Men’s Health A-Z

Low Testosterone

Frequently asked questions about low testosterone in men that are answered by a doctor. What are the symptoms? What causes it? How do you fix it?

Medically reviewed by:

Dr. Ryan Flannigan
Dr. Ryan Flannigan

MD, B.Sc.

Low Testosterone

What is Low Testosterone?

Men produce testosterone primarily in their testicles. The Leydig cells in the testicles produce testosterone. There is also a very small amount of testosterone produced from the adrenal glands. 

Typically, this testosterone exists within a range in our body between roughly 8.5 units to 29.5 units in Canadian laboratories. When total testosterone levels drop below this, we’re considered to have low testosterone. We are also considered to have low-normal or borderline testosterone between the 8.5- and 12-unit mark in Canadian labs. 

The clinical diagnosis of low testosterone is when somebody with borderline or low testosterone (so less than 8.5 units) and they’re symptomatic. 

Signs & Symptoms


There are a lot of different potential causes for low testosterone. Oftentimes, we can’t explain why testosterone is low, and this is referred to as idiopathic. 

There does not appear to be any conclusive evidence that low testosterone is hereditary. However, this is not greatly understood, and more research is needed. 

The list of potential causes is long and includes:

  • Trauma or injuries to the testicles 
  • Infection to the testicles called orchitis
  • Chemotherapy can damage some of the cells in the testicles
  • Alcohol abuse
  • Obesity
  • Ageing
  • Obstructive sleep apnea
  • Some medications
  • Poor sleep or shift work

Can testicular cancer cause low testosterone?

Men with testicular cancer will also have low testosterone. This could be due to dysgenesis of some of the testicular cells, meaning that some of the testicular cells didn’t form normally, which led to testicular cancer. This can present as either low testosterone or infertility. 

If you have had one testicle removed due to cancer, you are at an increased risk of low testosterone in the future. Many men will have normal testosterone with one testicle, but it does put them at increased risk as they age.

When testicular cancer patients undergo radiation therapy, this increases the risk of low testosterone, particularly if there’s not adequate shielding of the remaining testicle. If patients undergo chemotherapy, this puts them at increased risk of low testosterone, depending on which chemotherapeutic agent is used.

Some patients have more or less risk, but all testicular cancer patients should have testosterone drawn or monitored at some point in time. 

Can a vasectomy cause low testosterone?

No. In a vasectomy, the vas deferens tube transporting sperm is cut and blocked. This is completely independent of how testosterone is made. Testosterone is made inside of the testicle by the Leydig cells, which then distribute testosterone into the blood.

Are there foods that cause low testosterone?

Some studies have suggested that a high intake of bread, pastries, dairy products, desserts and processed foods, and low intake of homemade foods (good sources of vegetables or healthy sources of cholesterol and Omega-3) can be associated with lower levels of testosterone production.


There are lifestyle changes you can make to improve testosterone production. These include maintaining a healthy weight, exercising, eating healthy foods, and getting proper sleep.

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Get Active

Exercise can help prevent low testosterone by helping to maintain and optimize the natural production of testosterone. Resistance exercises or combinations with some aerobic exercise can be helpful, as well as maintaining lean body mass. Low levels of fat and high levels of muscles can also encourage the maintenance of higher natural levels of testosterone. 

However, excess aerobic exercise can suppress the hypothalamus and the pituitary gland. This means less LH is sent to the testicle, the hormone that tells the Leydig cells in the testicle to make testosterone. The absolute amount of aerobic exercise varies from person to person; this is similar to when females are exercising too much and lose their menstrual cycle.

Overall, exercise is very helpful, though extreme high volumes of aerobic exercise can lead to lower testosterone levels. 

Eat Healthier

Healthy eating is an important factor in maintaining a healthy body weight. The literature around whether a specific diet can help prevent low testosterone is fairly weak. Most studies are association studies or animal studies. We do know that maintaining lean muscle mass, having low-fat stores within reason, regular exercise, and healthy eating are important for producing testosterone. 

A healthy diet includes a good balance of carbohydrates, proteins, healthy fat sources such as Omega-3s, and healthy sources of cholesterol. 

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Sleep Better

Good sleep hygiene can help prevent low testosterone. Getting healthy and regular sleep has been associated with better testosterone production levels.

Shift work and disrupted sleep in the middle of the night have been associated with lower testosterone levels.

Drink Less

Moderate alcohol consumption or cutting out drinking entirely likely can’t prevent low testosterone. However, drinking smaller amounts or no alcohol compared to excessive drinking habits will help maintain normal testosterone levels.

Drinking excessive amounts of alcohol has been associated with lower testosterone production. 

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Signs & symptoms

The signs and symptoms of low testosterone can be broad and non-specific, meaning they can overlap with many other situations or medical conditions. 

Common Symptoms

Low Testosterone: 

  • Decreased energy 
  • Decreased exercise tolerance 
  • Decreased ability to develop muscle 
  • Decreased ability to lose fat tissue 
  • Decreased mood 
  • Decreased concentration or increased fogginess of mental clarity
  • Decrease sex drive or libido
  • Decreased strength
  • Increasing body weight or fat
  • Absence of morning or nighttime erections

Very Low Testosterone: 

  • Hot flashes
  • Decrease in body hair, distribution or growth 

Diagnosis & Treatment


The best way to test for low testosterone is through your primary care doctor and having your morning total testosterone level checked. This means that your blood will be drawn within the first two to three hours upon waking up in the morning. This should be repeated for a second time if it is abnormal the first time. 

If the blood testosterone levels are low and a person is symptomatic, then these individuals might be a candidate for consideration of testosterone therapy. Candidates for this therapy should recognize that it is typically a chronic lifelong therapy and should not be implemented in patients that are considering fertility as it will likely stop sperm production. 

There are other ways to test for low testosterone beyond total testosterone levels. There are free testosterone levels, measurements of sex hormone-binding globulin or SHBG, and measurement of albumin levels. With this information, bioavailable testosterone can be calculated. Literature is controversial concerning which test is the best to predict symptoms and status of low testosterone. Therefore, total testosterone is often most reliably used and easiest to acquire. 


If you have low testosterone, a healthy lifestyle that includes regular exercise, good sleep, and a healthy diet is recommended to promote the natural optimization of testosterone production and to maintain healthy body weight. If testosterone levels are still low even with healthy lifestyle changes, then medications can be considered.

There are typically two patient populations:

Men who desire potential fertility in the future:

For this group, exogenous forms of testosterone therapy cannot be used. This is because they will shut down sperm production by suppressing the hypothalamus and pituitary glands, which then suppress the testicle from testosterone production. In these individuals, medications such as clomiphene citrate or aromatase inhibitors (such as Anastrozole) are sometimes recommended. In very specific situations where people have an abnormality of their pituitary or hypothalamus glands, HCG injections may be used.

Men who do not desire future fertility:

Where fertility is not a consideration, testosterone formulations are generally either injections or transdermal:

  • Transdermal might include testosterone gels that can be applied to the armpits or the shoulders and upper arms each day, or testosterone patches can sometimes be used.
  • Different formulations of testosterone injections are typically injected every one to three weeks.
  • Testosterone pellets can be placed under the skin with a small procedure and can produce a slow release of testosterone over many months. 

A newer drug to the market likely to come to Canada soon is an intranasal testosterone gel that is absorbed rapidly. So far in a clinical trial, it has shown less suppression on the pituitary and hypothalamus glands, and therefore less disruption to sperm production. It may be a good option for individuals that haven’t ruled fertility options out. However, more research is likely required. 

What are the side effects of treatments? 

  • With gels (the transdermal treatments), side effects include potential rash and potential transference of the testosterone through the clothes or touch to family members or children; therefore, individuals have to be very careful with washing their hands after treatments.
  • With injections, patients can have discomfort or bruising. 
  • Overall, there can be mood changes if testosterone levels fluctuate wildly or are too high. High testosterone levels can lead to the production of red blood cells in the body, leading to something called Polycythemia, where there are too many red blood cells in the bloodstream, and the blood gets thicker and puts patients at risk of further complications. This needs to be monitored. 
  • Testosterone therapy typically will result in the suppression of sperm production. 
  • Some patients can experience acne or oily skin, or male pattern hair loss.

Are there alternative treatments?

Alternatives to medical therapy include lifestyle measures. The use of supplements is not recommended as they are not well controlled. The effectiveness is less predictable due to the lack of regulation of their active ingredients.

Are there over-the-counter low testosterone treatments?

None that are medical grade and have appropriate regulation over their production to give confidence in the type of response and potential side effects or damage they may cause. These are not recommended.


If you or someone you care about is suffering because of low testosterone, the best thing to do is connect with a professional in the medical community, such as your primary care physician and have a discussion about navigating your symptoms and checking and managing low testosterone appropriately. 

For couples, connect with a primary care doctor to ensure that low testosterone is being properly investigated and managed, to help overcome some of the symptoms, and to have an open dialogue so that each partner understands the symptoms present and what needs to be overcome.

Frequently asked Questions

This topic is difficult to study, and most of the literature has significant limitations. We know that to generate testosterone, it needs cholesterol, which is the precursor. Therefore, there has to be some degree of healthy sources of cholesterol intake, which often coincide with Omega-3s. But this likely does not boost testosterone; rather, it helps support normal, natural testosterone production, along with the previously mentioned strategies.

In essence, yes. There are different ways of measuring serum testosterone depending on the location in the body. Testosterone can be freely circulated in the blood, it can be bound to the sex hormone-binding globulin (SHBG) protein (which is not active or cannot access the cells), or it can be bound to the albumin protein (which is a looser binding and therefore can also be biologically active). 

Low testosterone is usually associated with a lower libido or sex drive, more so than erectile dysfunction. Just the finding of low testosterone does not make it impossible for men to have erections; a very little amount of testosterone is thought to be needed to obtain an erection.

That being said, testosterone levels may have somewhat of a modulatory effect on erections. Men with erectile dysfunction that are failing treatment and also have low testosterone could be trialled on testosterone therapy to see if their erectile function improves.

Yes. Even though testosterone is incredibly important for sperm production, low testosterone levels in the blood may be the tip of the iceberg. Testicular testosterone levels are typically around 100 times higher and could be within normal limits within the testicle and support the fullest sperm production. Low testosterone does not cause low sperm counts as a general rule of thumb. 

However, in some specific scenarios, enhancing testosterone through promoting the body’s production can sometimes be helpful; this area is quite controversial, and the literature is not conclusive. 

Taking testosterone therapy will shut down sperm production; it is never used when fertility is being considered.

There is conflicting data in the literature. Some studies would suggest that men with lifelong rapid ejaculation might have higher free testosterone levels. It’s not clear if there is an association between blood testosterone levels and premature or rapid ejaculation. Low testosterone has, however, been associated with delayed orgasm, delayed ejaculation, or inability to achieve orgasm. 

Low testosterone can make it difficult to maintain lean muscle mass and achieve weight loss. Low levels can be associated with increased fat or adipose tissue. 

Low testosterone has been associated with low mood or depressive-like symptoms, decreased energy and difficulties concentrating. 

There is minimal data that suggests vitamin D, zinc and magnesium supplementation may result in increased testosterone levels. However, these are very small studies, and the research needs to be performed to substantiate these results. At present, the evidence is not clear.

Further contributing to the diet and testosterone, there’s also evidence that high-fat diets or energy restrictions (as in low calorie or fasting diets) can reduce testosterone production.

The results in the literature are variable. Some studies have shown lower testosterone levels in individuals that use marijuana, some show no difference, and some show increased levels with recent use. The evidence is inconclusive.

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Medically reviewed by

Dr. Ryan Flannigan

Dr. Ryan Flannigan, MD, B.Sc.

Dr. Flannigan is director of the Male Reproductive and Sexual Medicine Research Program in the Department of Urologic Sciences, and fellowship director for Male Reproduction, Medicine and Microsurgery

More about Dr. Ryan Flannigan