Testosterone is a sex hormone (androgen). It’s called a “male” hormone, but women also produce it in much lower amounts. Testosterone is essential for your sex drive (libido), bone and muscle health, mood, and cognitive function. If your testosterone levels are low, your doctor might prescribe TRT.

What’s testosterone replacement therapy? 

TRT is one of the treatment options for men with low testosterone levels (hypogonadism).

TRT restores your testosterone levels to fall in the normal range. It helps treat the symptoms and long-term effects caused by low testosterone.

It comes in various forms — like injections, gels, capsules, or testosterone patches. And your doctor will always consider your preference.  

Some men have hypogonadism from birth, which can lead to delayed puberty and small testes. This condition can also develop later in life — particularly if you’re obese or have type 2 diabetes

Hypogonadism is common in men, and there are many causes. It’s important to rule out all causes before starting TRT. In the UK, an endocrinologist (hormone specialist) performs many tests before prescribing TRT.

What are the normal ranges for testosterone?

It’s important to remember that testosterone levels fluctuate throughout your life. 

Men’s testosterone levels are typically stable after puberty, declining by under 2% annually from age 30 to 40. And in women, testosterone levels fluctuate monthly after puberty — reaching their highest levels mid-way during the menstrual cycle. Because of these differences, there are separate guidelines for men and women. 

The normal ranges for testosterone, if you’re under 50, are:

  • men — 8.64 - 29 nmol/L
  • women 0.29 - 1.67 nmol/L

The normal ranges for testosterone, if you’re over age 50, are:

  • men — 6.68-25.7 nmol/L
  • women — 0.101-1.42 nmol/L

Check to see if your testosterone levels fall in the normal range by using a home testosterone blood test

You should do this blood test early in the morning — when your testosterone levels are most stable, giving you accurate results. You should also fast (not eat or drink anything except for water) for 8 hours before your test.

Can women get TRT?

Most women won’t need TRT as they produce testosterone in much lower amounts. But there are some exceptions. For example, your doctor might prescribe TRT to help increase your libido after menopause.

You can check your risk factors for certain conditions with a menopause insights blood test.

How to get TRT

You might benefit from TRT if your body doesn't make enough testosterone.

If you’re experiencing low testosterone symptoms, discussing these with your GP is essential so they can rule out any other conditions. They’ll also consider your diet and lifestyle when investigating your symptoms. 

Take the first step by doing a testosterone blood test at home. If you’re a man with low levels, your doctor might refer you to an endocrinologist (a hormone specialist) to investigate your symptoms further.

You should see your GP if you have the following symptoms: 

  • fatigue
  • depression or anxiety
  • irritability
  • low libido
  • erectile dysfunction (ED)
  • reduced exercise tolerance and strength
  • excessive sweating and night sweats
  • poor concentration or memory
  • needing to shave less often 

Your doctor might recommend lifestyle changes if these contribute to low levels. Lifestyle changes might be combined with TRT depending on the cause. 

What are the benefits of TRT?

TRT is given to help improve physical and mental symptoms associated with hypogonadism. 

TRT might help improve:


  • body composition — the percentages of fat, bone, water, and muscle in your body
  • sex drive and performance 
  • muscle strength
  • mood
  • depression 
  • insulin resistance — if you have type 2 diabetes

TRT also reduces your risk of developing osteoporosis. This is because normal testosterone levels help to support bone strength. 

Your GP will regularly measure your testosterone levels to check that TRT is safe and effective. It’s also important to remember that TRT might not work for everyone.

What are the risks of TRT?

As with any medication, there are some risks associated with TRT. 

For example, it might cause increased levels of:

  • haemoglobin — a protein found in red blood cells
  • haematocrit — the ratio of the volume of red blood cells to the total volume of blood

Both of these combined indicate thickening of your blood. This might increase your risk of heart attack, stroke, and blood clots. The good news is your blood is tested before and during TRT treatment to monitor your haemoglobin and haematocrit levels. 

TRT can also cause an enlarged prostate or other prostate disorders. Before treatment, you’ll be screened for prostate disease with a physical examination and a prostate-specific antigen (PSA) test. During treatment, PSA is measured again to check for any changes. This is particularly important in men over age 50. 

If you’ve had prostate cancer in the past, you won’t be suitable for TRT (unless you had your prostate removed).

Other side effects may include: 

  • weight gain
  • increased appetite
  • hot flashes
  • acne
  • depression
  • restlessness
  • irritability
  • aggression
  • tiredness
  • weakness
  • excessive sweating

As a result of TRT, your natural production of testosterone may be reduced. This may also lead to a reduction in sperm production. So if you’re considering having children in the future, you should discuss this with your healthcare professional before starting treatment.

TRT might be the right choice if you’re suffering with the accompanying symptoms. But it’s important to weigh up the benefits, risks, and types of TRT with your doctor to support your quality of life.

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