Testosterone replacement therapy

Key points about testosterone replacement therapy (TRT)

  • Testosterone replacement therapy (TRT) is a medicine prescribed by a doctor to treat low testosterone levels in men.
  • In some men with low testosterone, TRT can improve your mood, energy, wellbeing, libido and sexual function.
  • Find out how to use TRT safely and possible side effects.
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Note: The information on this page refers to the medical use of testosterone replacement therapy (TRT). It does not refer to the use of performance-enhancing steroids (sometimes called anabolic steroids), which are unregulated. Long-term use of performance-enhancing steroids can cause harm.

TRT is a medicine to treat the symptoms of testosterone deficiency (low testosterone levels), a condition called hypogonadism. In some men with low testosterone, TRT can improve your mood, energy, wellbeing, libido and sexual function.

TRT is testosterone given as a medicine prescribed by a doctor to treat the symptoms of low testosterone levels. It comes as a patch (Androderm), injection (Depo-Testosterone, Sustanon 250, Reandron) or capsules (Andriol). 

TRT is not for everyone. You need to have blood tests and a full discussion with your doctor to see if it is right for you. Read more about low testosterone levels.

TRT is a medicine prescribed by your doctor to treat testosterone deficiency to reach physiologic (natural) levels of the hormone in your blood.

Performance-enhancing steroids (sometimes commonly called anabolic steroids) are unregulated products that contain testosterone or chemicals that act like testosterone. They are sometimes used by bodybuilders and athletes. They contain these substances in higher doses and these are often combined with other chemicals that boost the overall muscle-building (anabolic) effect.

Long-term use of performance-enhancing steroids can cause harmful effects.

  • Injection: The TRT injection can cause swings in testosterone levels in some people. This can lead to fluctuations in mood and sexual behaviour, as well as breast tenderness and other symptoms. You will need to have follow-up blood tests. Make sure you have these on time, to check the dose is right for you. Before injecting TRT, warm the medicine to body temperature to reduce pain at the injection site. It is important that Reandron is injected slowly into a large muscle. 
  • Patch: You should avoid showering, swimming and sexual activity for 4 hours after putting on the patch. Skin irritation is common at the site of the patch.
  • Capsules: These are best taken with food.

TRT is used to treat testosterone deficiency (low testosterone) in some men. A low testosterone level by itself doesn't need treatment. TRT can have side effects, and the long-term risks and benefits aren't well known. 

Only men with symptoms of low testosterone and blood tests that confirm this should consider testosterone replacement. Men with testosterone levels in the bottom of the normal range (ie, still normal) are generally not treated with TRT. Read more about low testosterone levels.

The benefits of testosterone treatment can include improved mood, such as feeling less depressed, an overall feeling of energy and wellbeing, and improved libido and sexual function. TRT can also change your body composition, eg, give you more muscle mass and less abdominal fat.

If erectile dysfunction is the only symptom of low testosterone, TRT is unlikely to be used. A PDE5 inhibitor such as sildenafil is preferred, after other causes have been addressed. Read more about erectile dysfunction and PDE5 inhibitors.

TRT is should not be used if you have:

  • known or suspected breast or prostate cancer
  • liver tumours
  • high calcium levels (hypercalcaemia)
  • severe heart or kidney disease
  • untreated obstructive sleep apnoea.

Possible risks of testosterone treatment include:

  • decreased sperm production (if you want to improve your fertility, you should not use testosterone therapy)
  • a high red blood cell count, which can cause heart problems and blood clots
  • acne and oily skin
  • worsening of male pattern baldness
  • an increase in prostate size
  • unmasking or worsening of a pre-existing prostate cancer (but it doesn’t cause prostate cancer)
  • skin irritation of the area of the patch
  • pulmonary oil microemoblism (spread of oil droplets into your lungs) for Reandron injection 
  • testicular (ball) shrinkage on rare occasions with injections.

Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product(external link)

The following lifestyle changes can help you maintain a healthy level of testosterone:

  • lose weight if you are overweight
  • keep active and exercise regularly (but not vigorously)
  • get enough sleep (at least 7 hours per night)
  • don't drink too much alcohol
  • reduce stress. 

Do not use unregulated products that contain testosterone or chemicals that act like testosterone.

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Dr Jeremy Steinberg, FRNZCGP and Angela Lambie, Pharmacist, Auckland

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