St John’s Wort

What is St John’s Wort?

St John’s wort (Hypericum perforatum) is a flowering plant that has been used medicinally for centuries and is classified as an herbal supplement. It is most commonly used as a natural treatment for mild to moderate depression and mood disorders. The supplement is available over-the-counter in various forms including capsules, tablets, teas, and liquid extracts.

Uses

St John’s wort is primarily used for several mental health and wellness applications:

Depression: The most well-documented use is for treating mild to moderate depression, where it may help improve mood and reduce depressive symptoms.

Anxiety: Some people use St John’s wort to help manage anxiety symptoms and promote emotional well-being.

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Seasonal Affective Disorder (SAD): It is sometimes used to address mood changes related to seasonal light deprivation during winter months.

Sleep disorders: The herb may help with sleep quality and is occasionally used for mild insomnia related to mood issues.

Wound healing: Topical preparations have traditionally been used for minor cuts, burns, and skin irritations, though this is less common today.

How it works

St John’s wort contains several active compounds, including hypericin and hyperforin, which are believed to affect neurotransmitter levels in the brain. These compounds may inhibit the reuptake of serotonin, dopamine, and norepinephrine – brain chemicals that regulate mood – similar to how some prescription antidepressants work. The exact mechanisms are still being studied, but the herb appears to influence multiple pathways involved in mood regulation.

Side effects

Common side effects include:

• Increased sensitivity to sunlight (photosensitivity)
• Dry mouth
• Dizziness
• Digestive upset or nausea
• Fatigue or restlessness
• Headache
• Sleep disturbances
• Skin reactions or rash

Serious side effects to watch for:

• Severe allergic reactions
• Manic episodes in people with bipolar disorder
• Severe sunburn even with minimal sun exposure
• Signs of serotonin syndrome when combined with other medications

Warnings and precautions

Pregnancy and breastfeeding: St John’s wort should be avoided during pregnancy and breastfeeding due to insufficient safety data and potential risks to the developing baby.

Mental health conditions: People with bipolar disorder, schizophrenia, or severe depression should avoid St John’s wort as it may trigger manic episodes or interfere with proper treatment.

Surgery: The supplement should be discontinued at least two weeks before scheduled surgery due to potential interactions with anesthesia and effects on neurotransmitters.

Sun sensitivity: Users must be extremely careful about sun exposure and should use protective clothing and sunscreen, as the herb significantly increases photosensitivity.

Medication interactions: Due to extensive drug interactions, anyone taking prescription medications should consult a healthcare provider before using St John’s wort.

Interactions

St John’s wort has numerous significant drug interactions due to its effects on liver enzymes that metabolize medications:

Antidepressants: Can cause dangerous serotonin syndrome when combined with SSRIs, SNRIs, or MAO inhibitors.

Birth control pills: May reduce contraceptive effectiveness, leading to breakthrough bleeding or unwanted pregnancy.

Blood thinners: Can decrease the effectiveness of warfarin and other anticoagulants, increasing clotting risk.

Heart medications: May reduce levels of digoxin and other cardiac drugs, potentially causing heart rhythm problems.

Immunosuppressants: Can lower levels of cyclosporine and tacrolimus, increasing risk of organ rejection in transplant patients.

Cancer medications: May interfere with chemotherapy drugs like imatinib and irinotecan, reducing their effectiveness.

HIV medications: Can significantly reduce levels of protease inhibitors and other HIV drugs, leading to treatment failure.

Seizure medications: May decrease levels of anticonvulsants, potentially triggering seizures.

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Evidence summary

The scientific evidence for St John’s wort shows moderate evidence for treating mild to moderate depression, with several clinical trials demonstrating effectiveness comparable to some prescription antidepressants for these conditions. However, there is insufficient evidence for severe depression, where prescription medications remain the standard of care. Evidence for anxiety and seasonal affective disorder shows limited evidence, with more research needed to establish effectiveness. For detailed safety and efficacy information, visit supplement.ge for a comprehensive safety profile.

Dosage

Typical adult dosages range from 300 to 900 mg daily, usually divided into two or three doses with meals. Standardized extracts containing 0.3% hypericin and 3-5% hyperforin are commonly used. Some studies have used specific doses of 300 mg three times daily. However, appropriate dosage varies based on the specific product concentration and individual factors, so dosage should always be determined by a qualified healthcare provider who can assess individual needs and monitor for interactions.

Sources: FDA DailyMed drug labels (public domain), BNF, WHO Essential Medicines List. This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting or stopping any medication.

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