol supplements purchased on Amazon. This is NOW's 18th round of product testing since 2017, all of which have raised serious concerns.

“Buyer beware” certainly applies to resveratrol, as we found significant problems with most products tested,” said Dan Richard, NOW Health Group VP of Global Sales and Marketing. “Once again, NOW will share this info with Amazon directly and with the FDA, in hopes of further action.”

This popular antioxidant supplement was first isolated in 1939 and has been sold by NOW since 2005. It is a polyphenol naturally found in grapes, red wine, peanuts, and herbs such as Japanese knotweed roots. There are two types of resveratrol: cis-resveratrol and trans-resveratrol. Both have the same molecular formula, but trans-resveratrol is more bioavailable and easier for the body to absorb. Japanese knotweed extract is the most common form of resveratrol in dietary supplements, and the trans-resveratrol portion is often found between 50-98%. Natural resveratrol also contains many trace levels of additional antioxidants, while synthesized resveratrol is isolated chemically and does not contain other synergistic components. 

NOW bought two bottles of each product from 30 brands, including NOW, on Amazon. Even before testing, most products seemed suspicious due to inflated potencies and mislabeling on the front label panels.

In addition to in-house testing, NOW sent one unopened bottle of each brand to Alkemist Labs, an industry-leading contract laboratory NOW has partnered with previously, for an independent report on the same products. Both NOW and Alkemist performed high-performance liquid chromatography (HPLC) testing. High-performance liquid chromatography (HPLC) with ultraviolet light detection (HPLC-UV) is the correct method to accurately measure the amount of trans-resveratrol in a sample. Resveratrol is a very interesting natural compound to test due to its complexity and labeling options. It's important to note that labeling for resveratrol dietary supplements is inconsistent across different brands.

Below are various examples of Supplement Facts panels to illustrate the extent of these differences and the potential confusion they may cause. NOW found two-thirds of the 30 brands tested have confusing or dishonest labeling for Resveratrol.  They also found that 21 out of 30 brands tested were below labeled potency, and 17 contained less than 10% 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 may not match numbers. 

• Both aSquared Nutrition Resveratrol Ultra Strength and NasaBe’Ahava Resveratrol 1000 mg claim to contain 1,000 mg of Resveratrol on the front panel. However, they only provide "8% potency yield" per 2 capsules, resulting in just 40 mg of Resveratrol per capsule, significantly lower than the claimed amount. Although aSquared Nutrition's test results indicated a higher amount than 40 mg, the initial claim remains deceptive. It is worth noting that aSquared Nutrition has failed NOW’s testing program 12 times out of 12 different products, resulting in a 100% failure rate.

• Purify Life Resveratrol Gummies claims “1500 mg per serving” on the front panel, but only 10 mg of 150:1 extract in the Supplements Facts panel.  This is deceptive and improper labeling.

• The front panel of the July 69 brand indicates that it contains 600 mg of Resveratrol per serving. However, the side panel lists the ingredients as "Resveratrol Blend 600 mg" and includes additional complicated information such as "Japanese Knotweed (10% Trans-Resveratrol) (Polygonum cuspidatum)(root), Japanese Knotweed (50% Trans-Resveratrol)(Polygonum cuspidatum)(root)" in very small font size. This labeling might be confusing for some people who are trying to understand what these percentages and ingredients mean.

• The side panel of Dr. Martin’s Nutrition Resveratrol lists "Trans-Resveratrol Complex" as 920 mg per two capsules, combined with nine other fruits and herbs. The side panel has an extremely small font size and is barely legible. The high claimed potency, unknown brand, and misleading labeling led us to include this product in testing.

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