Low testosterone symptoms

Worried you may be suffering from low testosterone? Here’s everything you need to know about the symptoms to look out for.

Dr Chris Airey

Medically reviewed by Dr Chris Airey

BMBS MMedSc Dip ENDO, TRT Expert

Last Updated December 23, 2023

What is testosterone?

Although we tend to think of it as the thing in charge of all things ‘male’, testosterone is a hormone that is found in both men and women. In men, testosterone is produced in the testicles in response to hormones released by the brain’s pituitary gland. It supports sperm production and sex drive, and regulates muscle and bone mass, fat distribution, facial hair, energy levels, and even your mood. It’s important stuff.

In women, testosterone is produced by the ovaries at lower levels than in men. It supports the growth, maintenance and repairs of female reproductive tissues, bone mass and also contributes towards their libido.

Dealing with the physical and mental symptoms of low testosterone, aka ‘low-T’ or hypogonadism, can really take its toll. We’ll delve into the symptoms to look out for, the diagnostic process, and the available treatment options.

Understanding low-T

Testosterone levels peak during your late teens and naturally start to decline by roughly 1 to 2% each year once you hit 30. However, scientific studies show that 1 in 4 men over the age of 30 may have chronically low testosterone levels. 

‘Normal’ testosterone levels can vary widely from person to person, but levels of total testosterone lower than 15 nmol/L (that’s nanomoles per litre of blood) or free testosterone lower than 225 pmol/L (picomoles per litre) may require treatment.  

Lifestyle factors such as alcohol intake, being overweight and lack of sleep can accelerate the deterioration of testosterone levels. Certain medical conditions including diabetes, liver or kidney disease, obesity, pituitary gland problems, thyroid problems, HIV, AIDS, as well as side effects from chemotherapy can also affect levels. Sometimes, however, testosterone levels may drop without a clear cause.


Symptoms of low testosterone

When testosterone levels are below the healthy range, it can have wide-ranging implications that affect a lot of bodily functions. If you think you may be suffering from low testosterone, you may have noticed one or several of the following symptoms.

Erectile dysfunction (ED)

Since erectile dysfunction can occur for a variety of reasons, it doesn’t necessarily mean that you have low testosterone. The link between ED and low testosterone is complex and isn’t yet fully understood. However, research shows that low testosterone levels can affect your sexual function, and a low sex drive can contribute to issues like ED. Evidence also suggests that testosterone triggers a chemical reaction in the brain that results in achieving and maintaining an erection. So, if you have difficulty with this, there’s a chance that it’s because your testosterone levels are low. 1

Clinical studyThis study found that testosterone undecanoate therapy restored normal testosterone levels in hypogonadal men with impotence and improved sexual function and wellbeing in 61% of cases. Clinical outcomes, rather than standard biochemical measures, were more indicative of treatment success.

Sexual dysfunction & infertility

Symptoms of sexual dysfunction such as a complete loss or significant reduction in your sex drive and smaller, softer testicles can also be indicators of low testosterone. Your body’s ability to produce sperm is also affected by low testosterone, potentially resulting in a reduced sperm count and, in some cases, even infertility.2

Clinical studyThis study explores how low levels of testosterone in men can negatively impact spermatogenesis, resulting in reduced sperm count and motility – both of which are critical factors for fertility.

Weight gain & loss of muscle mass

An increase in body fat, especially in the breast area, can be a sign of low testosterone levels. If you feel like your breasts are swelling, this might be a condition known as gynecomastia. While this is a symptom of testosterone deficiency, it can also indicate an imbalance of oestrogen levels. 

Testosterone plays an important role in building and maintaining your muscle mass. If you have a testosterone deficiency, you could experience a decrease in muscle mass which could make exercising more tiring than before. This doesn’t necessarily translate to a loss of strength, however.3

Clinical studyThe study evaluated the effect of testosterone replacement therapy (TRT) on muscle mass and protein synthesis in five men with low-T. After six months of treatment, there was a significant increase in muscle mass (20% on average) and fat-free mass (15% on average), with a simultaneous decrease in fat mass (11% on average).TRT also led to a 56% increase in the rate of muscle protein synthesis. These results suggest that TRT can substantially enhance muscle mass in hypogonadal men by promoting protein synthesis within muscles.

Decreased bone density

Testosterone promotes healthy bones. Low-T can increase the risk of developing osteoporosis, a condition characterised by a low bone mineral density. This condition is also associated with the normal ageing process, so it might not be a direct result of low testosterone levels.4

Clinical studyThis study suggests that age-related decreases in testosterone contribute to the loss of bone density, as well as muscle mass and strength.

Fatigue & difficulty sleeping

Low testosterone can affect your sleep quality. If you’ve previously suffered from insomnia or sleep apnea, you may find your sleep pattern worsens even further. If not, you may suddenly have difficulty sleeping well or you might feel tired even when you’re well rested. You may also notice that you don’t have the energy to perform daily tasks that you’re used to. A prolonged lack of interest in exercise or physical activity, especially in previously fit men, can be an indicator of low testosterone levels.5

Clinical studyThis study showed that testosterone replacement therapy significantly improved energy levels, alongside mood and wellbeing, in men experiencing low testosterone over a 60-day period.

Mood Swings & depression

A lack of focus, depression and general irritability are a few of the symptoms of low testosterone that affect your mental wellbeing. A prolonged period of low mood and lack of enthusiasm may be an indicator of hormonal imbalance too.6

Clinical studyThis study shows that men with low testosterone are more likely to be diagnosed with depression than those with normal levels, even after considering other health and lifestyle factors. Further research is needed to explore how testosterone could be used in treating depression within this demographic.

Check your symptoms today

Take a quick online assessment to see if your symptoms are related to low testosterone and if you are suitable for treatment.


Diagnosing low testosterone

Our TRT doctors will conduct a comprehensive diagnosis so that they can design a personalised, sustainable protocol for you which results in real improvements. 

The process starts with an initial finger-prick blood test which you can take at home. This measures 4 biomarkers including your total and free testosterone levels. You’ll be able to access your results within 48 hours via your MANUAL account.

If the results of your first test indicate low testosterone levels, UK regulations require a second, more comprehensive venous blood test to be taken (by a nurse or phlebotomist) before you can start TRT. This measures 43 biomarkers, confirms the initial blood test result, and will tell us more about your health including any possible underlying conditions.

You’ll then have an in-depth consultation with one of our TRT doctors where they’ll discuss your medical history and lifestyle, your blood test results, your symptoms, the risks and benefits involved in TRT, treatment options (including costs), monitoring, and what to expect when you start treatment.

Finally, your doctor will design a personalised treatment plan that works specifically for you, including the right medication at just the right dose to suit your individual needs. 

Treating Low Testosterone

There’s no one-size-fits-all treatment protocol for low testosterone, as each person’s experience with low-T is entirely unique. There are a lot of physiological and genetic factors which affect how each person responds to different treatments, plus your lifestyle has to be taken into careful consideration when choosing the right protocol. 

Our doctors will design a personalised, bespoke treatment that works specifically for you. Successful hormone therapy involves getting just the right dose by the right delivery method for your individual needs. You’ll have the option of taking prescribed testosterone medication in the form of injectable, oral, or topical treatments. Once you start treatment, your doctor will monitor your progress and make incremental adjustments to your protocol to ensure that your body gets the right amount of testosterone to put your levels within a healthy physiological range

Worried about your testosterone levels?

Low testosterone is an overlooked but common problem for men. If you think you might be suffering from its symptoms, the good news is that it can be treated successfully. Talk to a doctor or take our simple at-home blood test to check your testosterone levels and find out if you may benefit from treatments – the effects could change your life.

Disclaimer: This content is not a substitute for professional medical advice. You should consult a healthcare provider for a full diagnosis and advice about low testosterone.