Usage & Safety

Safely getting the benefits of St. John's Wort comes down to the right dose, enough patience to let it work, and awareness of how it interacts with other medications.

Recommended dosage

900 mgtypical daily dose (300 mg, three times a day)

up to 1800 mgconsidered safe and effective for some

300–600 mglower range for sensitive individuals

≥ 3%hyperforin the extract should be standardized to

It takes time to work

St. John's Wort is not a quick fix. Most people need 3–4 weeks of consistent daily use to notice a difference, and some need 6–8 weeks. Plan to stay with it for at least six to eight weeks before judging whether it helps.

Talk to your provider first

Check in with a healthcare provider before starting — especially if you are pregnant, nursing, or have allergies. Because St. John's Wort shares liver-enzyme pathways with many drugs, anyone taking medication for bipolar disorder, schizophrenia or seizures should get advice first. Disclose every medication and supplement you take.

Side effects

It is generally well tolerated, and most side effects are mild and short-lived. The most common are headaches, fatigue, vivid dreams, a temporary uptick in anxiety, and increased sensitivity to sunlight. Feeling slightly "off" in the first days is normal; serious reactions are rare.

Interactions with medications

It can reduce the effectiveness of birth-control pills and protease inhibitors, and combining it with SSRIs or other serotonin-raising drugs carries a risk of serotonin syndrome. Always disclose what else you take before starting.

Photosensitivity: St. John's Wort can make your skin more sensitive to sunlight. Use a high-SPF sunscreen, wear protective clothing, and limit midday sun exposure.

Severe depression

The evidence is strongest for mild-to-moderate depression. For major or severe depression it is much less reliable on its own and should not replace intensive treatment. Severe cases need professional intervention — and anyone experiencing suicidal thoughts should seek immediate help.

Pregnancy, breastfeeding and surgery

Safety during pregnancy and breastfeeding has not been established, so avoid it unless a provider approves. Because it interacts with anesthesia and other surgical medications, tell your provider well in advance of any operation; you may need to stop taking it beforehand.

Beyond depression

Researchers continue to study St. John's Wort for seasonal affective disorder (SAD), OCD, menopausal symptoms and wound healing.