Measuring the levels of small molecules in the blood may be able to identify individuals at elevated risk of developing type 2 diabetes as much as a decade before symptoms of the disorder appear. Thomas Wang, from Massachusetts General Hospital (Massachusetts, USA) and colleagues have found that levels of five amino acids not only indicated increased diabetes risk in a general population but also could differentiate, among individuals with traditional risk factors such as obesity, those most likely to actually develop diabetes. Isoleucine, leucine, valine, tyrosine and phenylalanine were significantly associated with the later development of type 2 diabetes. Several of these amino acids were the same ones found in smaller studies to be elevated in individuals with obesity or insulin resistance, and other evidence has suggested they may directly affect glucose regulation.