D-chiro-inositol

D-chiro-inositol as monotherapy in PCOS has no quality evidence base. Most inositol PCOS RCTs used either myo-inositol monotherapy or myo:D-chiro 40:1 combination (Inofolic Combi, Ovasitol). Pundir 2018 (BJOG) meta-analysis found no benefit of 40:1 combination over myo-inositol monotherapy in PCOS. ESHRE 2023 PCOS guideline classifies inositols (without specifying form) as experimental therapy with possible effect. SEGO 2017 lists hormonal contraceptives or metformin first-line for PCOS anovulation. If D-chiro-inositol monotherapy was recommended for PCOS, myo-inositol monotherapy or 40:1 combination under gynaecology supervision is preferable.

D-chiro-inositol is an inositol isomer sold as a supplement and promoted for blood sugar control and better insulin sensitivity. For type 2 diabetes the convincing benefit has not been shown: there is no evidence base for this use, and the available data are weak and do not confirm an effect on glucose or HbA1c. What helps type 2 diabetes is changes to diet and weight, regular physical activity, and medicines with an established evidence base such as metformin. The compound itself is harmless in this role, but it should not replace prescribed treatment.