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What are the signs of low testosterone?

Common misconceptions about low testosterone is that it only causes muscle loss or low libido, or that it only affects men. In reality, it’s much more complex than that.

This guide will go through the full range of physical and mental symptoms that can be linked to low testosterone in both men and women, as well as how they can impact your day-to-day life.

Medically reviewed by

Sanjeda Chowdhury, Superintendent Pharmacist + Independent Prescriber

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Reviewed on Jul 15, 2026. by Ms Sanjeda Chowdhury Superintendent Pharmacist + Independent Prescriber Registered with GPhC (No. 2202465) Next review due on Jul 15, 2029.

Last updated on Jul 17, 2026.

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Physical signs

Low testosterone (sometimes called Low T, testosterone deficiency or male hypogonadism) happens when the body does not produce enough testosterone. In men, testosterone is mainly made in the testicles. It’s fairly common, particularly as men get older, with 20% to 50% of men over the age of 60 having significantly lower T levels than younger men.

Although testosterone is typically associated with men, women produce it in their ovaries and adrenal glands (two small glands that sit on top of each kidney), too. Testosterone levels gradually decline with age and after the menopause. For some women, this may contribute to symptoms such as a lower sex drive or tiredness, although many other conditions can cause these symptoms too.

Low-T can affect overall health, causing a series of physical symptoms, including:

Extreme tiredness

Although fatigue can have many causes that have nothing to do with low testosterone, feeling tired despite getting a normal seven or eight hours of sleep is a common symptom of low-T. And if you’re wondering whether it’s just everyday tiredness or something more, one clue is that testosterone-related fatigue is often accompanied by other symptoms, like lack of motivation, loss of muscle mass, difficulty concentrating, low mood, and even depression.

This is because when your testosterone drops below normal levels, it can change how your cells produce and use energy and leave you feeling constantly drained.

Weight gain

If you feel like you’ve been gaining belly fat or developing enlarged breast tissue, even if you exercise regularly, this could be another sign that your testosterone levels are low. Clinical trials have found that testosterone replacement therapy (TRT) potentially can reduce body fat, especially around the middle of your body (the trunk).

In both men and women around or after menopause, low testosterone levels can contribute to a loss of muscle mass. And because muscle burns more calories than fat, having less muscle can slow your basal metabolism over time, making you more prone to accumulate stubborn fat, particularly around your abdomen.

Hair loss

Testosterone itself isn’t directly linked to hair loss. However, your body’s sensitivity to a hormone called DHT, which is linked to testosterone, is. Here’s how it works.

There are two types of testosterone in the body: bound and free testosterone. Most of the testosterone in the body is bound to proteins in the blood, while only 2% to 5% of it is free. The free T (not the bound form) can be converted into dihydrotestosterone (DHT) in your body. DHT then binds to receptors on your hair follicles on your scalp, face, and the rest of your body. Over time, this causes them to become thinner and shorter, and can eventually lead to hair loss.

For women, if your follicles are more sensitive to DHT, hair loss is more likely to start around menopause, when hormonal changes can make the effects of DHT more noticeable.

Low libido

Low-T can reduce sex drive (libido) in both men and women. However, libido is influenced by many factors, including age, your relationship with your partner, what medications you’re taking, and your overall physical and mental health. So, if you’re experiencing low libido, low testosterone may be one of several possible causes rather than the only explanation. Yet, many studies have shown that testosterone replacement therapy (TRT) can improve libido in some men and women with low testosterone levels.

Erectile dysfunction

Low-T can contribute to erectile dysfunction (ED), but it’s usually not the sole factor. While TRT has been shown to improve mild ED, it’s generally less effective for more severe cases. However, TRT has been shown to help improve erectile function in men who haven’t responded well to PDE-5 inhibitor medications like sildenafil and tadalafil.

Loss of muscle mass

This is one of the late signs of low-T, and is also sometimes called muscle wasting. It happens because on the surface of muscle cells there are receptors for testosterone. When testosterone levels are low, muscle tissue may start to break down and gradually lose function.

Mental signs

Aside from physical symptoms, low-T can also affect how you think and feel. Here are some of the psychological and cognitive changes that may be associated with low-T:

Mood changes

Low-T can contribute to difficulty concentrating, feeling irritable, anxious, depressed, and in some cases suicidal thoughts. . You might find yourself more easily irritated by things others do or say, show a lower level of interest in activities you once enjoyed, or you may find it harder to cope with everyday stress.

Low motivation

Testosterone is involved in brain pathways linked to motivation, reward, and emotional regulation. So, if you have testosterone deficiency, you may find it harder to get started on tasks, feel less enthusiastic about work or hobbies, or notice that activities you once enjoyed no longer feel as rewarding. That said, these symptoms can also be caused by many other factors, including stress, poor sleep, and depression.

Brain fog

Brain fog is used to describe when you feel that your thinking isn’t as sharp as normal. You may also feel more forgetful or less able to concentrate.

Testosterone receptors are found throughout the brain, including areas that play a role in cognition and memory. Although testosterone’s effects on the brain are still incompletely understood, changes in testosterone levels can trigger difficulties with concentration, memory, and mental focus in some people.

Heightened anxiety or depression

Low-T can affect your emotions as well, leading to feelings of sadness that can eventually develop into depression. Research, however, has found that both high and low testosterone levels were linked to depressive symptoms compared with men with normal testosterone levels. . This means changes in mood are not always explained by testosterone levels alone.

Mental exhaustion

Mental exhaustion is not specific to low testosterone. Sleep problems, chronic stress, mental health conditions, and other health issues can all cause similar symptoms. That said, some people with low-T describe feeling like everyday tasks require more effort, struggling to stay focused, or finding it harder to cope with stress.

How common is it to miss signs of low testosterone?

It’s very common to overlook signs of low-T, as its symptoms can easily be mistaken for stress, burnout, or simply getting older.

Another reason is that symptoms rarely show up all at once. Testosterone levels typically decline gradually, so changes tend to develop slowly. Because of this, it’s easy to dismiss them as a normal part of ageing or adapt to them without realising how much they’ve affected your day-to-day life.

When do testosterone levels begin to drop?

Testosterone levels naturally drop approximately 1% each year after the age of 30. While ageing alone doesn’t determine whether someone will develop symptoms or not, a severe or sudden drop will cause symptoms.

It’s worth mentioning that other factors aside age, like obesity, poor sleep, chronic illness, medications, and lifestyle can also influence testosterone levels.

While women naturally produce much smaller amounts of testosterone than men, T levels tend to drop during the transition to menopause and after menopause, as the hormone production in the ovaries decreases. Testosterone levels can also plummet after a hysterectomy (surgery that removes the womb), if the ovaries are removed at the same time.

How and when should I check my testosterone levels?

If you’re experiencing symptoms that may be linked to low-T, for example ongoing tiredness, low sex drive, loss of muscle strength , mood changes, or difficulty concentrating, it may be worth discussing testing your testosterone levels with a healthcare professional.

They may recommend measuring testosterone levels with a morning blood test for men (since T levels are usually higher in the morning) and confirming low results with repeat testing before making a diagnosis.

How can I treat low testosterone?

The best approach depends on what’s causing low testosterone. Lifestyle changes like good sleep hygiene, avoiding alcohol, maintaining a healthy weight, and exercising can help support healthy testosterone levels. This is especially when low testosterone is linked to factors such as excess body weight, poor sleep, or low levels of activity.

For some people, these changes may significantly improve testosterone levels on their own. However, when your testosterone levels remain low despite lifestyle changes, or when there’s an underlying medical cause behind it, it’s best to discuss what the best treatment is for you with your clinician. They might recommend medications like testosterone replacement therapy.

Medication to help increase low testosterone

Experiencing symptoms of low testosterone doesn’t mean you have to accept them as a normal part of ageing. If blood tests confirm that you have testosterone deficiency, your clinician may recommend treatments that can help restore your hormone levels and improve your symptoms.

Testosterone replacement therapy has been shown to improve symptoms such as sexual function, muscle mass, mood and depressive symptoms. It’s available as gels, patches, injections, tablets, or pellets implanted under the skin. Your clinician can help you decide which one is best for you.

For women, TRT is usually prescribed off-label to menopausal women if hormone replacement therapy (HRT) alone hasn’t been effective for low libido. Apart from improving sexual function, some studies have also found that TRT potentially can improve or maintain bone density and muscle mass, and help with mood, concentration, and energy levels.

TRT isn’t the right option for everyone, which is why it’s important to speak to a healthcare professional. They can assess whether it’s suitable for you by looking at your symptoms, blood test results, medical history, and weighing up the potential benefits and risks.

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