Non-suicidal self-injury (NSSI) refers to the deliberate, self-inflicted destruction of body tissue without suicidal intent and for purposes not socially or culturally sanctioned. This behavior is particularly prevalent among adolescents. NSSI is characterized by its urgency, compulsivity, and the sense of relief following the act, leading to its conceptualization as a behavior with addictive features. Through a systematic review of the literature, this article synthesizes current advances in the biology of adolescent NSSI from several perspectives: genetic and environmental factors, neurobiological development, pain perception, stress response and inflammation regulation, as well as the reward system and reward response. The overarching aim is to provide a scientific basis for the early identification of high-risk individuals, the prevention of adolescent NSSI, and the formulation of targeted intervention strategies and clinical research.