This randomized controlled trial will evaluate the efficacy of a Transtheoretical Model (TTM)-based behavior-change intervention, delivered through stage-matched counseling sessions, on anabolic-androgenic steroid (AAS) use among gym-goers, compared with a control group receiving standard health education. Non-medical AAS use is a growing public health concern in gym and fitness settings and is associated with serious cardiovascular, endocrine, hepatic, and psychiatric harms. Participants will be randomly assigned to either a TTM-based intervention group or a control group. The intervention will tailor counseling content to each participant's stage of change (precontemplation, contemplation, preparation, action, or maintenance) regarding AAS use. The findings of this study will provide evidence on the effectiveness of stage-based behavioral counseling in reducing AAS use and progressing gym-goers toward safer, drug-free training practices.