4 Things to Know About Taking Inositol for PCOS

Inositol capsule
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Inositol is showing promise as a primary treatment for all women with PCOS due to its ability to improve metabolic and reproductive aspects. Here’s what to know.

Inositols Are Secondary Messengers

Inositols such as myo and d-chiro inositol (DCI), are members 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.

Myo and DCI work as secondary messengers relaying signals involved in insulin regulation. It's believed that women with PCOS may have a defect in the body’s ability to convert MYO into DCI, contributing to insulin resistance and infertility. Supplementing with inositol is well tolerated (no GI side effects like metformin) and has been shown to improve insulin levels and reduce intense cravings.

A Combination of Myo and D-Chiro Work Best

Newer research into the effects of inositol have revealed that the majority of tissues in the body have a ratio of myo to DCI of 40:1. Taking a combination of these two supplements in this ratio rather than just taking myo or DCI alone, is recommended.

When compared to myo inositol, a combination of myo to DCI showed more benefits for improving metabolic parameters (lowering insulin, cholesterol, and inflammatory markers) in women with PCOS.

When compared with metformin, a combination of myo and DCI in a 40:1 ratio showed significantly better results in regards to weight loss, ovulation, and pregnancy rates (46.7 vs.11.2%).

Inositol Ratio Affects Egg Quality and Fertility

An imbalance in the body’s physiological ratio of myo to DCI ratio can affect egg quality. Myo inositol has been shown to improve egg quality in women with PCOS whereas DCI administered at high dosages (600-2400 mg daily) 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.

Inositol May Reduce The Risk For Gestational Diabetes

It has been suggested that women with PCOS may be at an increased risk for gestational diabetes (GDM) in pregnancy. Studies have shown that supplementing with myo inositol throughout pregnancy is effective at reducing the risk for GDM in women who were overweight and for women with PCOS. A study in Gynecology Endocrinology showed the prevalence of GDM among pregnant women with PCOS who took myo-inositol group was 17.4% versus 54% in the control group.

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Article Sources

  • Colazingari S, Treglia M, Najjar R, Bevilacqua A. The combined therapy myo-inositol 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.
  • Costantino D, Minozzi G, Minozzi E, Guaraldi C. Metabolic and hormonal effects of myo-inositol in women with polycystic ovary syndrome: a doubleblind trial. Europ review  med pharmacol sci. 2009;13(2):105-110.
  • 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.
  • D'Anna R1, Di Benedetto V, Rizzo P, Raffone E, Interdonato ML, Corrado F, Di Benedetto A. Myo-inositol may prevent gestational diabetes in PCOS women. Gynecol Endocrinol. 2012 Jun;28(6):440-2.
  • Dinicola S1, Chiu TT, Unfer V, Carlomagno G, Bizzarri M. The rationale of the myo-inositol and D-chiro-inositol combined treatment for polycystic ovary syndrome. J Clin Pharmacol. 2014 Oct;54(10):1079-92.
  • 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
  • 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.
  • Hamid A et al. Evidence-Based Women’s Health Journal. 2015;5(3):93–98.
  • Isabella R, Raffone E. Does ovary need D-chiro-inositol? J Ovarian Res. 2012 May 15;5(1):14.
  • 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.
  • Nordio M, Proietti E. The combined therapy with myo-inositol and D-chiro-inositol reduces the risk of metabolic disease in PCOS overweight patients compared to myo-inositol supplementation alone. Eur Rev Med Pharmacol Sci. 2012 May;16(5):575-81.
  • 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 Endrocrinology,23 (12): 700-703.
  • 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.
  • 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.
  • 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.