Low testosterone, or "Low-T," is a surprisingly common condition that affects tens of millions of men around the world.
Testosterone is an essential hormone for men (and women, albeit in very small amounts). At healthy levels, testosterone is responsible for everything from controlling your sex drive and energy levels to helping you gain strength and develop muscle tissue.
It also has a range of effects on your brain, helping to make you feel more confident, assertive and masculine. Testosterone even affects things like your bone and heart health, making it an essential hormone not just for physical and mental performance, but also for general health.
There are numerous symptoms of low testosterone, ranging from lethargy to a decline in your physical strength. Below, we’ve listed the seven most common signs of low testosterone, all of which can indicate a potential testosterone deficiency.
We’ve also explained what you can do to treat your low testosterone, including testing options and common treatments for men with Low-T.
What to Do if You Have Low Testosterone
Low testosterone can occur for a variety of reasons. Sometimes, it’s a result of hypogonadism -- a male sex hormone deficiency that’s caused by issues in the testes (primary hypogonadism) or in parts of the brain responsible for controlling hormone production (secondary hypogonadism).
Since these parts of the body control testosterone production, even minor issues can cause a noticeable decline in your testosterone levels.
Testosterone production can also drop as a result of lifestyle and dietary issues. If you work in a stressful environment, don’t get enough sleep or eat a diet that’s lacking essential nutrients and vitamins, there’s a chance that these could affect your ability to produce testosterone.
The first step in treating low testosterone is verifying that your testosterone levels are actually lower than normal. Doctors that specialize in treating Low-T will usually do this using a blood test, which checks both your total testosterone and free testosterone levels.
The normal range for testosterone in men is 280 to 1,100 ng/dL. Most doctors consider a total testosterone level that’s either below or close to the bottom of the normal range to indicate low testosterone.
If either your free or total testosterone level is low, treatment options can range from changing your habits and diet to applying gels, patches or injections to bring your testosterone up to a healthy level.
The Seven Most Common Signs of Low Testosterone
Below, we’ve listed seven of the most common physical and mental symptoms that are used to diagnose low testosterone in men.
Because testosterone is a hormone with several functions, low levels can often result in multiple symptoms. If you’ve noticed several of the symptoms below, it’s best to talk to your doctor about getting a blood test to check your testosterone levels.
Testosterone is one of the primary hormones responsible for making you feel motivated, alert and energetic. When testosterone production is too low, it’s easy to feel fatigued and lethargic, even when you would normally be full of energy.
Low levels of testosterone are linked to chronic fatigue in men. If you often feel overly tired and lethargic, even after eating energy-rich foods or drinking coffee, there’s a chance that low levels of testosterone could be the culprit.
Smaller, Weaker Muscles
Testosterone is a powerful steroid, meaning it has a serious effect on your ability to gain muscle mass and improve your strength levels.
When your testosterone levels are low, it’s common for your muscles to shrink and your strength levels to decline. Worse yet, low levels of testosterone make it far more difficult than usual to get back the strength and muscular size you’ve lost.
Studies of testosterone show that it produces a 27% increase in muscle protein synthesis when administered to men. Simply put, the more testosterone your produce, the easier it becomes for your body to develop muscle.
If you’ve noticed your strength levels declining, the sleeves of your shirts fitting loosely or your progress stalling in the gym, it could be because of low testosterone production.
More Body Fat
As well as stimulating muscle growth, testosterone is also closely correlated with lower levels of body fat. People with high testosterone tend to be leaner; people with low testosterone usually have a higher body fat percentage, especially around the abdominals.
A study of men on androgen deprivation therapy, which involves reducing testosterone levels to almost zero, showed a 22% increase in visceral fat around the abdominals.
In simple terms, low testosterone will give you a little more weight around the midsection. It can also increase your risk of developing heart disease, as visceral fat can often collect around your organs.
Combined with muscle wasting, this can have a serious effect on your physique, making it worth getting your testosterone levels checked if you notice this symptom.
Low Sex Drive
Another common symptom of low testosterone is a weaker-than-normal sex drive. When your testosterone levels are low, it’s easy to lose interest in sexual activity, even in situations when you would normally be highly interested.
The sex drive effects of low testosterone affect sexual intercourse and masturbation, meaning you might not think about sex much at all. As you’d expect, this can have a major effect on your relationships and personal life.
Luckily, this symptom is usually the fastest to reverse when your testosterone levels get back to normal, meaning you should notice an improvement soon after starting treatment.
Testosterone triggers the release of nitric oxide, which is an essential molecule for developing and maintaining an erection. This means that when your testosterone levels are low, it’s more difficult to get and keep an erection than normal.
It can also mean that spontaneous erections -- the erections you get while sleeping, for example -- don’t happen anymore, or at least not as frequently as they normally would.
Since erectile dysfunction can occur for a variety of reasons, you shouldn’t rush to assume you have low testosterone if you have erection difficulties. However, combined with the other signs listed above and below, erectile dysfunction could be a sign of a testosterone-related issue.
Testosterone is responsible for more than just physical effects; in men, it affects a huge range of brain functions, including memory. In fact, one of the most noticeable effects of low testosterone in men is "brain fog," or a general decline in memory and focus.
One study of men aged 70 years and above shows that age-related decreases in testosterone levels were closely correlated with cognitive decline. As testosterone levels declined, men were more likely to suffer from negative effects on cognitive functions such as memory.
This doesn’t mean that forgetfulness is a sure-fire sign of low testosterone. However, if you’ve noticed a decline in your memory, it could potentially be a signal that your testosterone level is lower than it once was.
Finally, testosterone levels are closely correlated with confidence, mood and general quality of life for men of all ages.
One study from 2012 shows that treatment naïve hypogonadal men (men with low testosterone levels that did not seek treatment) showed more severe symptoms of depression, anxiety, poor quality of life and sexual dysfunction than similar men assigned to a testosterone treatment.
Other studies show similar results -- that testosterone improves mood by a significant amount in men, with measurable decreases in negative emotional responses such as anger, irritability, and nervousness.
As always, a poor mood doesn’t necessarily mean you have low testosterone. However, if you frequently feel tired, irritated, anxious or depressed and also have some of the other symptoms of low testosterone, it could be worth getting your testosterone levels checked.
Should You Check Your Testosterone Levels?
Many of the symptoms above can occur without being caused by a testosterone deficiency. For example, it’s normal to feel tired or frustrated sometimes, especially if events in your personal or professional life have an effect on your mood.
It’s also normal to occasionally feel physically weaker than you normally would, especially if you make a change to your diet, lifestyle or physical activity levels.
As a general rule, you should consider getting your testosterone levels checked if you notice any of the symptoms listed above occurring frequently enough that you feel they aren’t just a normal occurrence.
Checking your testosterone levels is a quick and simple process. Most of the time, your levels can be verified with a simple blood test that measures your free testosterone, total testosterone, and other hormones.
This article was reviewed by Ho Anh, MD.