Betaine is also called betaine anhydrous, or trimethylglycine (TMG) and is a substance that's made naturally in the body. In skin care, it can be a synthetic or naturally derived ingredient (typically from wheat bran/wheat germ) that increases hydration, protects the skin’s natural barrier, and enhances the texture of formulations. As a humectant it helps water to bind to the skin, balancing hydration levels.