Currently, hairdressers around the world throw away tonnes of human hairs after they have given someone a new hairstyle. I know people sometimes donate their hair, which can be used to create wigs.
I wonder whether there are other new or unexpected ways hairs could be recycled or upcycled to create new products. Perhaps it can be dissolved and useful substances or molecules can be gathered. If so, could you point me towards some (research) articles or books that show how the hairs are used, and how they are processed?