Low testosterone, or low-T, occurs when men produce testosterone below the normal range of 300 to 1000 nanograms per deciliter. It is a pervasive challenge for men, particularly as they get older. It is estimated that 40 percent of men who are 45 years old or older have low-T. Science is beginning to reveal that symptoms once thought to be part of the normal aging process may instead be a result of low-T. While healthcare providers can perform serum tests to determine a man’s precise level of testosterone, there are some key ways that men can discover on their own that they likely have low-T.

The Androgen Deficiency in the Aging Male (ADAM) questionnaire is a screening tool that has been widely used to test for androgen deficiency. Men who are androgen-deficient are low in male sex hormones, particularly testosterone. Research has shown that men’s performance on the questionnaire correlates with their serum testosterone levels, which suggests that the questionnaire can be used both as a screening tool and as a diagnostic tool.

Men who suspect that they have low-T can use this tool to determine from home how likely they are to actually be experiencing low-T. If the questionnaire indicates that someone is like to have low-T, that person should follow up with a healthcare provider to get their testosterone levels checked and determine a course of action for addressing their low-T symptoms and any underlying causes for the reduction in low-T if appropriate.

Produced in the male testicles, testosterone is a male sex hormone that contributes to sexual development and functioning. While age is one important risk factor for low-T, according to the American Urological Association, weight is another factor that enhances the risk of low-T. Research has shown that 30 percent of overweight men have low-T, while only 6.4 percent of men who are normal weight have low-T. Another study showed that 24.5 percent of men with diabetes, which is linked to obesity, had low-T, whereas only 12.6 percent of men without diabetes had low-T.
All men are at risk for low-T, but men who are overweight and older are at a higher risk and should more regularly consider whether they are experiencing any of the symptoms of low-T. Below are the main symptoms that are addressed through the ADAM questionnaire and information to help with the assessment of whether such symptoms may indicate low-T.

Libido, Energy, Strength/Endurance, Height, Enjoyment of life, Sad/Grumpy, Sexual Function, Sports, Tiredness, Work

Do you have a decrease in libido (sex drive)?

Studies have shown that compared to men who report normal or high libidos, men who report low libidos are more likely to have low-T. Because testosterone is involved in sexual functioning, low levels of this hormone are associated with lower sex drives, and a reduction in this hormone can lower one’s sex drive. When you are trying to determine whether the status of your libido may be a sign of low-T, you should think about any relative changes in your libido. If you have never had a high libido and your libido has stayed the same, it is less likely that your low libido is a sign of low-T than if you now have a lower libido than you have in the past. A drop in libido can be an indication of a corresponding drop in testosterone levels.

Do you have a lack of energy?

When low-T patients discuss the changes that low-T has on their quality of life, the things they deem most important are the impairments in their sex life and the reductions in their energy levels. Men with low testosterone levels are more likely to suffer from fatigue than those with normal levels of testosterone, and Low-T can lead to chronic fatigue. While fatigue can occur in men for a variety of reasons, low energy levels combined with a reduction in sex drive or sexual functioning may indicate low-T.

Do you have a decrease in strength and/or endurance?

Reduced strength, endurance, or stamina can be a sign of low-T. Testosterone directly affects muscle through the attachment to specific receptors. For instance, testosterone increases muscle protein synthesis, which is an important process for building and maintaining muscle mass and strength. Men with low-T have been shown to have decreased muscle mass. Muscle mass can decrease because of less frequent or less serious use of muscles as well, but if muscle mass decreases in the absence of a change in muscle use, low-T could be the cause.

Have you lost height?

Though losing height is more weakly associated with low-T than the other signs and symptoms addressed through ADAM, getting shorter can be a sign of low-T. Height has been shown to be positively correlated with both total testosterone levels and free testosterone levels, which suggests that testosterone contributes to growing taller. If a man notices that he is losing height, he should consider whether he has other signs of low-T. Stunted growth or shrinking height combined with other classic signs of low-T could indicate that someone is in fact experiencing low-T.

Have you noticed a decreased “enjoyment in life”?

When men feel that they are not enjoying life as much as they once did, low-T is one potential cause. Low levels of testosterone tend to make men feel lethargic and unhappy and are linked to depressive disorders. The precise mechanism by which reduced testosterone may lead to depression is not clear, but it is likely that the other effects of low-T are at least partially responsible. In other words, several of the symptoms associated with low-T, such as sexual dysfunction and reduced energy, can themselves adversely affect mood and subjective evaluations of quality of life. Thus, if someone notices that they are enjoying life less than they once did, and they also have other symptoms of low-T, they should more thoroughly evaluate whether they could have low-T.

Are you sad and/or grumpy?

Just as the effects of low-T can cause depression and make men feel sad, they can also lead to grumpiness, anger, and frustration. Low-T has in fact been shown to be linked to mood and behavior-related changes. Using testosterone therapy has been shown to improve sadness and grumpiness in low-T men, but whether it does so directly or by improving other symptoms that lead to a better quality of life is unclear. Nonetheless, if someone notices that they are sad or grumpy, particularly without a situational context that is normally conducive to these emotions, that person should consider whether they could have low-T.

Are your erections less strong?

Low testosterone is a known cause for erectile dysfunction, so men experiencing weaker erections or other types of erectile dysfunction could have low-T. It is clear that erections depend on sex hormones like testosterone. As such, men with erectile dysfunction who are treated with testosterone replacement therapy experience improvements in the strength of their erections. Men who suddenly experience erectile dysfunction or notice that their erections are less hard should consider whether low-T could be the reason for these changes.

Have you noticed a recent deterioration in your ability to play sports?

Like with many other symptoms of low-T, if a man has never been particularly good at sports, his lack of sports ability is likely not a sign of low-T. However, if a man experiences a reduction in sports ability, it could indicate a change like lowered testosterone. One way that low-T can lead to poorer sports performance is through its effect on muscle mass, strength, and endurance. As these abilities dwindle, sports performance tends to decline. Men experiences a deterioration in sports ability should think about whether they have other signs of low-T.

Are you falling asleep after dinner?

Feeling tired or falling asleep early can be a sign of low-T. Low testosterone may lead to chronic fatigue and sleepiness by reducing the overall quality of sleep so that men with low-T are not experiencing sufficient sleep to be well-rested. Being more tired than usual can be due to a wide range of issues ranging from stress to other medical conditions. However, men who notice that they are chronically tired and who also experience other symptoms of low-T should explore whether they may have low-T.

Has there been a recent deterioration in your work performance?

A deterioration in work performance, particularly if linked to cognitive functioning, could be a sign of low-T. For instance, low testosterone is a risk factor for worse cognitive functioning in elderly men and even increases the risk of Alzheimer’s disease in this population. Low-T is associated with memory deficits, which can account for problems in work performance. Work performance can also be hindered by other symptoms of low-T such as depressed or agitated mood. Men who notice that they are not performing as well at work should always consider the source of the problem. If the source is consistent with one or more symptoms of low-T, then it could be that work is suffering due to low-T rather than some other factor.