Inositol may be important for PCOS women for at least three reasons:

* It may aid insulin action and thus reduce insulin resistance.
* It may help to relieve depression, which is common in polycystic ovary syndrome.
* It helps your liver to metabolize fat.

Inositol is a compound that has nine different forms. The most well-known and nutritionally active form is "myo-inositol", which most people simply refer to as "inositol". It is a necessary component of the membranes of your cells and is vital to many biological processes in your body. It is a precursor to a number of essential "signaling molecules" that instruct cells how to behave.

Some of inositol's signaling is related to activation of serotonin receptors, which could relieve depression and improve appetite balance. Serotonin is a brain chemical with several important functions in the body, including mood and appetite regulation.

Inositol is also a fat-solublizing agent that helps to transport fat from the liver. For those overweight PCOS women who may have a problem with fatty liver congestion, inositol can be helpful.

Although inositol is widely thought of as a member of the B-vitamin family, it is technically not a vitamin because the body can manufacture inositol and is not required to get it from the diet.

Where Does Inositol Come From?

Bacteria in your intestines convert the phytic acid found in plant fibers into inositol, so your body is able to manufacture its own supply of inositol. Phytic acid can be found in fruits, vegetables, legumes, whole grains and nuts.

You can also obtain dietary inositol from animal foods such as beef heart, beef liver and eggs.

Average dietary intake of inositol is about one gram daily. Dietary intake of inositol can influence the levels of inositol in the body and thus may influence biological activities. Inositol supplements may affect behavior and may have anti-depressant and anti-anxiety activities.

D-Chiro Inositol

Another naturally occurring form of inositol is d-chiro-inositol, which has been found to have activity against insulin resistance. However, d-chiro-inositol is not commercially available either as a drug or as a supplement.

It is found in legumes and especially in buckwheat. Consumption of buckwheat concentrate appears to reduce excessively high blood sugar levels and reduce the excretion of d-chiro-inositol in diabetic rats.(1)

D-Chiro Inositol and PCOS

You may have heard that d-chiro-inositol helps to treat polycystic ovarian syndrome. It is thought that it does this by improving insulin sensitivity.

Recent studies have suggested that women with PCOS may have insulin resistance and hyperinsulinemia due to a d-chiro inositol deficiency. D-chiro-inositol has been shown to influence the action of insulin. The amount of chiro-inositol in muscle has been shown to be lower in subjects with type 2 diabetes than in normal people.

A study from the Medical College of Virginia found that 1200 mg. of d-chiro-inositol daily had multiple beneficial effects in the treatment of 22 overweight PCOS women.(2) Not only did it improve the action of insulin, but 86% of the women ovulated during treatment with d-chiro-inositol compared to only 27% in the placebo group. Serum androgen (male hormone) and ovarian androgen production also decreased in the treatment group.

Another study showed similar results in lean PCOS women.(3)

However, there's one big problem: D-chiro-inositol is not commercially available, either as a drug or as a nutritional supplement. (side note, this is now available, you can google it and find it! But it's sorta expensive)

Inositol and PCOS

Since d-chiro inositol is not available, what about ordinary inositol, which is readily available as a nutritional supplement? A recent study suggests that common inositol may be helpful for PCOS and polycystic ovaries.(4)

In this study at the University of Perugia in Italy, 136 PCOS women took inositol (100 mg., twice daily) for 14 weeks. Another group of PCOS women took placebo pills.

The ovulation frequency was significantly higher in the treated group (23%) compared with the placebo (13%). The time in which the first ovulation occurred was significantly shorter (23.6 days) compared with 41.8 days for the placebo group. The number of patients failing to ovulate was higher in the placebo group.

The effect of inositol on follicular maturation was rapid. Also, significant weight loss (and leptin reduction) was recorded in the inositol group, whereas in the placebo group had an increase in weight.

This study suggests a beneficial effect of inositol in improving ovarian function in women with irregular cycles and polycystic ovaries.


There are no contraindications for inositol. Inositol supplementation is generally well tolerated. Gastrointestinal effects such as nausea or diarrhea are occasionally reported with high doses. No toxicity has been reported. (Well, I get that anyways with Metformin)

Due to a lack of long-term safety data, inositol should be avoided by pregnant women and nursing mothers. Also, one review article suggested that inositol may stimulate uterine contractions, although no research has demonstrated that inositol actually has this effect.

It's theoretically possible that inositol could worsen hypomanic or manic symptoms of bipolar disorder, so people with this condition should check with their doctor before using supplemental inositol.

Theoretically, high-dose inositol may increase the effects of anti-depressant selective serotonin reuptake inhibitors (SSRI drugs) such as fluoxetine sertraline, paroxetine, fluvoxamine and citalopram, and with 5-hydroxytryptamine receptor agonists, such as sumatriptan. If you are taking anti-depressant drugs, consult with your doctor before taking supplemental inositol.


According to the study we cited above, PCOS women appeared to get some benefit from a dose of only 200 mg. daily, which is a very moderate amount. Some doctors may recommend 500 mg. twice daily. In contrast, as much as 12 grams (12,000 mg.) has been used in studies to treat depression or panic attacks.

200 - 1,000 mg. per day for PCOS appears to be safe. A considerably higher dose may be appropriate in some situations, but consult with your physician as to how much more you should take. (I have seen other articles and studies where the amount calls for 2,000-4,000 mg. I suggest you do additional research and see what's best for you! )

Inositol is available either in capsules, tablets or in powder form. You can obtain high quality inositol from our PCOS Supplements Store.

(1) Kawa, JM et al, Buckwheat concentrate reduces serum glucose in streptozotocin-diabetic rats, J Agric Food Chem. 2003 Dec 3;51(25):7287-91.
(2) Nestler, JE et al, Ovulatory and metabolic effects of D-chiro-inositol in the polycystic ovary syndrome, Engl J Med. 1999 Apr 29;340(17):1314-20.
(3) Iuorno, MJ et al, Effects of d-chiro-inositol in lean women with the polycystic ovary syndrome, Endocr Pract. 2002 Nov-Dec;8(6):417-23.
(4) Gerli S et al, Effects of inositol on ovarian function and metabolic factors in women with PCOS: a randomized double blind placebo-controlled trial, Eur Rev Med Pharmacol Sci. 2003 Nov-Dec;7(6):151-9