An older person's leg is covered by a younger knee with money overlaid
  • Stem cell therapy, though costly and unregulated in the US, shows promise for age-related diseases.
  • The wealthy are flying to Aspen and the Bahamas for stem cell injections in their joints.
  • That includes tech CEO Bryan Johnson, who spends $2 million a year on his body and claims he now has "superhero joints."

It's hard to outrun aging if even a short walk makes your knees hurt.

Sure, you can tweak your diet, your workout, and even get Botox. But offsetting the wear-and-tear on our joints is not so simple.

Take tech entrepreneur Bryan Johnson, who — despite spending $2 million a year to feel 18 again — has struggled to find a fix for his achy, 46-year-old knees and hips.