Where does Human Hair come from?
You will be surprised that the human hair for wigs can come from Russia, Germany and most commonly China, Korea & India. The hairs from China, Korea & India are of course black and brown in colour, so this hair has to be bleached and then dyed to the various other colours that are available.
All human hair that is cut from their owners heads has to go through an aggressive treatment process with acid and other chemicals. These chemicals destroy the cuticle partly or totally.
Some human hairs that are cheaper are sometimes mixed with animal and synthetic hair, for this helps to lower the price. In the hair industry, this hair is commonly called processed hair.
To buy really good quality human hair you would be looking to buy hair that is called virgin hair. It’s called virgin hair because it still has its cuticle in tact and that these are all facing the same way Virgin hair also should have not been permed, dyed, colored, bleached or chemically processed in any way. To get this level of high grade hair there are people who are called “hair collectors”, whose job is mainly to cut the hair directly from people’s heads and then that hair is bundled into ponytails.

DailyMail.co.uk

Whose Hair Is it anyway (dailymail.co.uk)