What is Gelatin? Gelatin is a protein and in aqueous solutions is a hydrophilic colloid. Gelatin derived from an acid-treated precursor is known as Type A, and it is derived from an alkali-treated precursor is known as Type B. What is Gelatin made of ? Gelatin is obtained by the partial hydrolysis of collagen derived from the skin, white connective tissue and bones of animals. The top four commercial sources of gelatin are Cowhide Splits, Bones (ossein) Pork Skin, and Fish Skin. Gelatin does not occur freely in nature, and cannot be recovered from horns, hoofs and other non-collagen containing parts of vertebrate animals. There are no plant sources of gelatin, and there is no chemical relationship between gelatin and other materials referred to as vegetable gelatin, such as seaweed extracts.