Background: Insulin resistance is a hallmark of Polycystic Ovary Syndrome (PCOS). Insulin sensitisers, most notably metformin, are thus used to treat the condition, but may be accompanied by gastrointestinal side-effects. The novel isomeric insulin sensitising agents D-chiro-inositol (DCI) and Myo-inositol (MI) improve insulin resistance by acting at the peripheral and ovarian level, respectively, whilst largely being devoid of adverse effects.
Objectives: To assess the efficacy of DCI and MI, alone or combined, on restoration of ovulation and reduction of hyperandrogenism in women with PCOS.
Methods: The following databases were systematically searched: CENTRAL, Ovid-EMBASE, Ovid-Medline, Global health library, SCOPUS and PUBMED. Joint primary outcomes were defined as effect on ovulation and improvement of dermatological manifestations of hyperandrogenism, with effect on serum androgen levels categorised as a secondary outcome.
Results: Eleven trials were deemed suitable for systematic review. Six analysed the effect on ovulation using serum progesterone, luteal ratio or percentage of participants who ovulated. Compared to placebo, MI and DCI led to a rise in mean peak progesterone and an improvement in luteal ratio. Two studies reported a reduction in acne, and hirsutism decreased in all trials with MI treatment. Neither isomer was found to be superior to the other in improving the manifestations of hyperandrogenism. A value of −0.76 for cohens d measure of effect size (CI −0.17 to −1.35) after 6 months of combined treatment favoured dual isomeric treatment over monoisomeric (MI) treatment for reduction of serum androgen levels.
Conclusion: Myoinositol and D-chiro-inositol both appear to be effective in improving ovulation and reducing hyperandrogenism in women with PCOS. Further randomised controlled trials are needed to establish whether dual isomer therapy offers additional benefits compared to either agent alone.