N-Fmoc-L-alanine-d4 is the isotope labelled analog of N-Fmoc-L-alanine (F619945); the Fmoc-protected form of L-Alanine (A481500). L-Alanine is used to make in-vivo measurement of glucose and alanine metabolism in studies of patients with diabetes. L-Alanine is a non-essential amino acid for human development and is one of the 20 amino acids encoded by the genetic code.