The safety claim was central to the procedure’s commercial viability. The claim rests on the absence of catastrophic immediate complications in Voronoff’s documented case series; it does not address graft rejection (which was poorly understood at the time and was not measured), cross-species pathogen transmission (which was unrecognised in the 1920s and which would later be considered a primary concern for primate xenotransplantation in modern policy), or longer-term consequences. The claim is refuted by current xenotransplantation policy, which heavily restricts primate-to-human tissue transfer specifically on the grounds the Voronoff protocol explicitly dismissed.