St. John's wort supplement: what it can do and why interactions matter
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- St. John's wort extract, 0.3% hypericin. Best for: Adults on no medications whose doctor has okayed a trial for mild low mood. See options on Amazon
- St. John's wort capsules, higher strength. Best for: Adults following specific advice from their provider. See options on Amazon
- St. John's wort liquid extract. Best for: People who prefer drops. See options on Amazon
What St. John's wort is
St. John's wort is a yellow-flowered plant used in Greek, Islamic and Chinese traditional medicine. The National Center for Complementary and Integrative Health (NCCIH) says the name likely refers to John the Baptist, since it blooms around his feast in late June.
Historically it was used for depression, stomach ulcers, colds and wound healing. Today it is most widely promoted for depression symptoms, plus menopause symptoms and skin uses.
What the research shows
| Use | What NCCIH reports |
|---|---|
| Mild or moderate depression | Better than placebo; similar to standard antidepressants |
| Severe depression or use past 12 weeks | Uncertain |
| Menopause hot flashes | Small number of studies suggest help |
| ADHD, IBS, OCD, PMS, quitting smoking | Not clearly shown to help |
NCCIH says many studies support St. John's wort for mild or moderate depression. A small number of studies also suggest it may help somatic symptom disorder, which involves intense anxiety about physical symptoms.
Depression needs professional care. If you think you are depressed, see a health care provider. Do not use St. John's wort instead of treatment, and seek help right away if you have thoughts of harming yourself.
Drug interactions: the most important warning
NCCIH says it has been clearly shown that St. John's wort can interact in dangerous, sometimes life-threatening ways with many medicines. It can weaken the effects of:
- Some antidepressants, including amitriptyline and bupropion
- Birth control pills
- Cyclosporine, used to prevent transplant rejection
- Some seizure drugs, including phenytoin and carbamazepine
- Some heart drugs, including digoxin and ivabradine
- Some HIV drugs, including indinavir and nevirapine
- Some cancer drugs, including irinotecan, imatinib and docetaxel
- Warfarin, a blood thinner
- Certain statins, including simvastatin
Taking it with certain antidepressants or other drugs that affect serotonin may lead to serious serotonin-related side effects. If you take any medicine, talk with your provider first.
Other safety points
- Short-term safety. For adults not taking any medicine, it appears safe for up to 12 weeks, and some studies suggest use for a year or more.
- Sun sensitivity. Large oral doses, or skin use, might cause severe skin reactions after sun exposure. NOW Foods warns larger amounts may contribute to skin reddening in strong sunlight or tanning beds.
- Side effects. Diarrhea, dizziness, trouble sleeping, restlessness and skin tingling.
- Pregnancy and breastfeeding. It may be unsafe in pregnancy because it may increase the risk of birth defects. Breastfed infants of mothers taking it can have colic, drowsiness and lethargy.
Reading a St. John's wort label
NOW Foods' St. John's Wort gives 300 mg of Hypericum perforatum herb extract per capsule, standardized to at least 0.3% hypericin. The label directs 1 capsule 3 times daily with food and says not to exceed 3 capsules daily unless directed by a health care professional.
- Standardization. Many extracts list 0.3% hypericin; compare products on the same basis.
- Dose per day. Capsules range widely in mg. Follow the label and do not exceed it.
- Blends. Mood blends may contain other herbs, adding more interaction risk.
- Medication check. NOW Foods tells users not to take it with any medication or medical condition without a physician's advice.
What to look for when you buy
St. John's wort extract, 0.3% hypericin
Best for: Adults on no medications whose doctor has okayed a trial for mild low mood
NOW Foods lists 300 mg of herb extract standardized to at least 0.3% hypericin per capsule, taken 3 times daily with food.
Watch out: Interacts with many medicines, including birth control and warfarin. Not for pregnancy. Do not exceed 3 capsules daily.
See options on AmazonSt. John's wort capsules, higher strength
Best for: Adults following specific advice from their provider
Higher-strength capsules reduce how many pills you take per day.
Watch out: Large amounts may raise sun sensitivity. Same interaction risks. Check the hypericin standardization.
See options on AmazonSt. John's wort liquid extract
Best for: People who prefer drops
Liquid extracts allow flexible dosing in water or tea.
Watch out: Strength is less standardized across brands. Same interaction and pregnancy cautions.
See options on AmazonQuestions people ask
- What supplements and medicines should not be taken with St. John's wort?
- Many medicines, including birth control pills, warfarin, some antidepressants, seizure, heart, HIV and cancer drugs, cyclosporine and simvastatin. Ask your provider about any medicine or supplement first.
- Does St. John's wort work for depression?
- NCCIH says it appears better than placebo and as effective as standard antidepressants for mild or moderate depression up to 12 weeks. It is uncertain for severe depression.
- Is St. John's wort a supplement?
- Yes, in the U.S. it is sold as a dietary supplement, which means it is not approved by the FDA before sale like a drug would be.
- Can St. John's wort make you sensitive to the sun?
- Large oral doses or skin use might cause severe skin reactions after sun exposure.
- When should I take St. John's wort?
- Follow the label. NOW Foods directs 1 capsule 3 times daily with food, no more than 3 a day without professional advice.
Sources
- St. John's Wort: Usefulness and Safety (nccih.nih.gov), National Center for Complementary and Integrative Health
- St. John's Wort 300 mg Veg Capsules (www.nowfoods.com/products/supplements/st-johns-wort-300-mg-veg-capsules), NOW Foods