"Black Gold." That's what the $900 million hair market is called, according to Scott Carney in his book The Red Market.
It seems our hair is a hot commodity, the obvious end market being hair extensions and wigs. There is another end market, too, not nearly as obvious.
As leavening. Check out this npr interview, where Melissa Block talks with Carney. In India, the Sri Tirumala Temple (which accounts for about 40-percent of the international hair market) does a brisk business selling long hair for extensions, but also shorter, mostly men's hair. Where does the mixed hair go? To chemical companies, where it "gets reduced to an amino acid called L-cystine, which is used as a leavening agent in baking goods," Scott Carney explains.
We are eating our own hair. Eew.
This time, I should add, it's not only about hair. Scott Carney's book explores the global market for blood, bones and organs, aka the "red market." Whoa. Gruesome doesn't begin to cover it.