Inositol is a vitamin-like substance that is present in all animal tissues, although the highest concentrations are found in the heart and brain. It also is possible to create inositol synthetically in a laboratory.

The role of inositol
Inositol is part of all cell membranes. It is used in the functioning of muscles and nerves, and helps the liver process fats.

Some research shows possible involvement of inositol in depression and other mood disorders. People who are depressed seem to have lower levels of inositol in their spinal fluid; inositol also participates in the action of serotonin, a neurotransmitter important to a person’s sense of well-being. However, not all studies have proven that increasing inositol intake can help depressed individuals, and some studies show that inositol may initially help depressed people but, with time, has no effect.

Other studies have looked at the possible relationship of inositol to bipolar disorder, panic disorder, bulimia nervosa, and obsessive-compulsive disorder.

Two double-blind studies showed that inositol may have a positive impact on women with polycystic ovarian syndrome, lessening the infertility and weight gain associated with this condition. To date, no positive impact exists for women suffering from premenstrual dysphoric disorder.

In one study, people given 12 grams (g) of inositol/day had fewer and less severe panic attacks. In another study, inositol was at least as effective as the medication Luvox® in treating panic disorder.

Inositol is possibly, or likely, ineffective for schizophrenia, Alzheimer’s disease, autism, and diabetic neuropathy.

Insufficient evidence exists on inositol’s effect on attention-deficit hyperactive disorder, cancer, problems with fat metabolism, high cholesterol, and insomnia.

Doses used in scientific research include:

Diet information
Inositol is not considered an essential nutrient at this time, which means that it is believed that most of us do not need to worry about getting enough from our diet.

However, certain foods do contain phytic acid, which releases inositol once it is acted on by bacteria in the intestines. These foods include:

Side effects of taking supplemental inositol
No serious side effects are reported in people taking up to 18 g/day, but no long-term safety studies have taken place. Although inositol is sometimes recommended for bipolar disorder, some proof shows that it may trigger manic episodes in some people. Therefore, people with bipolar disorder should never take inositol unless they are under a physician’s supervision.

Some people report nausea, flatulence, lethargy, headache, and dizziness when taking inositol.

It appears that inositol may lessen the absorption of calcium, iron, magnesium, zinc, and copper in the stomach.

References and recommended readings
Clements RS, Darnell B. Myo-inositol content of common foods: development of a high-myo-inositol diet. Am J Clin Nutr [serial online]. 1980;33:1954-1967. Available at: