The best way to determine if your loc extensions are made with human hair, you can perform a burn test. Human hair burns slowly and gives off a strong smell similar to hair being burnt by a hot comb or flat iron. Human hair will burn into ash balls and crumble between your fingers. Synthetic hair will burn out quickly, and give off black smoke. Synthetic hair burns into a ball and hardens when cool. Synthetic hair has a off putting smell of burning plastic.