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Can I take St John's wort and Vitamin B12 together?

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There is no known interaction between St John's wort and Vitamin B12. It is generally considered safe to take these two together.

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Varför detta händer

St John's wort is known to affect the liver enzymes (specifically CYP3A4) and a transport protein (P-glycoprotein) that clear many medicines from the body. However, Vitamin B12 (cobalamin) is a water-soluble vitamin that is absorbed and processed by the body through different pathways that are not affected by these enzymes.

You can continue to take both as directed. However, if you are taking St John's wort, you should always check with a pharmacist or doctor before starting any other new medications, as it interacts with many prescription drugs (such as the contraceptive pill, blood thinners, and antidepressants).

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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.

Alkohol

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

It is best to avoid or strictly limit alcohol while taking Vitamin B12. Heavy alcohol consumption can interfere with the body's ability to absorb Vitamin B12 from the gut and can reduce the amount of the vitamin stored in the liver.

Caffeine (Coffee, Tea, Energy Drinks)

St John's wort can sometimes increase sensitivity to caffeine, leading to feelings of restlessness, anxiety, or a racing heart. Monitor your intake if you feel jittery.

Foods high in Tyramine (e.g., aged cheeses, cured meats, soy sauce, marmite, overripe fruit)

While less common than with older prescription antidepressants, St John's wort can potentially interact with tyramine-rich foods, leading to a sudden, dangerous increase in blood pressure (hypertensive crisis). You should consume these foods in moderation.

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Taking multiple medicines? Our Interaktionskontroll för läkemedel 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.

Ansvarsfriskrivning

Denna information är endast avsedd för allmän utbildning och bör inte användas som en ersättning för professionell medicinsk rådgivning. Rådfråga alltid din läkare, apotekare eller annan kvalificerad vårdpersonal innan du fattar beslut om dina mediciner. Individuella omständigheter kan variera, och endast en vårdpersonal som känner till din medicinska historia kan ge personlig vägledning.

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Artikelhistorik

Informationen på denna sida är skriven och granskad av kvalificerade kliniker.

  • 25 jan 2026 | Ursprungligen publicerad
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