myo-Inositol is an inositol isoform. Inositol is a derivative of cyclohexane with six hydroxyl groups, making it a polyol. It also is known as a sugar alcohol, having exactly the same molecular formula as glucose or other hexoses. Inositol exists in nine possible stereoisomers, of which cis-1,2,3,5-trans-4,6-cyclohexanehexol, or myo-inositol is the most widely occurring form in nature. The other known inositols include scyllo-inositol, muco-inositol, D-chiro-inositol, L-chiro-inositol, neo-inositol, allo-inositol, epi-inositol and cis-inositol. myo-Inositol is found naturally in many foods (particularly in cereals with high bran content) and can be used as a sweetner as it has half the sweetness of sucrose (table sugar). myo-Inositol was once considered a member of the vitamin B complex and given the name: vitamin B8. However, because it is produced by the human body from glucose, it is not an essential nutrient, and therefore cannot be called a vitamin. myo-Inositol is a precursor molecule for a number of secondary messengers including various inositol phosphates. In addition, inositol/myo-inositol is an important component of the lipids known as phosphatidylinositol (PI) phosphatidylinositol phosphate (PIP). myo-Inositol is synthesized from glucose, via glucose-6-phosphate (G-6-P) in two steps. First, G-6-P is isomerised by an inositol-3-phosphate synthase enzyme to myo-inositol 1-phosphate, which is then dephosphorylated by an inositol monophosphatase enzyme to give free myo-inositol. In humans, myo-inositol is primarily synthesized in the kidneys at a rate of a few grams per day. myo-Inositol can be used in the management of preterm babies who have or are at a risk of infant respiratory distress syndrome. It is also used as a treatment for polycystic ovary syndrome (PCOS). It works by increasing insulin sensitivity, which helps to improve ovarian function and reduce hyperandrogenism. Reduced levels of myo-inositol have been found in the spinal fluid of depressed patients and levels are significantly reduced in brain samples of suicide victims.