Our rating
No smiley: On the available evidence, this treatment does not seem to be effective.


The rating system

  • 3 smiliesThese treatments are very useful. They are strongly supported as effective by scientific evidence.
  • 2 smiliesThese treatments are useful. They are supported by scientific evidence as effective, but the evidence is not as strong.
  • 1 smileyThese treatments are promising and may be useful. They have some evidence to support them, but more evidence is needed to be sure they work.
  • No smiley On the available evidence, these treatments do not seem to be effective.
  • Question markThese treatments have not been properly researched. It is not possible to say whether they are useful or not.
  • Exclamation MarkSafety or other concerns have been raised for the use of these treatments.

What is it?

Inositol is a sugar that is similar to glucose. It is found naturally in the body. It is in many foods such as meat, fruits and whole-grain cereals.

How does it work?

Some people with depression have lower levels of inositol in their brain and spinal fluid. It is suggested that increased inositol may improve mood.

Inositol plays a role in the chemical-messaging system in the brain and may help depression by helping brain cells communicate better. 

Is it effective?

There are some small studies on inositol and depression. Reviews of multiple studies have found that inositol was no more effective than taking a dummy pill (placebo) in treating depression. Inositol was also not effective when taken in addition to anti-depressant medication (compared to anti-depressant medication without inositol).

Overall, there is very little scientific evidence on inositol for the treatment of depression. More studies of better quality are needed. 

Are there any disadvantages?

No side effects have been reported in the studies of inositol and depression, however, these studies may not have looked for negative effects. Dietary supplements, including inositol, may have negative interactions with prescribed medications or other supplements. They should always be taken under the supervision of a health care professional.

Where do you get it?

Inositol is available as a dietary supplement. It can be purchased at some health food shops or over the internet.


Given the lack of evidence on inositol for depression, it cannot be recommended.

Key references

  • Firth J, Teasdale SB, Allott K, Siskind D, Marx W, Cotter J, et al. The efficacy and safety of nutrient supplements in the treatment of mental disorders: a meta-review of meta-analyses of randomized controlled trials. World Psychiatry: Official Journal of the World Psychiatric Association (WPA). 2019; 18(3):308-24.
  • Mukai T, Kishi T, Matsuda Y, Iwata N. A meta-analysis of inositol for depression and anxiety disorders. Human Psychopharmacology. 2014; 29(1):55-63.
  • Taylor MJ, Wilder H, Bhagwagar Z, Geddes J. Inositol for depressive disorders. (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Published by John Wiley & Sons, Ltd.

Last reviewed and updated: 7 August 2023