Agar Agar Powder is a natural gelling agent made from red seaweed, commonly used as avegan and vegetarian substitute for gelatin. Agar Agar Powder – 100% Natural Plant-Based Gelatin Substitute. Perfect forjellies, puddings, desserts, confectionery, sauces, and molecular gastronomy, agar agar is also popular in food science and modern recipes due to its stability at room temperature.