Featured Monograph Update: St. John’s Wort

St. John’s wort is one of the most commonly used supplements for depression. We recently updated our monograph with some new data. Here’s the latest.

The World Federation of Societies of Biological Psychiatry and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce now recommend St. John’s wort as a treatment for mild to moderate forms of major depressive disorder. This aligns with the American College of Physicians recommendations, which state that it might be as effective and better tolerated than conventional antidepressants for mild to moderate depression. Its active constituents, hypericin and hyperforin, which affect serotonin levels, are thought to be the main reason for its antidepressant effects. Several other constituents might also be contributing factors.

But finding the right St. John’s wort product may be challenging. It’s important for patients to take products standardized to the appropriate amount of hypericin or hyperforin to get the clinical benefits. The CANMAT Taskforce recommends formulations standardized to about 0.2-0.3% hypericin and/or 5–6% hyperforin. Most clinical research has evaluated similar formulations. But third-party testing on herbal supplements is still limited, so verifying the contents of St. John’s wort products isn’t easy. There are natural inconsistencies in these ingredients – small differences, such as time of year, weather, and crop location, can impact the chemical makeup of a botanical ingredient like St. John’s wort. This can ultimately alter safety and effectiveness.

Lastly, remember that there are well-known drug interaction concerns with St. John’s wort. It’s a strong inducer of cytochrome P450 (CYP) 3A4 and can decrease concentrations of drugs metabolized by this enzyme. It also has serotonergic effects, so it should be used cautiously with other serotonergic drugs. Check out our recently updated monograph to learn more.