In simple terms: a vitamin-like compound (myo and D-chiro) involved in insulin signalling inside cells.
Why it matters for PCOS
Inositol is a group of vitamin-like compounds that help cells respond to insulin. Two forms, myo-inositol and D-chiro-inositol, are commonly discussed for PCOS because insulin resistance is often part of the picture. Studies link inositol to cycle regularity and metabolic markers, but the evidence is moderate, so it is not a guaranteed treatment for every woman.
Inositol is sold as a supplement, not a prescription medicine. Even so, it is worth checking with a doctor or pharmacist first, especially if you are pregnant, trying to conceive, or taking other medicines.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.