Thanks. Much of what we call aging is oxidative processes. A gene that once encoded a protein properly no longer does, and the misfolded protein doesn't do as good as a job. That actually happens in your skin, and it plays a role in why old people have less elastic skin. However, we could in theory swap out the bad copies and replace them with new ones. Your skin would once again make the correct protein, and your skin would grow youthful looking again.

All of what we call aging comes down to physical changes. And these physical changes can, in theory, be reset. If your skin is new, and your bones and muscles strong, and your vascular system healthy, you've started to really turn back the clock.

Our cells break down after a number of divisions because it wasn't important for our evolution for them to go on forever. However, single-cell species don't die off because they get older with each new division. If you could imagine each cell in your body to be as viable as a single-celled organism, you'd have a body that didn't age very much.