process, as previously thought, but a loop triggered under certain conditions. Stress, nutrition, genes, and environment, all of these factors influence the activation of the cycle. But if those parameters are altered, the loop can be reset. In other words, the body can remember what it was like at 25 and begin to behave accordingly. This is not just life extension, this is biological rejuvenation. Then came the experiments, first on cells, then on tissues,