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St John's wort - Hypericum perforatum

This information explains what St John's wort is used for, how it works, possible side effects and interactions with other medicines.

What dosage should I take?

St John's wort is sold in a variety of different forms. The dosages available vary depending on the form and brand that you buy.

It is most commonly sold as tablets and capsules. You can also get it as a tea, or as a liquid called a 'tincture', which you can take as drops in water.

"My mum used to send the [St John's wort] teabags as part of a care package. They did not stop me seeking help when I returned and I don't know if they helped but I felt like I was trying something."

All medicines carry levels of risk in different circumstances, and can affect people in different ways. There is no standard recommended dosage of St John's wort in the UK and it's not currently clear what dosage works best.

It's easiest to keep track of what dose you're taking if you take St John's wort in tablet or capsule form and if you stick to one particular brand. Be aware that if you buy a different type or brand, the dosage may be different or cause different side effects.

"I have to admit my experience of St John's wort has been a bit negative. As it's a herbal medicine, you're never too sure if you're taking the right dose."

If you are considering taking St John's wort, you may find it helpful to talk to your doctor or a pharmacist first to discuss what dosage would be best for you and check that taking St John's wort will not interact dangerously with any other medications you are taking.

Before deciding what dose to take, read the packaging carefully and consider:

  • how strong the product is – the packaging should give you an indication of this by describing the amount of hypericin or hypericum extract in the ingredients list or nutritional information section
  • how many times you should take the product each day – directions should be given on the packaging. Tablets and capsules typically range from 1-3 times a day, depending on their strength.

On the packaging of some products it might refer to the amount of St John's wort as 'aerial parts'. This just means the parts of the plant that grow above the ground.

"It's a good stop-gap solution to make you feel that you are doing something to take control of depression however I've found the knock on effects of missing a dose to be worse than that of SSRIs."

This information was published in January 2020. We will revise it in 2023.

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