Combination of Myo-inositol and D-chiro-inositol: A First-Line Treatment for PCOS
Inositol is a member of the B-vitamins and a component of the cell membrane. Inositol is found in fruits, beans, grains, and nuts and is also made by the body. While there are nine forms of inositol, myo (MYO) and d-chiro-inositol (DCI) types have been well studied in women with PCOS, both showing good results. Angela Grassi, MS, RDN, registered dietitian and founder of the PCOS Nutrition Center, used a MYO supplement for over a year and blogged about her positive experience with it. Our patients who take MYO have seen a reduction in cravings and menstrual cycle regularity.
MYO and DCI: Secondary Messengers
MYO and DCI are separate molecules that work differently in the body. It’s believed that women with PCOS may have a defect in “secondary messengers“ contributing to insulin resistance. MYO and DCI work as these secondary messengers. Simply put: when we eat foods (mostly carbohydrates), they get converted into glucose in our blood stream. We need the glucose to enter our cells to be used for energy. When blood glucose levels rise, a signal (imagine a doorbell is rung) is sent from the cell door to the nucleus telling it to open up. However, with PCOS, the doorbell on the cell door may be defective. This means that it takes longer for the cells to open its doors to glucose resulting in higher amounts of insulin needing to be secreted. Secondary messengers acts to repair the doorbell so that the cell doors open in response to glucose, resulting in less insulin needing to be secreted.
Inositol and Metabolic Effects
Both MYO and DCI have been shown to improve metabolic factors in PCOS, with MYO showing the most promise. One large randomized, double-blind, placebo-controlled trial showed that MYO (4 g/day) for 14 weeks, increased HDL (“good” cholesterol) levels and resulted in significant weight loss (and decreased leptin levels) in women with PCOS, although no change in insulin was detected.
In a double-blind placebo trial, Costantino et al showed that MYO (4 g/day) decreased insulin, triglycerides, testosterone, and blood pressure in women with PCOS.
Venturella et al showed that 2 g/day of MYO for six months resulted in significant weight loss and improved HDL and LDL levels.48 MYO at 1,200 mg/day for 12 weeks significantly decreased androgens and insulin in non-obese women with PCOS.
Inositol and Fertility Effects
Both MYO and DCI have been studied in infertile women with PCOS, with MYO showing the most promise in improving ovulation and egg quality. In a study published in 2007 in Gynecological Endocrinology, 25 women received MYO (4g/day) for six months. The results: 88% of patients had one spontaneous menstrual cycle during treatment, of whom 72% maintained normal ovulatory activity. A total of 10 pregnancies (40% of patients) were obtained.
Raffone et al compared the effects of metformin and MYO in women with PCOS. Sixty women received 1,500 mg/day of metformin, while 60 women received 4 g/day of MYO plus 400 mcg of folic acid. Ovulation was restored in 65% of women treated with MYO vs. 50% in the metformin group. More pregnancies occurred in the MYO group vs. metformin (18% vs. 11%).
A study published in the European Review Medical Pharmacology examined the effects of both forms of inositol in women with PCOS undergoing fertility treatments. One group received 2g of MYO twice daily and a second group with .6g of DCI twice daily. Women who received MYO had better, more mature eggs and more pregnancies than those who took DCI.
In a study authored by Nestler in 1999 in the New England Journal of Medicine, 1,200mg of DCI was given to women with PCOS for 6 to 8 weeks while another group received a placebo. Results: DCI increased the action of insulin, decreased androgens, triglycerides, blood pressure and improved ovulation (86% of women ovulated). However, when Nestler repeated this study in 2008, using double the amount of DCI (2400mg), the authors were unable to confirm their previous findings.
While DCI has been shown to improve insulin and androgens in PCOS, Isabella et al in 2012 showed that DCI alone, administered at high dosages (600-2400 mg daily) has been found to negatively affect oocyte quality and ovarian response. What’s more, the higher the dose of DCI, the worse the oocyte quality and ovarian response became.
This is because the ovaries don’t utilize insulin like other tissues. The ratio of MYO to DCI in follicular fluid is 100:1. Follicles with high quality oocytes have a higher concentration of MYO. DCI may be beneficial for improving insulin resistance elsewhere in the body, but high amounts of DCI can affect the body’s ideal balance of MYO to DCI and affect oocyte quality.
Inositol and Gestational Diabetes
It has been suggested that MYO can prevent GDM in women with PCOS. D’Anna et al. showed the prevalence of GDM in the MYO group was 17.4% compared with 54% in the control group.
Myo and d-Chiro Inositol Combined
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 an optimal ratio, the best results are seen.
Every tissue in the body has its own ratio of MYO to DCI (MYO is always much higher). DCI is produced from MYO when needed. New research has shown that a combination of MYO and DCI is a more effective approach for treating PCOS.
Women with PCOS who took a combination of MYO and DCI with a physiologic ratio of 40:1 (as seen in plasma), had better results than taking one supplement alone. These positive results include reduced risk of metabolic disease in PCOS overweight patients and improved IVF outcomes, making some authors to suggest that “the combined administration of MYO and DCI in a ratio of 40:1, should be considered as the first line approach in PCOS.”
How Much to Take?
It’s recommended that women with PCOS take a combined amount of MYO (2-4 grams) and DCI (50-100mg) in a physiologic ratio of 40:1. Currently, Ovasitol is the only supplement to combine MYO and DCI-and at the ideal ratio.
How to purchase Ovasitol
Generally, MYO and DCI are well tolerated but may cause low blood sugar, especially if taking medications or other supplements that lower blood sugar. MYO and DCI are safe to take during pregnancy. As always, check with your physician before starting inositol.
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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.
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