“In 2006, Shinya Yamanaka, a stem-cell biologist then at Kyoto University in Japan, and his colleague discovered that four proteins known as transcription factors — later dubbed Yamanaka factors — could transform an adult cell into an induced pluripotent stem (iPS) cell that is capable of taking on new identities.”

The new trial will test partial reprogramming: Instead of turning cells completely back into stem cells, it rolls back some ageing markers while preserving the cell’s function. The upside if this treatment is effective? Rolling back aging, and extending lifespan.

However there are still big risks and question marks. There’s a possible cancer risk from uncontrolled cell growth & questions as to just how much difference partial reprogramming can make to health.

This method to reverse cellular ageing is about to be tested in humans: A burgeoning field is launching its first clinical trial to find out whether dialling back cell development can safely refresh aged tissues and organs.