Some good news and bad news regarding the hormone testosterone: a new Australian study finds that testosterone treatment could significantly improve sexual desire, function and wellbeing in postmenopausal women.

International expert reaction this study has been positive.

On the downside, a US study finds that testosterone replacement therapy in ageing men – seeking to recover their drooping libido – have a 21 per cent high risk of suffering a heart attack or stroke.

Older men undergoing testosterone replacement therapy increase their risk of suffering a heart attack or stroke. Photo: Getty

Testosterone is generally regarded as a male hormone, and indeed is responsible for sperm production, the Adam’s apple, bigger muscles, deeper voice and hairier chests and ears.

Testosterone not only a male hormone

Testosterone is also an important hormone for women: it helps maintain sexual health, muscle strength, brain function and a healthy mood.

But testosterone gradually declines as women age – and can also drop sharply following surgical menopause – and with it goes the sex drive and function.

Monash University researchers reviewed 46 reports involving 8480 women, 95 per cent post-menopausal. The trials compared testosterone treatment to a placebo or to an alternative hormone treatment such as oestrogen, with or without progestogen.

Overwhelmingly, the studies found testosterone treatments can improve sexual desire, function and pleasure in postmenopausal women, which also improves their self-image and wellbeing.

Among the possible side effects found in some of these reports are an increase in acne, hair growth and some weight gain – but the number of participants who withdrew from clinical trials due to these side-effects “was not greater for women treated with testosterone compared with placebo, suggesting the effects are mild and not a major concern for participants”.

No serious adverse effects were recorded for glucose or insulin in the blood, for blood pressure, or for measures of breast health – although the latter needs further investigation.

Overall, testosterone therapies were found to be efficacious and safe – although further investigation was recommended – but there are no approved products or guidelines specifically for women.

“Our results suggest it is time to develop testosterone treatment tailored to postmenopausal women rather than treating them with higher concentrations formulated for men,” said senior author Professor Susan Davis in a prepared statement.

“Nearly a third of women experience low sexual desire at midlife, with associated distress, but no approved testosterone formulation or product exists for them in any country and there are no internationally agreed guidelines for testosterone use by women.

“Considering the benefits we found for women’s sex lives and personal wellbeing, new guidelines and new formulations are urgently needed.”

Off-label use of testosterone on the rise

Meanwhile, ageing men with low testosterone levels who take testosterone replacement therapy are – according to a new report in The American Journal of Medicine – at a slightly greater risk of experiencing an ischemic stroke, transient ischemic attack, or myocardial infarction, especially during the first two years of use.

The study analysed a large database of electronic medical records of patients enrolled in primary care practices in the United Kingdom and formed a cohort of 15,401 men, aged 45 years or older with low testosterone levels, a condition known as hypogonadism.

Testosterone replacement therapy (TRT) is only recommended for men with hypogonadism – and while reported rates have remained stable, over the past two decades in the US there has been a surge in prescriptions for TRT

It’s thought most of these men are trying to resurrect their diminished libido and masculinity.

Since 2000, a similar spike has occurred in Australia among men 45 and older, with one study concluding “the high rate of TRT initiation and low rate of recommended investigations suggest TRT may have been prescribed outside recommended indications”.

Link between testosterone and cardiac health unresolved

Previously some such studies have reported associations of testosterone treatment with higher risk of cardiovascular events. However, other such studies have reported contrary findings, associating testosterone treatment with lower risk of cardiovascular events and lower mortality. And for nought.

As the researchers observe: “There is limited evidence on the long-term clinical benefits of TRT to effectively treat the modestly declining levels of endogenous testosterone levels of ageing but healthy men.”

The 2018 (US) Endocrine Society clinical guidelines state that men with low testosterone, and who have had a recent heart stroke or heart, attack should not undergo supplementation, based on the concern that hormone therapy may not be safe for men with heart disease risk factors.

However, Dr Bu Beng Yeap, Chair, Medical Affairs Committee, Endocrine Society of Australia, told The New Daily there were limitations, with retrospective studies of testosterone prescriptions:

“Similar studies have reported associations of testosterone treatment with higher risk of cardiovascular events. However, other such studies have reported contrary findings.”

Dr Bu Yeap said the evidence gap “needs to be addressed by well-designed randomised controlled trials.”