St. John’s Wort Rarely Marketed for ADHD; Product Degraded by End of Trial – AHPA Comments on JAMA Study

June 11, 2008 – The newly published Journal of the American Medical Association (JAMA) study that finds St. John’s wort (Hypericum perforatum) comparable to placebo for attention-deficit/hyperactivity disorder in children and adolescents, has several crucial flaws, the American Herbal Products Association (AHPA) says.

The randomized and placebo-controlled trial published in the June 11, 2008 issue involved 54 children ages 6 to 17 years. The 27 children in the intervention group received 300 mg of H. perforatum three-times daily for eight weeks. Wendy Weber, ND, PhD, et al., found no significant difference between St. John’s wort and placebo with respect to improvement of the symptoms of ADHD.

According to Weber et al., the most common herbal treatments used by children with ADHD are St. John’s wort, Echinacea species, and ginkgo. However, as AHPA President Michael McGuffin points out, the marketing of St. John’s wort for ADHD is not common at all. In fact, the supporting reference for the authors’ assertion was a survey conducted in 2000-2001 that found five out of 117 children with ADHD had taken St. John’s wort at some time in their life. These five children had not necessarily taken St. John’s wort for ADHD and were not necessarily taking it at the time of the survey – hardly a supportive reference for the researchers’ assertion.

Furthermore, by the authors’ own admission, the product had seriously degraded by the end of the trial. The H. perforatum used in the study was reported to be standardized to 0.3% hypericin; however, at the end of the study the product contained only 0.13% hypericin and 0.14% hyperforin. “I don’t believe that this test material would pass muster if the proposal was submitted to NIH’s National Center for Complementary and Alternative Medicine (NCCAM) today because something as basic as ensuring the quality through the duration of the trial was not assured,” said Steven Dentali, Ph.D., AHPA’s Chief Science Officer and past chairperson of NCCAM’s Product Quality Working Group.

“It is possible that a product standardized to at least 3% hyperforin could benefit children with ADHD symptoms if it were delivered in a method that limits oxidation,” Weber et al. note in the study.

“The degradation of the product to less than half the amount of the marker compound means the quality of this product was seriously impaired by the end of the study,” said McGuffin. “Overall, this is a study of an uncommon use of St. John’s wort that used a poor quality product.”


The American Herbal Products Association (AHPA) is the only national trade association devoted to herbal issues. Representing the core of the botanical trade—comprised of the finest growers, processors, manufacturers and marketers of herbal products—our mission is to promote the responsible commerce of herbal products. AHPA committees generate self-regulations to ensure the highest level of quality with respect to the way herbal products are manufactured, labeled, and sold. Website:

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