Obviously, there is no scientifically verifiable way to do it yet otherwise we would know.
But we are getting close. Cleansing senescent cells. DNA repair. Telomeres elongation. Health science is coming to consensus that the cause of aging is basically just damage over time, similar to scarring, but at the cellular level.
The most recent development is this:
https://www.independent.co.uk/life-style/gadgets-and-tech/anti-ageing-reverse-treatment-telomeres-b1748067.html 
