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St. John's Wort

Also indexed as:Hypericum perforatum, Saint John's Wort, St. John's Wort
St. John's Wort: Main Image© Steven Foster
Botanical names:
Hypericum perforatum

How It Works

The major constituents in St. John's wort include hypericin and other dianthrones, flavonoids, xanthones, and hyperforin.40 While it was previously thought the antidepressant actions of St. John's wort were due to hypericin and the inhibition of the enzyme monoamine oxidase,41 current research has challenged this belief, focusing on other constituents, such as hyperforin, and flavonoids.42, 43, 44 Test tube studies suggest that St. John's wort extracts may exert their antidepressant actions by inhibiting the reuptake of the neurotransmitters serotonin, norepinephrine, and dopamine.45 This action is possibly due to the constituent hyperforin.46 St. John's wort is able to act as an antidepressant, by making more of these neurotransmitters available to the brain.

How to Use It

The standard recommendation for mild to moderate depression is 500-1,050 mg of St. John's wort extract per day.47, 48, 49 Results may be noted as early as two weeks. Length of use should be discussed with a healthcare professional. For more severe depression, higher intakes may be used, under the supervision of a healthcare professional.

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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2015.