It is an object of the present invention to provide a marker substance capable of accurately determining a risk of developing metabolic syndrome in vivo. That is, the present invention provides the followings: a marker peptide for determining the risk of developing the metabolic syndrome; an antibody or an aptamer bound to the marker peptide for determining the risk of developing the metabolic syndrome; a microarray in which the antibody or the aptamer bound to the marker peptide for determining the risk of developing the metabolic syndrome has been immobilized on a carrier; a method for determining the risk of developing the metabolic syndrome, comprising measuring an amount or the presence or absence of the marker peptide for determining the risk of developing the metabolic syndrome in a biological sample collected from a subject; and a kit for determining the risk of developing the metabolic syndrome, comprising the antibody or the aptamer or comprising the microarray.