It is a narcotic and may cause withdrawal symptoms if it is stopped too abruptly. Although Norco withdrawal can be quite unpleasant and uncomfortable, you can be assured that it is not life threatening. Norco withdrawal is possible in people who abuse Norco and in people who take Norco for a legitimate medical use.
Definition of melanin for English Language Learners. : a dark brown or black substance that is a natural part of people's skin, hair, and eyes.
Function of skin pigment. Melanin is a naturally produced polymer found in a multitude of locations in the body, from the eye and ear, to the brain and skin. Each different location contains a different variety of melanin, such as neuromelanin in the brain, and eumelanin and pheomelanin in the skin.