Last spring, I began to realise that getting ahead of ageing had become the ultimate status symbol. I was sitting in the Harvard Medical School office of biologist David Sinclair, whose team had reversed signs of ageing in the tissues and muscles of elderly mice.

Dr Sinclair was talking excitedly about the various compounds he and other scientists were working on which trigger ancient protective circuits in the body. The night before, he told me with some glee, he had been across the river giving a talk to Harvard donors. While outwardly sceptical of his claims, many quietly asked him over drinks which pills - whether licensed as medicines or not - they should be taking.