Testosterone Replacement Therapy or “T” is a medical treatment for symptoms typically associated with low testosterone levels or male hypogonadism. These are things like low sex drive, erectile dysfunction, and loss of a male pattern of facial and body hair as well as muscle mass and fat distribution. Testosterone replacement may also improve mood and energy levels and strengthen bones such that they are less likely to fracture.
Like all medical treatments, men who decide to use testosterone should discuss the potential benefits and risks with their doctor and make a decision that best suits them as an individual. Like most medical treatments the benefits of testosterone are greatest when they are combined with healthy lifestyle strategies such as exercise and quitting smoking.
Who should consider testosterone therapy?
There is unlikely to be any benefit from taking testosterone in men who have normal testosterone levels and so treatment is best aimed at men with consistently low testosterone. As testosterone levels fluctuate through the day the best way to identify these men is through a blood test done early in the morning and repeated on a separate occasion to make sure there is a true deficiency in testosterone.
The lower the testosterone level is prior to treatment the greater the benefit is likely to be so men with very low testosterone levels are good candidates for treatment.
Some symptoms are more closely related to having a low testosterone than others and men with those symptoms are most likely to benefit. The symptoms most closely associated with low testosterone are:
- low sex drive
- erectile dysfunction
- reduced bone density
- loss of body fair
- small testes
- hot flushes and sweating
Men with symptoms that could be related to low testosterone but could also be related to many other things are less likely to benefit. The symptoms that are less strongly associated with low testosterone are:
- being overweight
- reduced muscle strength and bulk
- reduced energy levels
- feeling depressed
- poor concentration and memory
Who should not use testosterone therapy?
The harms of using testosterone are likely to outweigh the risks in each of the following groups.
- Men who do not have consistently low testosterone levels are unlikely to benefit from testosterone therapy but have the same risk of harm from testosterone therapy.
- Men who want to have a baby. Testosterone therapy suppresses natural sperm production and will usually make men infertile.
- Men with untreated obstructive sleep apnoea are at risk of their sleep apnoea worsening with testosterone treatment putting them at risk of daytime sleepiness, high blood pressure, diabetes, heart disease and stroke
- Men with symptoms of an enlarged prostate like needing to wake up multiple times at night to pass urine might find these symptoms get worse with testosterone therapy and are even at risk of bladder obstruction requiring treatment in hospital
- Men with breast cancer or prostate cancer should avoid testosterone therapy as this might make these forms of cancer more aggressive. After these cancers have been successfully treated it may be safe to use testosterone but cases are considered individually.
- Men with heart failure may have worsening fluid retention if they take testosterone therapy.
How well does testosterone replacement work?
Testosterone therapy can be very effective in some men but there are also times when it doesn’t work very well. In general the lower the testosterone level and the more symptoms associated with low testosterone the more likely it is to work well.
In men with very severe symptoms, for example men who can’t achieve an erection at all, testosterone therapy probably won’t work well enough to bring their erectile function back to normal. These men may still benefit from testosterone therapy but there are likely to be other treatments that are also important for them.
What are the harms of testosterone therapy?
Overall testosterone therapy is well tolerated and most men will not be bothered by side effects or harms. There are some men where the risks of testosterone therapy are more likely to outweigh the harms and they are listed above.
Testosterone therapy harms are listed below:
- Acne may develop as a result of testosterone therapy or be made worse by testosterone therapy
- Male pattern hair loss can be a side effect of testosterone therapy, there are treatments available but this also means taking even more medication
- It can worsen or bring on some medical conditions like an enlarged prostate, obstructive sleep apnoea and heart failure
- Testosterone therapy suppresses the hormones that control the testes which can lead to testicular shrinking, this effect is dose dependent and is more common with injections
- Testosterone is naturally converted by the body to oestrogen which may cause breast development in men or gynaecomastia, this is also dose related and also more common with injections
- Testosterone is not very effective when given by mouth as a tablet and needs to be delivered either by injections or by applying a cream or gel. Injections may be slightly uncomfortable and contact with the cream or gel (e.g. after hugging a partner or children) can expose other people to the medication.
- It is unclear whether testosterone increases the risk of heart attacks and strokes as the available evidence is of poor quality and shows mixed results. It is also possible it may reduce the risk of heart attacks and strokes. Given the lack of agreement it is likely that whatever effect testosterone has it is likely to be small.
How is testosterone replacement therapy given?
Testosterone replacement can be given as an injection every 3 months or it can be applied to the skin in the form of a gel or cream every day.
Testosterone gel is applied first thing in the morning to the shoulders or upper arms after having a shower. It is important not to wash the site where the testosterone was applied for at least 5 hours after the application. The gel needs to be allowed to dry for a few minutes before putting on clothes. Some people find the amount of gel messy to apply and these people may prefer a cream.
Testosterone cream is made with exactly the same ingredient as testosterone gel but in a cream. It is also applied every day but it is applied to the scrotum (the skin covering a man’s balls or testes) instead of the upper body.
The injectable form of testosterone is typically given at 3 monthly intervals with frequency adjusted according to response on blood tests. It is often given more frequently in the beginning until the amount of circulating testosterone in the body levels out to reach what is called a steady state. This can result in testosterone levels that are somewhat higher or lower at different points over the three months but that are still mostly within the normal range. The main benefit is the convenience of not needing to take a medication every day.
What sort of monitoring and follow up is required?
Testosterone levels are typically checked every 3-6 months. Levels are checked more frequently in the beginning and with changing doses or method of delivery and less frequently when things are stable. This is also a convenient time for the patient and their doctor to assess for benefits and side effects.
A sensible approach is to trial treatment with testosterone for 3-6 months and continue if it is effective without serious side effects and stop the medication if it is not working as expected or if the side effects are not acceptable.