Vitamin B3 could have been made on icy dust grains in space, and later delivered to Earth by meteorites and comets, according to new laboratory experiments by a team of NASA-funded researchers. Vitamin B3, also known as niacin or nicotinic acid, is used to build NAD (nicotinamide adenine dinucleotide), which is essential to metabolism and probably ancient in origin. The result supports a theory that the origin of life may have been assisted by a supply of biologically important molecules produced in space and brought to Earth by comet and meteor impacts.