NOW Health Group (Bloomingdale, IL) continued its testing program of supplements sold on Amazon. This round of testing focused on the popular herb St. John’s wort.

Results showed that every product (except for NOW’s brand) failed potency testing. Several samples contained synthetic dyes, which are commonly used to make low-quality or adulterated products appear authentic, the company said.

According to NOW, St. John’s wort (Hypericum perforatum) is used to support mood balance and emotional well-being. The key active compounds, hypericin and pseudo-hypericin, are responsible for its beneficial properties and typically standardized to 0.3 percent.

NOW purchased two bottles each of St. John’s wort supplements (including its own brand) from Amazon in August 2025. One bottle was tested at NOW’s state-of-the-art in-house labs and the other was sent to Alkemist Labs.

Of the 22 tested brands, only NOW brand met the label claim for total hypericin and contained no synthetic dyes. Nine brands contained synthetic dyes, five brands had no detectable hypericin, none of the gummies had any detectable hypericin and six products contained non-standardized material at rates as low as 0.03 percent, the company said.

“We are accustomed to seeing abysmal test results in at least some of the brands we buy from Amazon for this testing program, but this time we were shocked to find that they all failed, and only NOW St. John’s Wort met the label claim for total hypericin and showed no evidence of dye adulteration,” said Katie Banaszewski, senior director of quality at NOW. “What stands out most to me is the strong evidence that none of these brands used fit-for-purpose testing, if they tested at all. Our in-house analytical testing, paired with Alkemist Labs’ independent verification, underscores the importance of scientifically valid methods.”

For more information, visit www.nowfoods.com.