Who wants to live forever? The human guinea pig and the Irish expert trying to stave off the ageing process

American tech millionaire Bryan Johnson puts his body on the line every day. There’s a rigorously strict exercise regimen, a calorie-controlled diet that means no food after 12.30pm, 40 different supplements and bed at 8.

30pm, without fail. He has also had his teenage son’s plasma injected into his body and has taken a controversial gene therapy treatment, plus a contentious drug that has not been approved by health authorities..