Testolone (RAD-140) is a selective androgen receptor modulator investigated for its potential influence on lean muscle development, strength, and physical performance. Research interest centers on its selective interaction with androgen receptors, particularly within muscle and bone tissues, and its potential anabolic activity. RAD-140 continues to be examined in studies related to body composition, muscle preservation, tissue response, and performance-associated pathways. Its selective characteristics have contributed to ongoing scientific investigation within advanced musculoskeletal and androgen receptor research fields.