Agar is a gelatinous substance derived from SEAWEED. It is used in many culinary and scientific applications, such as a thickening agent for soups and sauces, a medium for growing bacteria in laboratories, and a vegan alternative to gelatin. Agar is also known as agar-agar, kanten, or Japanese isinglass. It is made from the cell walls of red algae and is composed of two components: agarose and agaropectin.