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 the brown pigment that produces the various shades and colors of human skin. Coloration (pigmentation) is determined by the amount of melanin in the skin. Without melanin, the skin would be pale white with shades of pink caused by blood flow through the skin.