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.
Melanin is a pigment that is produced by cells known as melanocytes in the skin of most animals. It comes in two basic forms: eumelanin (brownish color) and pheomelanin (reddish-brown color). The production of melanin is affected by UV exposure, genetic make-up, size of melanocytes, and disease conditions.elanin is a pigment produced in the skin of almost all animals on earth. Its role in animal survival is critical, and varies depending on the organism. This article addresses melanin function and expression in humans and other organisms, and its role in survival.