London - Like many of his generation, Rodney Hylton-Potts is defying conventional ideas about ageing.
At 69, he works full-time as a divorce lawyer, goes to the gym most mornings, plays golf once a week and has several foreign holidays a year.
But when he hit his 60s, there was one thing that started to dwindle. “About five years ago, I noticed my interest in sex was reducing,” says Rodney, who lives in West London with his partner and has five children from previous relationships.
“My partner is 16 years younger than me and very attractive, so I decided to do something about it.”
At the time, he was taking the PDE-5 inhibitor sildenafil, better known as Viagra, which improves erections by relaxing the smooth muscles of the penis and increasing blood flow.
But Rodney says what’s really made the difference is another treatment: injections of testosterone. Determined to improve his low libido, he went to a private Harley Street clinic that specialises in male health and, after blood tests and a discussion about his symptoms, was diagnosed with low testosterone.
“I was surprised when the doctor started asking about my mood,” says Rodney. But he says the jabs have given him a new lease of life. “My interest in sex is renewed,” he says. “Viagra’s reputation speaks for itself, but it’s irrelevant if what’s slipping is libido.
“A woman can forgive a man who is getting on a bit, but she might find it more difficult to excuse him losing interest in all her efforts. The other interesting thing about testosterone is it has an impact on your personality. There’s no question I’m less grumpy and less irritable. My partner thinks my doctor deserves a peerage.”
There is no doubt the arrival of PDE-5 inhibitors such as Viagra, Cialis and Levitra have had a major effect on the nation’s sex life. The number of prescriptions in England for sildenafil (including Viagra and other trade names it is sold under) and other PDE-5 inhibitors have soared from one million a decade ago to 1.7 million in 2014, according to statistics published last month by the Health and Social Care Information Centre.
But as Rodney’s experience suggests, Viagra might not always be the answer. Professor Geoffrey Hackett, a sexual health specialist at Good Hope Hospital in Birmingham, believes as much as half of the sildenafil prescribed to men will not work on its own because their real problem is low testosterone.
Testosterone is responsible for men’s energy, libido and sexual function, with many other important processes in the body. It is produced mainly in the testicles and levels are thought to start declining when a man is in his 40s.
Historically, testosterone injections or skin patches were only given to men with abnormally low levels due to a rare congenital condition, brain tumour or damage from chemotherapy.
But some doctors believe that many of the issues men experience in middle age - such as low libido, erectile dysfunction, fatigue and poor mood - are down to falling levels of testosterone, and these can be corrected with testosterone replacement therapy in the form of injections or pellets.
Professor Hackett suggests one in five men with erectile dysfunction has a testosterone deficiency.
“All men with erectile dysfunction should have their testosterone measured and treated if it’s low and associated with sexual dysfunction,” he says.
They may also need a PDE-5 inhibitor, such as Viagra.
“These are excellent drugs with benefits for the heart and blood vessels - and long may prescribing continue to increase. But diagnosing and treating the cause is as important as treating the erectile dysfunction.”
Dr Malcolm Carruthers, of the Centre for Men’s Health, believes that doctors should consider testosterone therapy when men report problems with sexualfunction.
“Viagra might work, at least for a while, but then the testosterone deficiency gets worse and the erectile dysfunction comes back,” he says.
Last week, Dr Carruthers published a study of data from 2 000 patients attending his clinics over the past 25 years, claiming 60 percent of patients found their symptoms improved with testosterone therapy, rising to 90 percent when a PDE-5 inhibitor was added (however, there was no control group, which is the gold standard for clinical trials).
Low testosterone is not the only potential underlying cause of erectile problems, says Professor Hackett. Impotence can also be an indicator of vascular disease, where arteries become narrowed as a result of poor diet, lack of exercise, smoking and genetics.
Patients and doctors should discuss this before beginning PDE-5 inhibitor treatment and, if necessary, a test such as an angiogram - where a special dye that shows up on an X-ray is injected into the arteries to reveal blockages - should be performed. Blocked arteries may require treatment with stents -tiny metal tubes that open it up.
Professor Hackett says low testosterone is not just a normal sign of ageing, and would like to see all over-50s screened for it, especially those with erectile dysfunction, diabetes and obesity. Under guidelines, low testosterone is defined as a reading below eight nanomoles per litre - the British Society for Sexual Medicine recommends if a man’s levels are low, tests should be repeated several times over six months before starting treatment.
However, men with impotence are rarely tested for low testosterone on the NHS.
Despite this, testosterone replacement therapy is gaining ground in Britain. NHS prescriptions for it increased by nearly 90 percent between 2000 and 2010, according to a study published in 2013 by a team at Newcastle University.
Over the same time, NHS spending on testosterone rose from £3.2-million to £11.7-million. However, it remains a controversial area.
In the US - where three percent of men over 40 reportedly take testosterone - concerns have been raised over side-effects, following studies suggesting there is a link with heart attacks and strokes.
It’s thought that testosterone may increase the number of red blood cells, raising the risk of clotting.
Researchers found some US doctors were prescribing testosterone inappropriately, diagnosing a deficiency on the basis of vague symptom questionnaires without proper testing. Testosterone levels fluctuate during the day and so should be measured in the morning and on more than one occasion to get an accurate picture.
In March, the US Food and Drug Administration said the benefits and safety of using testosterone in men with low levels due to ageing have not been established.
It said testosterone medicines should carry warnings about possible increased risk for heart attack and stroke.
Following a review last year, the European Medicines Agency said there is no consistent evidence of an increased risk with testosterone products.
However, it has called for them to carry warnings for those who might be at increased risk of heart disease or heart failure. The agency said: “Product information should make it clear testosterone should only be used when an abnormally low level of the hormone has been confirmed by signs and symptoms and appropriate laboratory tests.
“Testosterone levels naturally fall with age, but restoration of these levels in healthy older men is not an authorised use of the medicine in the EU.”
Some critics say that while many middle-aged men do have lower than ideal levels of testosterone, it tends to be a result of lifestyle such as being overweight or heavy drinking, and that it is not appropriate to treat them with replacement therapy.
“A man’s testosterone level naturally falls with age, but we don’t have evidence to show that replacing it with that of a younger man has any benefit,” says Professor Richard Ross, an endocrinologist at Sheffield University.
“And with no high-quality, large-scale, long-term studies, we have to be conscious of the potential for side-effects, such as the cardiovascular effects indicated in some studies.”
But proponents such as Dr Carruthers and Dr Hackett say the evidence saying there are problems with testosterone treatment is flawed.
Furthermore, untreated low testosterone is linked to poor health outcomes.
Earlier this year, a team from the University of Sheffield reported testosterone has an important role in how the body metabolises sugar and fat, and restoring depleted levels could potentially reduce deaths from type 2 diabetes and heart disease.
Professor Hackett says men suffering with sexual symptoms as a result of testosterone deficiency are losing their wives and families.
“Testosterone replacement therapy changes these people's lives,” he says.
Rodney Hylton-Potts says he has all the evidence he needs for continuing to use testosterone for the foreseeable future. He noticed a difference within days.
Five years on, he has a jab every two months at a cost of £200/R1 600 (his testosterone levels are checked every two to three months).
As the years have gone by he has noticed the effects of the jabs tailing off as he approaches his next appointment, so “tops up” with a testosterone skin gel. Rodney also takes the PDE-5 inhibitor Cialis.
He says his GP “pooh-poohed” the idea of testosterone replacement when he said he was having it. “He said it's a placebo effect and I shouldn't expect it to work. But it did work - he's wrong.”
“When my parents were my age, it was a question of walking in the Lake District, failing eyesight and no sex life. That's all gone now.
“If you can afford it, I would say it's a high priority to become a more cheerful person, to be more interested in sex and respond to your partner.”
Daily Mail