(1) Background: Myoinositol (MI) and D-chiro-inositol (DCI) are involved in a number of biochemical pathways within oocytes having a role in oocyte maturation, fertilization, implantation, and post-implantation development. Both inositols have a role in insulin signaling and hormonal synthesis in the ovaries. (2) Methods: Literature search (with key words: inositols, myo-inositol, d-chiro-inositol, PCOS) was done in PubMed until Sept. 2020 and 197 articles were identified, of which 47 were of clinical trials (35 randomized controlled trials). (3) Results: Many studies have demonstrated that in patients with polycystic ovarian syndrome (PCOS) MI treatment improved ovarian function and fertility, decreased the severity of hyperandrogenism including acne and hirsutism, positively affected metabolic aspects, and modulated various hormonal parameters deeply involved in the reproductive axis function and ovulation. Thus treating with MI has become a novel method to ameliorate PCOS symptoms, improve spontaneous ovulation, or induce ovulation. The current review is focused on the effects of MI and DCI alone or in combination with other agents on the pathological features of PCOS with focus on insulin resistance and adverse metabolic outcomes. (4) Conclusions: The available clinical data suggest that MI, DCI, and their combination in physiological ratio 40:1 with or without other compound could be beneficial for improving metabolic, hormonal, and reproductive aspects of PCOS.

中文翻译：

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多囊卵巢综合症中的肌醇

(1)背景：肌醇(MI)和D-手性肌醇(DCI)参与卵母细胞内的许多生化途径，在卵母细胞成熟、受精、植入和植入后发育中发挥作用。两种肌醇在卵巢中的胰岛素信号传导和激素合成中发挥作用。（2）方法：截至2020年9月在PubMed上进行文献检索（关键词：肌醇、肌醇、d-手性肌醇、PCOS），共找到197篇文章，其中47篇为临床试验（35篇随机对照试验）。(3) 结果：许多研究表明，多囊卵巢综合征 (PCOS) 患者的 MI 治疗可改善卵巢功能和生育能力，降低雄激素过多症（包括痤疮和多毛症）的严重程度，积极影响代谢方面，并调节与内分泌密切相关的各种激素参数。生殖轴功能和排卵。因此，MI治疗已成为改善PCOS症状、改善自发排卵或诱导排卵的新方法。目前的综述重点关注 MI 和 DCI 单独使用或与其他药物联合使用对 PCOS 病理特征的影响，重点关注胰岛素抵抗和不良代谢结果。(4)结论：现有的临床数据表明，MI、DCI及其以生理比例40:1联合或不联合其他化合物可能有益于改善PCOS的代谢、激素和生殖方面。