What has longevity research discovered about reversing aging?

The answer

In 2023, Harvard geneticist David Sinclair's lab demonstrated that gene therapy delivering three Yamanaka factors (OSK) restored vision in blind old mice by resetting epigenetic age without causing cancer. The concept of 'biological age' versus chronological age has been validated through epigenetic clocks developed by Steve Horvath, which measure DNA methylation at 353 CpG sites. A 2019 trial published in Nature showed that a cocktail of growth hormone, DHEA, and metformin reversed biological age by 2.5 years in nine participants while regenerating their thymus glands. Altos Labs, funded with $3 billion, and Calico (Google's longevity company) are now pursuing cellular reprogramming to extend human healthspan significantly.