What is Glycerol? Glycerol is a naturally occurring chemical. People use it as a medicine. Some uses and dosage forms have been approved by the U.S. Food and Drug Administration (FDA). Glycerol is taken by mouth for weight loss, improving exerciseperformance, helping the body replace water lost during diarrhea and vomiting, and reducing pressure inside the eye in people with glaucoma. Athletes also use glycerol to keep from …