Is eternal youth worth having? A middle-aged tech millionaire seeks the secret to never-ending adolescence for the affordable price of £1.6m per year. But is never growing old all it is cracked up to be?
The man spending millions to be 18 again
Price of youth: Johnson spends millions every year on experimental treatments to de-age his organs. Glossary
Mesopotamia - A historical region of the Middle East, mostly centred on modern-day Iraq, Kuwait and parts of Syria and Turkey. The name "Mesopotamia" in Greek means "between rivers" because of the Tigris and Euphrates that run through it.
Immortality - Staying alive forever.
Eternal - Lasting forever.
Elixir - A medicinal or magical potion.
Sigmund Freud - An Austrian psychoanalyst who was one of the world’s foremost authorities on psychology in the late 19th and early 20th Centuries. Although his ideas have been discredited in the scientific community, he remains influential for literary scholars.
Cryonics - The practice of freezing the bodies of people who have just died in the hope that future medical treatments will be able to save them.
Hubristic - Overly proud or self-confident.
Dementia - A syndrome associated with memory loss and other declining brain functions.
Dorian Gray - The character created by Oscar Wilde whose wish to stay young and beautiful is granted.