The endocrine system is made up of a number of glands that produce and secrete hormones into the bloodstream. These hormones regulate various physiological functions including metabolism, growth, sexual function and development. Anything that can alter the function of the endocrine system may consequently have an impact on an individual’s health. The effect of soyfoods on the endocrine system has received a great deal of interest mainly because soybeans are a source of isoflavones. Isoflavones belong to a group of compounds called phytoestrogens which show structural similarities to the female hormone estrogen and therefore may exert weak estrogenic-like effects. This property raised concerns that isoflavones may affect the endocrine system. To better understand this topic it’s important to have an accurate understanding of isoflavones.