Pinitol and PCOS

"D-chiro inositol" was the object of much excitement a few years ago in PCOS circles because a study showed it improved ovulation, reduced testosterone levels and insulin resistance.

Pinitol is another form of inositol that is very similar to D-chiro inositol, and is converted into d-chiro inositol in the body. The chemical name of pinitol is "3-O-methyl-D-chiro-inositol". d-Pinitol is featured in our online store.

The page introduces you to pinitol and describes its relevance to polycystic ovary syndrome.


D-chiro-inositol, a relative of common inositol (a B vitamin), is found in small concentrations in the human body and in some foods.

It is a compound that has been reported to affect the action of insulin.

There is evidence that the insulin resistance seen in women with PCOS is due in part to a deficiency of D-chiro-inositol or to a defect in its utilization in the tissues.(1,2) If these abnormalities can be reversed by supplementation with D-chiro-inositol, then this compound might be beneficial for women with PCOS.

To test that possibility, 44 obese women with PCOS were randomly assigned to receive, in double-blind fashion, D-chiro-inositol (1,200 mg once a day) or placebo for eight weeks.

Supplementation with D-chiro-inositol resulted in an improvement in insulin resistance and a 55% reduction in testosterone levels compared to the placebo group.

Significantly more women ovulated in the D-chiro-inositol group than in the placebo group (86% vs. 27%). D-chiro-inositol supplementation decreased testosterone levels and improved ovulatory function, presumably by enhancing the action of insulin.(2)

What Is Pinitol?

Pinitol (3-O-methyl- D-chiro-inositol) is an inositol compound with a chemical structure and biochemical actions similar to D-chiro-inositol.

Pinitol is conveniently available as a nutritional supplement.

Pinitol occurs naturally in several different foods, including legumes and citrus fruits.

Like D-chiro-inositol, pinitol appears to influence the action of insulin.(3) Moreover, pinitol is probably converted to D-chiro-inositol in the body, as demonstrated by a 14-fold increase in the levels of D-chiro-inositol after administration of pinitol to diabetic patients at a dose of 20 mg per kg of body weight per day for four weeks.(3)

In a double-blind study of patients with type 2 diabetes, administration of 600 mg of pinitol twice a day for three months reduced blood glucose concentration by 19.3%, decreased hemoglobin A1c concentration by 12.4%, and significantly improved insulin resistance.(4)

In a shorter-term double-blind study, administration of pinitol at a dose of 20 mg per kg of body weight per day for four weeks decreased the mean fasting plasma glucose concentration by 5.3%.(5)

Pinitol has not been studied as a treatment for PCOS. However, because an estimated 33% of orally administered pinitol is converted in the body to D-chiro-inositol,(5) and because it appears to have biochemical effects similar to those of D-chiro-inositol, pinitol might be beneficial for women with PCOS.

Safety and Interactions

There are no contraindications for pinitol. No toxicity has been reported.

Due to a lack of long-term safety data, pinitol should be avoided by pregnant women and nursing mothers.

If you are taking anti-depressant drugs, consult with your doctor before taking supplemental pinitol.

How Much Should You Take?

According to two of the studies we cited above, a dose of 1,200 mg of D-chiro inositol daily appeared to be effective.

The effective amount of pinitol isn't entirely clear. Since not all of the pinitol will convert into D-chiro inositol, we can assume a dose of at least 1,200 mg. would be needed for effect.

Where Can You Get It?

High quality pinitol in 600 milligram capsules (combined with chromium and vitamin D) is available from our online PCOS Supplements Store.

Click here for article footnotes.

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