Inositol: A Promising Treatment Option For PCOS

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One of the most widely studied dietary supplements in the PCOS population is inositol. And with good reason: both Myo (MYO) and d-Chiro-inositol (DCI) inositol types have been shown to improve many of the metabolic and reproductive aspects of PCOS. These benefits include improvements to cholesterol, insulin, androgens and weight. Women who take inositol report fewer cravings. Best of all, MYO has been shown to boost fertility by improving egg quality and restoring menstrual regularity and well as reduce the risk for gestational diabetes.

While both MYO and DCI types offer many benefits to women with PCOS, new research now shows that it’s the combination of the two types, in the body’s natural ratio that shows the most benefit.

What is Inositol?

Inositol is a member of the B-vitamins and a component of the cell membrane. Inositol is found in foods such as fruits, beans, grains, and nuts and is also made by the body. While there are nine types of inositol, it’s MYO and DCI that have shown the best benefits in PCOS. That’s because it's believed that women with PCOS may have a defect in the body’s ability to use MYO and DCI, contributing to insulin resistance. MYO and DCI work as secondary messengers relaying signals involved in insulin regulation.

Benefits of Myo and d-Chiro Inositol Combined

MYO and DCI are separate molecules that work differently in the body. DCI is made from MYO upon demand.  The body maintains a normal plasma MYO to DCI ratio of 40:1.

The ratio of MYO to DCI in follicular fluid is much higher- 100:1. Follicles with high-quality oocytes have a much higher concentration of MYO.

An imbalance in the normal MYO to DCI ratio can affect egg quality. When DCI alone was administered at high dosages (600-2400 mg daily) it was found to negatively affect oocyte quality and ovarian response.

What’s more, the higher the dose of DCI (and the more imbalanced the ratio of MYO to DCI), the worse the oocyte quality and ovarian response became.

MYO has been well documented to be superior to DCI in improving insulin resistance, egg quality and reducing the risk for gestational diabetes in women with PCOS. However, when MYO is combined with DCI in the optimal ratio, the best results are seen.

In a study published in the journal of Archives of Gynecology and Obstetrics, women with PCOS undergoing IVF were treated with a combination of MYO and DCI in the physiologic ratio of 40:1 or 500 mg of DCI alone. The combined therapy was able to improve oocyte and embryo quality, as well as pregnancy rates, showing that MYO plays a crucial role in the ovary in PCOS women and the benefits of MYO and DCI in the optimal ratio.

In another study published this year in the European Review for Medical and Pharmacological Sciences, overweight women with PCOS received MYO and DCI or MYO alone for six months.

At the end of the treatment, the combined supplementation with MYO and DCI was more effective at reducing metabolic parameters compared to the MYO group. The authors concluded that “the combined administration of MI and DCI in physiological plasma ratio (40:1) should be considered as the first-line approach in PCOS.

What to know about taking Inositol?

It’s recommended that women with PCOS take a combined amount of MYO (2-4 grams) and DCI (50-100mg) in the physiologic ratio of 40:1.

Generally, MYO and DCI are well tolerated but may cause low blood sugar, especially if taking medications or other supplements that lower blood sugar. As always, check with your physician before starting inositol.


Costantino D, Minozzi G, Minozzi E, Guaraldi C. Metabolic and hormonal effects of myoinositol in women with polycystic ovary syndrome: a double-blind trial. Europ review  med pharmacol sci. 2009;13(2):105-110.

Unfer V, Carlomagno G, Rizzo P, Raffone E, Roseff S. Myo-inositol rather than D-chiro-inositol is able to improve oocyte quality in intracytoplasmic sperm injection cycles. A prospective, controlled, randomized trial. Europ review  med pharmacol sci. 2011;15(4):452-457.

Le Donne M, Alibrandi A, Giarrusso R, Lo Monaco I, Muraca U. [Diet, metformin and inositol in overweight and obese women with polycystic ovary syndrome: effects on body composition]. Minerva ginecologica. 2012;64(1):23-29.

Venturella R, Mocciaro R, De Trana E, D'Alessandro P, Morelli M, Zullo F. [Assessment of the modification of the clinical, endocrinal and metabolical profile of patients with PCOS syndrome treated with myo-inositol]. Minerva ginecologica. 2012;64(3):239-243.

Genazzani AD, Prati A, Santagni S, et al. Differential insulin response to myo-inositol administration in obese polycystic ovary syndrome patients. Gynecol Endocrinol. 2012;28(12):969-973.

Gerli S, Papaleo E, Ferrari A, Di Renzo GC. Randomized, double blind placebo-controlled trial: effects of myo-inositol on ovarian function and metabolic factors in women with PCOS. Europ rev med pharmacol sci. 2007;11(5):347-354.

Raffone E, Rizzo P, Benedetto V. Insulin sensitiser agents alone and in co-treatment with r-FSH for ovulation induction in PCOS women. Gynecol Endocrinol. 2010;26(4):275-280.

Galazis N, Galazi M, Atiomo W. d-Chiro-inositol and its significance in polycystic ovary syndrome: a systematic review. Gynecol Endocrinol. 2011;27(4):256-62

Papaleo, E., Unfer, V., Baillargeon, J.P., et al. (2007). Myo-inositol in patients with polycystic ovary syndrome: A novel method for ovulation induction. Gynecological Endocrinology,23 (12): 700-703.

D 'Anna R, Di Benedetto V, Rizzo P, et al. Myo-inositol may prevent gestational diabetes in PCOS women. Gynecol Endocrinol. 2012;28(6):440-442.

Isabella R, Raffone E. Does ovary need D-chiro-inositol? J Ovarian Res. 2012 May 15;5(1):14.

Dinicola S1, Chiu TT, Unfer V, Carlomagno G, Bizzarri M. The rationale of the myoinositol and D-chiro-inositol combined treatment for polycystic ovary syndrome. J Clin Pharmacol. 2014 Oct;54(10):1079-92.

Nordio M, Proietti E. The combined therapy with myoinositol and D-chiro-inositol reduces the risk of metabolic disease in PCOS overweight patients compared to myoinositol supplementation alone. Eur Rev Med Pharmacol Sci. 2012 May;16(5):575-81.

Colazingari S, Treglia M, Najjar R, Bevilacqua A. The combined therapy myoinositol plus D-chiro-inositol, rather than D-chiro-inositol, is able to improve IVF outcomes: results from a randomized controlled trial. Arch Gynecol Obstet. 2013 Dec;288(6):1405-11.

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