Can I take Folic acid and St John's wort together?

Why this happens

Folic acid is a water-soluble B vitamin, while St John's wort is an herbal remedy primarily used for low mood. They are processed by different pathways in the body and do not interfere with each other's absorption, metabolism, or effectiveness.

What you should do

You can continue to take both as directed. However, always inform your doctor or pharmacist if you are taking St John's wort, as it interacts with many other prescription medicines (such as the contraceptive pill, blood thinners, and antidepressants).

Important precautions

Vitamin B12 deficiency (Pernicious Anaemia)

Folic acid can mask the symptoms of vitamin B12 deficiency. If you have B12 deficiency, taking folic acid alone can allow serious nerve damage to progress even though your blood count appears normal. Your doctor must ensure your B12 levels are checked before or during treatment.

Depression and Mental Health

Like other antidepressants, St John's wort may increase the risk of suicidal thoughts or self-harm, particularly when first starting treatment. Seek immediate medical help if your mood worsens.

Drug Interactions

St John's wort significantly reduces the effectiveness of many essential medicines, including the contraceptive pill, blood thinners (warfarin), epilepsy medications, and organ transplant drugs. Do not start it without a pharmacist checking your current medications.

Serotonin Syndrome

Taking St John's wort with other antidepressants or triptans (for migraine) can cause serotonin syndrome, a potentially life-threatening condition involving high fever, agitation, and muscle rigidity.

Photosensitivity

St John's wort can make your skin significantly more sensitive to sunlight, leading to severe sunburn or skin reactions even with limited exposure.

Food and drink warnings

Alcohol

It is best to avoid or strictly limit alcohol while taking folic acid. Alcohol interferes with the way your body absorbs and uses folic acid, which can make the treatment less effective. Chronic alcohol consumption is a common cause of folate deficiency.

It is best to avoid or strictly limit alcohol while taking St John's wort. Combining them can increase drowsiness and dizziness, and may worsen the side effects of the herbal remedy.

Caffeine (Coffee, Tea, Energy Drinks)

St John's wort can increase your sensitivity to caffeine. This may lead to feelings of anxiety, a racing heart, or difficulty sleeping.

Foods high in Tyramine (Aged cheeses, cured meats, soy sauce, marmite)

Although the risk is low, St John's wort may interact with tyramine-rich foods, potentially causing a sudden increase in blood pressure. It is sensible to consume these foods in moderation.

Using other medicines

Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.