The present invention provides a novel method for the preparation of a unique profile of primary aliphatic alcohols, having 24 to 30 carbon atoms, from the wax secreted by the insect Ericerus pela. Included in the present invention is the composition of matter, referred to herein as “polycosanol” produced by the method of this invention. The polycosanol composition is comprised primarily of the four primary aliphatic alcohols, tetracosanol, hexacosanol, octacosanol and triacontanol. Further included in this invention is the use of said composition of matter for the prevention and treatment of obesity, syndrome X, diabetes, hypercholesterolemia, atherosclerotic complications, ischemia and thrombosis.