The biotech guru Bryan Johnson is dedicated to exploring (and exploiting) the possibilities of reversing the biological ageing process, and his main subject is himself. The 46-year old works with a team of 30 personal doctors to monitor every detail of his body, with the aim of achieving the biological age of an 18 year old.

His medical team collects data and also administers a range of procedures and treatments that would put any elite athlete or performer in the shade. He claims to have the fitness and lung capacity of an 18-year old, the skin of a 28-year old, and the heart of a 37-year old. In the last three years, he has spent over $4m in the pursuit of eternal youth.

This manic health fixation includes some extreme and painful procedures, including a course of experimental shockwave therapy on his penis. In a recent interview with The Guardian, Johnson explained that a wand device is used to send targeted sound waves along the tissues of his penis, describing the pain levels as ‘nine out of ten’.

The idea is that by causing micro-injuries to the tissue of the penis, it stimulates younger and stronger cells to regenerate, improving sexual function. Johnson claims that he now has the penile health of a man 15 years younger, which is presumably good news for his sex life.

However, experts warn that shockwave therapy should not be seen as the holy grail for men who are experiencing sexual dysfunction. This is because difficulty getting or keeping an erection is often the first sign of a more serious underlying health problem such as heart disease, high blood pressure, or diabetes.   

 Dr Amin Herati, director of male infertility and men’s health at Johns Hopkins hospital, told the publication: “The barometer of men’s health is erectile function: how strong the erection is, and the ability to maintain erection.”

Petar Bajic, director of the Center for Men’s Health in the Glickman Urological and Kidney Institute at the Cleveland Clinic adds that the ‘divining rod of vascular health’, and explains: “There’s some solid evidence that ED can precede a heart attack by five years.”

This is because the arteries that supply blood to the penis are less than a millimetre in diameter, so any narrowing of the arteries caused by fat build up is apparent in the early stages of cardiovascular problems. 

The doctors emphasise the importance of taking cardiovascular exercise to maintain good penile health, with the aim to carry out an activity that gets you out of breath three to four times a week. Other lifestyle changes such as eating healthily, getting enough sleep and cutting back on drinking and smoking can also make a big difference.

For men who still experience problems, there is a new ED treatment available called Eroxon Stimgel, which can be applied externally to the penis and takes effect within 10 minutes.