UPDATE: a fresh look at the same topic from 6:2.18 courtesy of The Times

Testosterone deficiency, or low-T as it is popularly known in America, has long polarised medical opinion. Testosterone evangelists promote it as the panacea to middle-aged woes like poor sex drive, grumpiness and lack of energy, while at the other extreme sceptics regard supplementation as the unacceptable medicalisation of natural ageing.   But who is right?

Neither of them in my opinion, which is why I welcome new guidance from the British Society for Sexual Medicine which treads a path between these two extremes, confirming that testosterone deficiency is both real and common, but that not every man with low levels needs hormones to boost them.  

Testosterone deficiency can occur at any age and for a number of different reasons, but the bulk of the new guidance is aimed at the age-related decline seen in men over-40.  It is estimated that around 1in 10 men of this age has a low or borderline testosterone level, but that only 1 in 50 needs testosterone supplements. So how do you decide who does and who doesn’t?

Sexual problems , such as reduced libido and difficulties getting an erection, are the most common symptoms of low-T, but others include fatigue, poor sleep and depression.  All can be caused by myriad other problems common in middle age – not least stress – but where sexual dysfunction is prominent, a blood test to measure testosterone levels should always be part of the routine investigation. And because testosterone levels vary throughout the day (they are highest in the morning) it is important to take blood at the right time (before 11am according to the new guidelines).

If the result comes back as 12 nmol/l or higher then testosterone deficiency is unlikely to be the cause of  the man’s complaints. And if the reading is lower than 8 (and it should be repeated at least once to confirm this) then testosterone replacement therapy (TRT) is likely to be required. As ever in medicine it is the grey area in between – a reading between 8 and 12 – that confuses both doctor and patient.  

Men with higher readings (12 or more) generally only need reassurance. Those with levels under 8  should be referred to a specialist to decide if TRT is appropriate and what type (typically gel or patch) and dose.  While those men in-between (8-12) need further blood tests to check how much of their circulating testosterone is actually available (so-called free testosterone) before dismissing supplementation as some of them will still benefit.  

In many men with  borderline readings their lowish levels of testosterone are simply  a marker of their general health. If you are overweight, have type 2 diabetes, drink too much alcohol, or regularly take opiate based painkillers (such as codeine) then your testosterone level is likely to be on the low side.  Equally if you are slim, active and healthy it is likely to be normal whatever your age. So if free testosterone levels are OK in borderline cases I encourage weight loss and lifestyle change where applicable and re-test after 12 months.   

Compared with HRT in women, TRT is still in its infancy and there is fierce debate about the pros and cons.  Studies suggest that in the short term men can expect a boost to their sex drive, more energy, stronger bones and improved physical and mental stamina. But at what cost?  Potential worrying side effects range from acne and aggression to reduced fertility, and an increased risk of prostate cancer and heart disease. However the evidence is conflicting with some research suggesting that TRT protects against heart disease.

It may be a decade or more before we know for sure about the long term risks. In the meantime I would not even consider TRT unless I had a proven deficiency.  You can access the latest guidelines on diagnosis and treatment at http://www.bssm.org.uk/wp-content/uploads/2017/12/guidelines-on-adult-testosterone-deficiency-with-statements-for-uk-practice.pdf


Symptoms associated with low testosterone levels include:



  • Loss of sex drive, difficulty achieving or maintaining an erection (including loss of early morning erection) and reduced orgasmic sensation
  • Fatigue,poor sleep, hot flushes, night sweats, reduced physical strength and stamina and low mood
  • Weight gain, particularly around the midriff (although, this can cause low testosterone as well as result from it)
  • Decreased body hair and breast enlargement.


Edited to add: I have had lots of emails asking for specific advice on individual cases / interpret readings etc (see below) but really can’t give definitive answers on a blog. Medicine by email has its limitations, so please direct any clinical queries to your own GP / specialist. Thank you.