You’ve probably heard of the great program Locks of Love, in which people donate long hair to make wigs for sick children, but did you know that short hair clippings are used as cheap fertilizer and as food additives? Mother Jones explains:
Human hair isn’t the only source of L-cys. You can extract it from poultry feathers or even synthesize it in a lab–although the end product is no different than what you’ll get by dumping tons of barbershop waste into vats of hydrochloric acid and separating the coveted compound from the resulting chemical stew. George Cherian, chairman of Indian hair exporter Raj Impex Hair, however, has long been the cheapest source of L-cys. You’d be hard pressed to find a richer source: Human hair contains up to 20 percent cysteine by weight, while duck feathers may yield only about half as much.
But you’d be equally hard pressed to find food manufacturers willing to admit that they use the hair-derived version.