The general rejuvenation claim was the marketing-facing assertion of the Niehans practice and the basis for patient demand. It is grounded in patient self-report and clinic case description; it was never supported by a controlled outcome study during Niehans’s career. The claim is structurally identical to the rejuvenation assertions of Brown-Séquard (1889) and Voronoff (1920s) and anticipates the contemporary marketing of stem-cell tourism and biological-age-reduction services. None of these protocols has demonstrated rejuvenation on a hard mortality or disease-incidence endpoint in a controlled trial.