Spinal manipulation probably does not “make you immortal” … or even accomplish any lesser miracles. It probably just (at best) creates “a non-specific neurophysiological effect that may transiently improve pain, range of motion, and function about the spine.” From this nicely presented and cheeky evaluation of spinal manipulation by Nick Hannah, PT:
Only the immortality item is satirical. Do chiropractors actually claim that spinal manipulation can do things like cure allergies or prevent the need for vaccines? Oh, indeedy! And that’s just the tip of the iceberg.