Mannose

Mannose, packaged as the nutritional supplement "d-mannose", is a sugar monomer of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylation are associated with mutations in enzymes involved in mannose metabolism.

Mannose is not an essential nutrient; it can be produced in the human body from glucose, or converted into glucose. Mannose provides 2-5 kcal/g. It is partially excreted in the urine.