Inositol

What does it do?

Inositol is part of the vitamin B-complex. It is required for proper formation of cell membranes.

Inositol affects nerve transmission and helps in transporting fats within the body. Inositol differs from inositol hexaniacinate, a form of vitamin B3.

Where is it found?

Nuts, beans, wheat and wheat bran, cantaloupe, and oranges are excellent sources of inositol. Most dietary inositol is in the form of phytate.

Inositol has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating	Health Concerns
	Anxiety Depression Obsessive-compulsive disorder
	Bipolar disorder/manic depression Diabetes
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Rating

Health Concerns

Anxiety

Depression

Obsessive-compulsive disorder

Bipolar disorder/manic depression

Diabetes

Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars

Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star

For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Who is likely to be deficient?

Clear deficiency of inositol has not been reported, although people with diabetes have increased excretion and may benefit from inositol supplementation.

How much is usually taken?

Most people do not need to take inositol. In addition, the small amounts commonly found in multivitamin supplements are probably unnecessary and ineffective. Doctors sometimes suggest 500 mg twice per day. For depression, anxiety, and obsessive-compulsive disorder, 12–18 grams per day has been shown to be effective in double-blind trials.¹ ² ³ ⁴

Are there any side effects or interactions?

Toxicity has not been reported, although people with chronic renal failure show elevated levels and should not take inositol, except under medical supervision.

Large amounts of phytate, the common dietary form of inositol, reduce the absorption of calcium, iron, and zinc. However, supplemental inositol does not have this effect.

One review article suggested that inositol may stimulate uterine contractions.⁵ While no research has demonstrated that inositol actually has this effect, women who are or could become pregnant should consult a doctor before taking inositol.

Are there any drug interactions?
Certain medicines may interact with inositol. Refer to drug interactions for a list of those medicines.

References

1. Levine J, Barak Y, Gonzalves M, et al. Double-blind, controlled trial of inositol treatment of depression. Am J Psychiatry 1995;152:792–4.

2. Levine J, Barak Y, Kofman O, Belmaker RH. Follow-up and relapse analysis of an inositol study of depression. Isr J Psychiatry Relat Sci 1995;32:14–21.

3. Benjamin J, Levine J, Fux M, et al. Double-blind, placebo-controlled, crossover trial of inositol treatment for panic disorder. Am J Psychiatry 1995;152:1084–6.

4. Fux M, Levine J, Aviv A, Belmaker RH. Inositol treatment of obsessive-compulsive disorder. Am J Psychiatry 1996;153:1219–21.

5. Colodny L, Hoffman RL. Inositol—Clinical applications for exogenous use. Altern Med Rev 1998;3:432–47.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires March 2005.