E635 may or may not be vegan. It is a food additive used to enhance flavor. Also known as Disodium 5′-Ribonucleotides, E635 is made of Sodium Salts of Inosinic Acid and Guanylic Acid. These sodium salts are often obtained from the flesh of killed animals but can also come from plants. Please check with the manufacturer. When you see an “E-number” like E635, it refers to an ingredient that has been approved by the European Union for use as a food additive.