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 Question mark: This treatment has not been properly researched. It is not possible to say whether they are useful or not.

What is it?

Selenium is an essential trace element present in many foods.

How does it work?

Low levels of selenium in the diet may have an effect on mood. Some countries have a low level of selenium in the soil. This in turn affects the amount of selenium available in food. It has been proposed that people living in these countries may need selenium supplements. The countries affected include New Zealand, United Kingdom and parts of China, Scandinavia and the United States. Australian soil is not deficient and the average Australian diet contains adequate selenium.

Is it effective?

A study in the United Kingdom found that when people without depression were given selenium supplements their mood improved. Some of these people may have had a low-level selenium deficiency. A larger, more recent study gave healthy participants different doses of selenium or a placebo (dummy pill). After six months, they found no differences in mood between those who received selenium and those who did not.

Selenium has not been tested specifically with people who are depressed.

Are there any disadvantages?

Selenium can be toxic in high doses. If you would like to take selenium supplements, ask your doctor or pharmacist what dose is right for you, and ask it if might interfere with other medications or supplements you are taking. Make sure to talk with your doctor if your symptoms worsen or new ones develop.

Where do you get it?

Selenium supplements are available from health food shops.


Selenium supplements may be helpful for people with a deficiency. But, given the lack of evidence on selenium, it cannot be recommended as a treatment for depression.  

Key references

  • Benton D, Cook R. The impact of selenium supplementation on mood. Biological Psychiatry 1991; 29: 1092-1098.
  • Rayman M, Thompson A, Warren-Perry M, Galassini R, Catterick J, Hall E, et al. Impact of selenium on mood and quality of life: a randomized, controlled trial. Biol Psychiatry. 2006 Jan 15;59(2):147-54.

Last reviewed and updated: 1 December 2016