Maximilian Nierenstein (also known as Moses Max Nierenstein or Max Nierenstein; 1877–1946) was a professor of biochemistry at the University of Bristol. He is known for the Nierenstein reaction, an organic reaction describing the conversion of an acid chloride into an haloketone with diazomethane. In 1912, Polish biochemist Casimir Funk isolated a complex of micronutrients and proposed the complex be named "vitamine" (a portmanteau of "vital amine"), a name reportedly suggested by friend Max Nierenstein. He also worked on milk and caseinogen. He reviewed the discovery of lactose in 1936.