Depression: Does hypericum (St John's wort) help?

Some St John’s wort products can relieve mild to moderate depression in the short term. They have not been proven to have the same effect in severe depression, though. Adverse effects are less common with St John’s wort products than they are with some other antidepressants. But there may be drug-drug interactions.

An estimated one out of six people suffer from depression at some point in their life. Depression is different from just being sad or feeling a bit moody or "blue". Typical signs of depression include feeling very low for at least two weeks and losing interest in things you usually enjoy. People who are depressed usually sleep badly, feel exhausted and have problems coping with everyday life. They lose their self-confidence and often withdraw from activities. Concentrating is difficult, and they have very negative thoughts about themselves.

Depression can be a single episode that lasts for weeks or months. Sometimes it will go away by itself, but often it will stay (chronic depression) or get worse. It is not uncommon for people to have recurring episodes of depression: many of those who have had depression in the past have it again later on in life. Depending on the number and severity of symptoms, depression is classified as mild, moderate or severe. Severe depression is a very serious illness, and people with severe depression are at risk of suicide. Click here to find out about the possible symptoms of depression.

Treatment options for depression

Depression can be treated with psychological therapies and/or drugs called antidepressants. People with milder depression often use herbal remedies, including ones with St John’s wort extracts in them. The Latin name for St John’s wort (hypericum perforatum) is also often used for St John’s wort products.

As with most herbal medicines (phytopharmaceuticals), there is a wide variety of products made from hypericum on the market, with very different doses and ingredients. So there is no guarantee that the hypericum products you can buy have the same effect as the extracts that have been tested in trials. A lot of products only have a very small dose of hypericum in them.

The regulations in Germany changed at the beginning of April 2009, so that some hypericum products are now only available on prescription. This only affects those for moderate depression though. The hypericum products that are used for other things, such as mild depression, are still available without a prescription.

You can read more about complementary (or "alternative") products like St John’s wort or hypericum in our fact sheet.

Research on the effect of hypericum

A group of researchers from the Cochrane Collaboration looked for trials that tested hypericum products to find out whether they can relieve depression in adults, and how they compare to other drugs for depression. They included a total of 29 trials in their analysis, involving about 5,500 participants: 12 trials compared hypericum with a dummy treatment (placebo), 11 trials compared it with other antidepressants, and 6 trials compared it with both another antidepressant and a placebo. The trials lasted between 4 and 12 weeks and tested very different hypericum products in various doses. Most of the people in the trials had mild or moderate depression, and some of them had severe depression. About 7 out of 10 of the people in the trials were women (70%).

The results for people with mild to moderate depression

The hypericum extracts used in the trials were found to relieve mild to moderate depression better than placebo treatment did. Trials that compared hypericum with other antidepressants showed a similar effect for both treatments. They did not look at all of the antidepressants that are commonly used nowadays, though.

One serious problem with the trials is that the participants were only monitored for a few weeks. But depression often lasts longer or comes back after a while. So an important question for people with depression is whether hypericum products help in the longer term or can prevent further episodes of depression. The research that has been done so far cannot answer these questions.

Also, this may not be true for every hypericum product because the many products you can buy have different ingredients. In most of the trials the participants used doses between 500 mg and 1,200 mg per day. But there was not enough information from the trials to say how the different extracts compare with each other or what the best dose is.

The results for people with major depression

The researchers did not find any evidence that hypericum helps in severe depression. Severe depression is a serious illness, and it is unlikely that self-treatment with hypericum alone will help. Click here to find out more about other treatment options for depression, including various other antidepressants or psychological treatments.

Adverse effects and interactions with other drugs

Hypericum products can cause adverse effects such as nausea, minor skin irritations, sensitivity to light (photosensitivity) and headaches. Some people are allergic to these products too. But they are somewhat less likely to cause adverse effects than other antidepressants, such as SSRIs (selective serotonin reuptake inhibitors) or tricyclic antidepressants.

The biggest safety concern with hypericum products, however, is that they might interact with other medicines. In other words, taking hypericum products at the same time as other medicines could increase or reduce the effect of those drugs. In particular, hypericum might reduce the effect of drugs which slow down blood clotting (like warfarin, or “Marcumar”), which could increase the risk of blood clots. Hypericum also weakens the effect of drugs that influence the immune system (like cyclosporine, which suppresses the immune system). And there is some evidence that it can stop the contraceptive pill from working properly.

Because taking herbal products like hypericum together with other medicines can lead to problems, people who are taking several medicines should be aware of possible interactions between them. If you are taking other medications, it is also important that your doctor knows if you are using, or are planning to use, hypericum.


Author: German Institute for Quality and Efficiency in Health Care (IQWiG)

© IQWiG (Institute for Quality and Efficiency in Health Care)