Peptides often feature in the ingredient lists of foods and cosmetics, but what actually are they? Aside from peptides of these kinds, our own bodies contain peptides produced when proteins synthesized from amino acids are broken down. This diverse array of peptides has a variety of hormonal effects demonstrating powerful physiological activity. As they are molecules that already exist within the human body, they are less toxic than chemically synthesized drugs and have therefore been attracting attention in the drug discovery field for some time.