A 15-year-old girl tells you she started to take St. John’s Wort several weeks ago on her own to treat mild depression. Her friend recommended that she buy a standardized preparation. She asks your advice.
Which of these statements is TRUE?

The correct answer is C.


"Standardization" generally means taking a concentrated extract of an herb and adjusting it to contain a specified percentage of a particular compound. However, herbs have complex chemical constituents, and the physiologic effects may be due to several constituents or a combination of ingredients or may be unknown. Sometimes the standardized ingredient is simply a marker rather than the actual active ingredient.

Most trials of St. John's Wort have used a German extract called LI 160, or Jarsin, which is standardized to 0.3% hypericin. Many other St. Johns Wort products are also standardized to contain 0.3% hypericin, but there is some dispute as to whether this is the main or only active chemical constituent.

In recent studies evaluating various standardized St Johns Wort preparations, substantial variation was documented in the concentration and physiologic activity of different products. Label claims do not ensure purity or potency.

These websites have more information about standardization and quality control issues for herbal products:, an independent organization performing quality tests on herbs and dietary supplements:

American Botanical Council's Ginseng Evaluation Program: Informational and commercial site with reprint of a 1998 LA Times article, "Remedy's U.S. Sales Zoom, but Quality Control Lags":


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Last Updated: August 24, 2001
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