Cyclitols play a particularly important role in cell functioning because they are involved in ion channel physiology, phosphate storage, signal transduction, cell wall formation, membrane biogenesis, osmoregulation and they have antioxidant activity. They are involved in the cell membranes as a phosphatidyl myo-inositol, an inositol triphosphate precursor, which acts as a transmitter that regulates the activity of several hormones, such as follicle-stimulating hormone, thyrotropin, and insulin. The aim of this paper is to characterize the selected cyclitols: myo-inositol, D- chiro-inositol, and D-pinitol in type-2 metabolic syndrome and diabetes treatment. Results and discussion: Cyclitols have certain clinical applications in the treatment of metabolic syndromes and are considered to be an option as a dietary supplement for the treatment or prevention of gestational diabetes mellitus and type-2 diabetes. Improved metabolic parameters observed after using cyclitols, like myo-inositol, in the treatment of polycystic ovary syndrome and type-2 diabetes suggest that they may have a protective effect on the cardiovascular system. Pinitol, together with myo-inositol,maybe responsible for improving lipid profiles by reducing serum triglyceride and total cholesterol. Pinitol is also well-researched and documented for insulin-like effects. Myo-inositol, D -chiro-inositol, and D-pinitol indicate a number of therapeutic and health-promoting properties.