Abstract Background The safety of gluteal fat grafting is a global concern in plastic surgery. Objective The goal of this study was to test whether fat grafting to the buttocks with Auto Stop Reach (ASR) technology prevents penetration from the subcutaneous space into the fascia and muscle layers of the buttocks. Methods Fat transfer simulation was performed with blue dye on 8 fresh tissue cadaver buttocks by 3 board-certified plastic surgeons (S.S.K., S.C., B.W.). An open control was utilized to visualize the process in the different anatomic layers, and all of the other procedures were performed blindly, akin to live surgery. After blue dye transfer reached maximum capacity (ranging from 400-800 mL per buttock), dissection of the anatomical layers of the buttocks was performed to determine the plane(s) of injection. Results Blue dye fat transfer injection to the buttocks did not penetrate the gluteal fascia or muscle layers from the subcutaneous space while using ASR. Conclusions Auto Stop Reach technology supports the safety of gluteal fat transfer in the subcutaneous space by board-certified plastic surgeons. Level of Evidence: 4