The present mechanism of metabolic formation of cholesterol is discussed and difficulties arising with the mechanism highlighted. A revision of the chemical reactions in biological cells which give rise to cholesterol and other sterols is presented. This mechanism of cholesterol formation is based on the forms and properties of polyphosphoric acids which are compounds common to both plant and animal cells. The reactions are examples of biochemical reactions which involve the stereochemistry of an inorganic molecule as well as the stereochemistry of organic molecules. It is demonstrated that cholesterol and related compounds entering or produced in the human metabolism are decomposed by the fluids of the digestive system and one product recycled for the production of further cholesterol. Links between the formation of cholesterol and degenerate conditions, such as obesity and diabetes, encountered in the human metabolism are discussed. Obesity and Metabolism 2011; 7: e6-e16.