Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trials

Abstract

Myo-inositol (MI) supplementation in women with polycystic ovary syndrome (PCOS) has been evaluated over the last years. Many hormonal and reproductive impairments associated with this disorder seem relieved by the supplement. The objective of the meta-analysis was to assess the effects of MI alone or combined with d-chiro-inositol (DCI) on the endocrine and metabolic abnormalities of women with PCOS. Literature was retrieved from selected databases, MEDLINE, EMBASE, PubMed and Research Gate (up to November 2016). Only randomized controlled trials (RCTs) investigating the effects of MI alone or combined with DCI were reviewed. Nine RCTs involving 247 cases and 249 controls were included. Significant decreases in fasting insulin (SMD = −1.021 µU/mL, 95% CI: −1.791 to −0.251, P = 0.009) and homeostasis model assessment (HOMA) index (SMD = −0.585, 95% CI: −1.145 to −0.025, P = 0.041) were identified after MI supplementation. The trial sequential analysis of insulin meta-analysis illustrates that the cumulative z-curve crossed the monitoring boundary, providing firm evidence of the intervention effect. A slight trend toward a reduction of testosterone concentration by MI with respect to controls was found (SMD = −0.49, 95% CI: −1.072 to 0.092, P = 0.099), whereas androstenedione levels remained unaffected. Throughout a subgroup’s meta-analysis, a significant increase in serum SHBG was observed only in those studies where MI was administered for at least 24 weeks (SMD = 0.425 nmol/L, 95% CI: 0.050–0.801, P = 0.026). These results highlight the beneficial effect of MI in improving the metabolic profile of women with PCOS, concomitantly reducing their hyperandrogenism.

Ovulation induction strategies in polycystic ovary syndrome

“…4,5 Furthermore, and like that seen with metformin administration, endocrine and metabolic parameters in PCOS also seem to be altered in favorable ways by myoinositol, the most abundant inositol isomer. 6 We fully agree with Levin and Rottenstreich that the documentation on inositol isomers for ovulation induction in PCOS is scarce and that large randomized controlled trials are greatly needed. Such studies seem to be under way.…”

Altered Ovarian Inositol Ratios May Account for Pathological Steroidogenesis in PCOS

“…Another recent meta-analysis [ 48 ] examined 9 randomized controlled trials (RCTs) on PCOS women (247 cases and 249 controls) [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. The authors evaluated the efficacy of supplementing MI alone, or in association with DCI in the 40:1 ratio, considering fasting insulin concentrations as the primary outcome, while HOMA index and serum levels of testosterone, androstenedione and sex hormone-binding globulin (SHBG) as secondary.…”

Comparison of the effect of two combinations of myo-inositol and D-chiro-inositol in women with polycystic ovary syndrome undergoing ICSI: a randomized controlled trial

“…Inositol has two major stereoisomers: myo-inositol (MYO) and Dchiro-inositol (DCI). MYO supplements have been observed to improve the metabolic profile and hyperandrogenism of women with PCOS [4,5], in addition to increasing the clinical pregnancy rate in infertile women undergoing ovulation induction for ICSI or IVF-ET, probably improving the quality of embryos and reducing the number of unsuitable oocytes [6]. However, a recent systematic review showed that MYO supplementation is not sufficient to improve oocyte maturation, embryo quality or the pregnancy rate [7].…”