St. John's Wort
Real research in mild-to-moderate depression — but serious drug interactions make it one to discuss first.
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What it is
St. John's wort is a yellow-flowered plant (Hypericum perforatum) whose above-ground parts are made into teas and standardized extracts. It's one of the most studied herbal products for mood.
How it works
St. John's wort contains several active compounds, including hyperforin and hypericin. Lab studies suggest they may affect how brain cells recycle serotonin, norepinephrine and dopamine — loosely similar to how some antidepressants work — though which compounds matter most isn't settled. Hyperforin also switches on the liver enzymes and transporters that clear drugs from the body, which is the root of its many interactions.
What it's been studied for
Commonly taken for low mood, particularly mild-to-moderate depression.
What the evidence shows
Moderate, with important caveats: a Cochrane review of trials in people with major depression found standardized extracts outperformed placebo and performed similarly to standard antidepressants with fewer side effects, mostly in mild-to-moderate cases. But results were uneven — trials from German-speaking countries were notably more favorable than others, and large U.S. trials in major depression didn't show clear benefit over placebo. Evidence for severe depression and for use beyond about 12 weeks is limited.
Who should consider it
Research has focused on adults with mild-to-moderate depression, and some people in that group consider it together with their provider. It's not a good fit for anyone taking prescription medications without a pharmacist or provider review, anyone pregnant or breastfeeding, or anyone with bipolar disorder. Severe depression, or symptoms that make daily life hard, need professional care — and if you're having thoughts of harming yourself, contact your provider or call or text 988 in the U.S.
Amounts commonly studied
Studies typically used 900 mg per day of a standardized extract, commonly 300 mg three times daily, often standardized to 0.3% hypericin and/or a stated hyperforin content.
How to take it
Studies typically used 900 mg per day of standardized extract, split into three doses with meals, for 4 to 12 weeks; when it helps, the effect usually takes a few weeks to appear. Don't start it, stop it, or combine it with an antidepressant on your own — talk with your provider and pharmacist first, because stopping it can also shift the levels of other medications you take. Use sun protection while taking it, especially if you're fair-skinned.
Forms & absorption
Standardized extracts in capsules or tablets are the studied form; teas and tinctures vary widely in potency. Products differ in hyperforin content, which is linked to both the proposed mood effect and many of the drug interactions.
Food sources
None — St. John's wort is a medicinal herb taken as a standardized extract or tea, not a food.
Safety & interactions
This is one of the most interaction-prone supplements there is: it speeds up liver enzymes (CYP3A4) and drug transporters (P-glycoprotein), which can make birth control, blood thinners like warfarin, transplant drugs like cyclosporine and tacrolimus, HIV medications, and some heart, seizure and cancer drugs less effective. Combined with SSRIs, SNRIs, triptans or other serotonin-boosting drugs it can cause serotonin syndrome, and it can make skin more sensitive to sunlight. Avoid it during pregnancy and breastfeeding, with bipolar disorder (it may trigger mania), and before surgery — and never use it as a substitute for depression care.
Myths & what it won't do
Myth: because it's natural, it's gentler and safer than an antidepressant. Reality: it has more significant drug interactions than almost any other supplement, including ones that can make birth control fail or contribute to transplant rejection. Myth: it works for any kind of depression. Reality: the supportive research is mostly in mild-to-moderate depression, and large trials in more significant major depression were disappointing.
Common questions
- Can I take St. John's wort with my antidepressant?
- Not on your own. Combining it with SSRIs, SNRIs or other serotonin-boosting drugs can cause serotonin syndrome, a potentially dangerous reaction. Your provider can help you choose one approach safely.
- Does it affect birth control?
- Yes. It can lower hormone levels from pills and other hormonal methods, leading to breakthrough bleeding and unplanned pregnancy. If you're considering it, talk to your provider and plan on a backup method.
- How does it compare to prescription antidepressants?
- In trials of mild-to-moderate depression, standardized extracts performed similarly to standard antidepressants with fewer side effects, but the evidence is uneven and product quality varies. Depression deserves real care, so make this a conversation with your provider rather than a solo experiment.
The amounts listed here are what published research has used — not a prescription or a recommended dose for you. Confirm anything you plan to take with your own healthcare provider, especially if you take medications, are pregnant or nursing, or have a health condition.
Related goals
Research on St. John's Wort
Recommendations on this page are informed by published research. This is educational information, not medical advice.
- Linde K, Berner MM, Kriston L. St John's wort for major depression. Cochrane Database Syst Rev. 2008;(4):CD000448. View study →Note: Extracts beat placebo and matched standard antidepressants with fewer side effects in major depression, but results varied widely between trials and countries.
- Ng QX, Venkatanarayanan N, Ho CY. Clinical use of Hypericum perforatum (St John's wort) in depression: A meta-analysis. J Affect Disord. 2017;210:211-221. View study →Note: In mild-to-moderate depression, St. John's wort had response rates comparable to SSRIs with fewer dropouts; it didn't address severe depression.