Our rating
2 smilies: This treatment is useful. It is supported by scientific evidence as effective, but the evidence is not as strong.

What is it?

Omega-3 is a type of polyunsaturated fatty acid. There are different types of omega-3 fatty acids. These are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is found mostly in walnuts, some seeds, and some oils. EPA and DHA are found in oily fish and eggs. ALA is converted into EPA and DHA by the body.

How does it work?

Omega-3 and depression have been linked in the following ways.

  • Some people with depression have lower levels of omega-3 in their red blood cells. This has led to the belief that low levels of omega-3 are linked with depression.
  • Some people believe depression is caused by inflammation. Omega-3 may reduce inflammation.
  • Countries with high fish consumption have lower reported rates of depression.

Is it effective?

A meta-analysis of data from 11 trials found that Omega-3 helped reduce depression symptoms. Omega-3 appeared to be more beneficial to people who were taking antidepressants.

Are there any disadvantages?

Some supplements can be harmful or ineffective if you take the wrong dose. Talk to your health care professional if you are thinking of taking supplements.

Where do you get it?

Omega-3 supplements are available at supermarkets, health food shops and pharmacies. Vegetarian varieties are also available.

Fish oil supplements may also contain omega-3 fatty acids but the amount will vary. It is important to check the label for omega-3. Common complaints from fish oil supplements include bloating, gas, belching, nausea, bad breath and/or loose stools.


There is evidence to suggest omega-3 helps depression. It appears to have stronger effects in people who are also taking antidepressants.

Key references

  • Grosso G, Pajak A, Marventano S, Castellano S, Galvano F, Bucolo C, et al. Role of omega-3 fatty acids in the treatment of depressive disorders: A comprehensive meta-analysis of randomized clinical trials. PLoS One; 2014: e96905.

Last reviewed and updated: 26 March 2015