What is Glucosamine? Glucosamine is a naturally occurring sugar-related nutrient, which is important in normal joint function. Glucosamine is produced within the body; however as people age the capacity to manufacture sufficient levels of glucosamine is reduced. Glucosamine is not present in significant amounts in most diets. Vegetarian supplemental sources are derived from fermented corn. What Does Glucosamine Do? Glucosamine sulphate may help to support healthy joints.