What is the role of inositols in infertility treatment for PCOS?

[Terminology: PCOS was renamed polyendocrine metabolic ovarian syndrome (PMOS) by global consensus in May 2026, published in The Lancet. The International Guideline now uses PMOS/PCOS in its recommendations and will use PMOS alone from 2028. Clinical content, diagnostic criteria and management are unchanged.]

For PCOS patients undergoing IVF specifically, ESHRE (2026) recommends against inositol: Myo-inositol before or during ovarian stimulation is probably not recommended for women with PCOS undergoing IVF (conditional). Myo-inositol is not recommended in low responders (strong). Myo-inositol is not recommended in non-PCOS women undergoing IVF (strong). An important scope distinction. These recommendations concern inositol as an adjunct to ovarian stimulation in IVF. They do not directly address inositol used for cycle regularity or metabolic endpoints in PCOS outside of IVF, which is a separate question the ovarian stimulation guideline does not cover. That said, the direction of travel is worth noting when counselling. The evidence base has not strengthened, and a guideline group reviewing it in 2025 moved to recommending against in the IVF context rather than remaining neutral. Practically: inositol is inexpensive, widely used and generally well tolerated, so patients frequently arrive already taking it. There is no strong reason to insist on stopping it for metabolic indications, but it should not be presented as improving IVF outcomes, and it should not displace measures with better evidence.