L-(-)-Glucose is not commonly found in nature and is not metabolized by most biological systems, which primarily utilize D-(+)-glucose. Due to this unique property, L-(-)-glucose is used in scientific research as a non-metabolizable analog of glucose. It serves as a control in studies involving glucose transport and uptake in cells, helping researchers distinguish between active metabolic processes and passive diffusion. It has been investigated for potential use in medical diagnostics, particularly in renal function tests, because it can be filtered by the kidneys but not reabsorbed, allowing measurement of glomerular filtration rate without interference from metabolism. Additionally, L-(-)-glucose is explored in the development of specialty sugars and low-calorie food additives, as it is not broken down for energy in the human body. Its structural similarity to D-glucose allows it to mimic sugar in taste and physical properties without contributing to caloric intake or blood glucose levels. However, its use in food remains limited due to cost and lack of large-scale safety data.