Can St. John’s wort products help?

Photo of a woman sitting by a tree (PantherMedia / Dmitrii Kiselev)

Some St. John’s wort products can relieve mild to moderate depression in the short term. They haven't been proven to have the same effect in severe depression, though. Side effects are less common with St. John’s wort products than they are with some other antidepressants. But interactions with other drugs can occur.

Depression isn't the same as just feeling sad or down. The typical signs of depression include feeling very down for at least two weeks, along with a general lack of interest or motivation. People who are depressed usually sleep poorly, feel exhausted and have problems coping in everyday life. They lose their self-confidence, have a very negative self-image and often become withdrawn. They also have difficulty concentrating. Depression can be treated with psychological treatment and/or medication (antidepressants).

Treating depression with St. John's wort products

People with milder cases of depression often use herbal remedies with St. John's wort extracts in them. Some products that contain St. John's wort use the Latin name for it: Hypericum perforatum, or simply hypericum.

As with most herbal medicines (phytopharmaceuticals), there are many different St. John's wort products on the market, with very different doses and ingredients. A lot of these products only have a very small dose of hypericum in them. This means that different products may have different effects, and won't necessarily work like the products tested in the studies did.

St. John’s wort products for moderate depression have to be prescribed by a doctor. But no prescription is needed for products to treat mild depressive mood disorder.

Research on the effectiveness of St. John's wort

A group of researchers analyzed a total of 35 studies involving nearly 7,000 participants. They wanted to find out whether St. John's wort products can relieve the symptoms of depression in adults, and how they compare to other medications. The studies lasted at least four weeks and tested a wide range of St. John's wort products. In most of these studies the participants used St. John's wort at doses of between 500 mg and 1,200 mg per day. The study participants had mild to moderate depression. The majority of them were women.

Effectiveness in mild to moderate depression

The St. John's wort products used in the studies were found to relieve mild to moderate depression better than the placebo treatment did. Studies that compared St. John's wort with other antidepressants showed that the treatments were similarly effective.

Only few of the studies lasted more than eight weeks. But depression often lasts longer than that or comes back after a while. There isn't enough research on whether St. John's wort products are effective over the long term or can prevent further episodes of depression.

The researchers found no evidence that St. John's wort helps in severe depression. Severe depression is a very serious disease and should not be treated with St. John's wort alone.

Side effects and interactions with other medications

St. John's wort products can cause side effects such as nausea, minor skin irritations, sensitivity to light (photosensitivity) and headaches. They may trigger allergic reactions too. But the side effects are somewhat less common than those of other antidepressants.

Interactions with medications may occur when St. John's wort products are used – that means that they could increase or decrease the effect of other medications taken at the same time. For instance, St. John's wort reduces the effect of medicines that slow down blood clotting or suppress the body's immune system. And there's some evidence that it can make birth control pills less reliable.

Like conventional medicines, plant-based medicines such as St. John's wort may cause problems when used together with other medications. So it's important to be aware of possible interactions when taking more than one medication – and to not take over-the-counter medicine without consulting your doctor.