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 melÂ·aÂ·nin (mÄl'É-nÄ­n) n. Any of a group of naturally occurring dark pigments composed of granules of highly irregular polymers that usually contain nitrogen or sulfur atoms, especially the pigment found in skin, hair, fur, and feathers.