St. John's wort – Hypericum perforatum – is a yellow flower that grows wild in Sweden and large parts of Europe. It is also the natural supplement with the most clinical research supporting its use for treating mild to moderate depression. There are hundreds of studies, a number of systematic reviews, and in several European countries, St. John's wort extract is approved as a medicine for depression. In Sweden, it is sold as a dietary supplement.
Here we have St. John's Wort from Swanson.
How does St. John's wort work?
The active ingredients are hypericin and hyperforin. The mechanism is in many ways similar to modern antidepressants: St. John's wort inhibits the reuptake of serotonin, dopamine, and norepinephrine in synapses – much like SSRI and SNRI preparations, but with a broader and milder mechanism of action. Hyperforin is considered to be the main active ingredient for its antidepressant effect.
What does the research say?
A Cochrane review of 29 clinical trials with a total of almost 5500 participants concluded that St. John's wort extract is significantly more effective than placebo for mild to moderate depression, and as effective as standard antidepressant medications – with fewer side effects. This is a strong result for a natural supplement. However, the evidence is weak for severe depression, and St. John's wort should not be used as a substitute for medical treatment for serious mental illness.
Important interactions to be aware of
St. John's wort is one of the supplements with the most known drug interactions. It activates enzyme systems in the liver that accelerate the breakdown of a wide range of medications and can make them less effective. Medications affected include birth control pills, blood thinners like warfarin, HIV medications, and certain heart medications. Never take St. John's wort together with SSRIs or SNRIs without a doctor's approval. If you are taking prescription medications – always consult a doctor or pharmacist first.
If you are not taking any of these medications and are seeking natural help for mild depression, St. John's wort is one of the best-documented alternatives available. Standard dose: 300 mg three times daily (0.3% hypericin). The effect is usually noticed after 2–4 weeks of consistent use.
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