Low Testosterone

Testosterone is a hormone produced by the testes (in those assigned male at birth), and the ovaries (in those assigned female at birth). It is the primary sex hormone associated with males.

Testosterone stimulates the development of sex characteristics associated with males (like body hair and muscle growth) and is essential in the production of sperm.

Low levels of testosterone can cause a loss of sexual drive, reduced bone and muscle mass, mood disorders, and may exacerbate symptoms of erectile dysfunction. In this article, you will learn more about the symptoms of low testosterone, how low testosterone is diagnosed, and the treatments available.

Young man unhappy and disappointed in a white room

Sornranison Prakittrakoon / Getty Images

What Is Low Testosterone?

Some males have low testosterone levels. This is referred to as hypogonadism, testosterone deficiency syndrome (TD), low testosterone (Low-T), or andropause.

The American Urology Association (AUA) defines hypogonadism as total testosterone level of less than 300 nanograms per deciliter (ng/dL). The diagnosis is only made after two testosterone lab checks are done and the patient has symptoms.

Females may also have low testosterone, especially as they age. However, there are no conclusive guidelines on what should be considered “low” testosterone levels in females.

Aging and Testosterone

Testosterone levels naturally decline with age. In males, production of this hormone starts to fall after age 30 and continues to decline (about 1% per year) throughout their life.

Low testosterone affects almost 40% of males aged 45 and older. While low testosterone is more common in older males, it can occur in younger males as well. 

Causes of Low Testosterone

Some other causes of low testosterone levels in males include:

  • Obesity: Obesity may have an even bigger impact on testosterone levels than age. Research has found that increases in weight are directly related to lowering testosterone levels.
  • Congenital or chromosomal disease: This includes genetic conditions like Klinefelter syndrome (XXY) or Kallmann syndrome.
  • Being underweight: Abnormally low BMI levels, malnutrition, and excessive exercise can lead to low testosterone levels.
  • Pituitary disorders: This includes problems with how the pituitary functions. It may be the result of a pituitary tumor or brain tumor.
  • Undescended testicles: This usually resolves during early childhood. If not, though, it must be corrected. Otherwise, it can cause hormonal problems later in life.
  • Abnormally high levels of iron: This is also known as hemochromatosis.
  • Testicular injury: If just one testicular is injured, testosterone production may be normal.
  • Cancer treatment: Chemotherapy and radiation therapy can temporarily cause low testosterone.
  • HIV/AIDS: The virus can interfere with how the testes, pituitary, and hypothalamus function. This, in turn, can lead to low testosterone levels.
  • Major illness or surgery: This will usually reverse itself after some recovery time.
  • Medical or recreational drug use: For example, marijuana can cause lower testosterone levels.
  • Extremely high levels of stress: High levels of the stress hormone cortisol have been associated with lower levels of testosterone.
  • Sexually transmitted infections or other infections of the body: Medical stressors can affect T levels. In most cases, T levels can go back to your normal range after a few weeks or months of the illness.

Symptoms of Low Testosterone

A range of symptoms can occur if testosterone production drastically drops below normal. Signs of low testosterone are often subtle. Some symptoms that may indicate low testosterone levels may include:

Low Sex Drive

Testosterone plays a key role in libido (sex drive) in males. Someone with low T may experience a more drastic drop in their desire to have sex.

Difficulty With Erection

Erection problems in general are thought to be more of a byproduct of issues with blood vessels and nerves. Testosterone deficiency alone is generally not the cause of primary erectile dysfunction. However, low T levels and what it does to your sex drive can affect your ability to have or sustain an erection.

Low Semen Volume

Testosterone plays a role in the production of semen. People with low testosterone may notice a decrease in the volume of their semen during ejaculation.

Body Hair Loss

While there is a genetic component to balding, males with low testosterone may experience a loss of body and facial hair, too.


Males with low T often report extreme fatigue and decrease in energy levels.

Loss of Muscle Mass

Males with low T might notice a decrease in muscle mass. Studies have shown testosterone affects muscle mass, but not necessarily strength or function.

Increased Body Fat

Males with low T sometimes develop gynecomastia or enlarged breast tissue. This effect is believed to occur due to an imbalance between testosterone and estrogen.

Decreased Bone Mass

Testosterone helps produce and strengthen bones. So males with low testosterone, especially those who are older, have lower bone volume and are more susceptible to bone fractures.

Mood Changes

As well as the physical effects of low T, research suggests that men with low testosterone are thought to be more likely to face depression, irritability, or a lack of focus.

Affected Memory

Both testosterone levels and cognitive functions—such as memory—decline with age. As a result, doctors have speculated that lower testosterone levels could contribute to affected memory.

Low Blood Counts

Studies have found that adults with low T levels also had lower hemoglobin levels and were at an increased risk for having or developing anemia. Researchers have suggested that low testosterone may make you more susceptible to anemia.

Low Testosterone in Women

Testosterone is often thought of as a “male” hormone. However, those assigned female at birth also have testosterone in their bodies. Research shows that normal testosterone levels in females are vital to maintaining libido, cognitive function, lean muscle repair and growth, and bone strength. It may also play a role in reducing the risk of certain endocrine cancers.

It's possible that as with males, female testosterone levels naturally decline with age, and may lead to symptoms, such as low energy and impaired muscle growth. But at this time, research into the effect of low testosterone in females is limited and there are no conclusive guidelines for what should be considered “low” testosterone levels in females.

Are There Tests to Diagnose Low Testosterone?

Low testosterone is diagnosed by measuring testosterone levels with a blood test. Testing first thing in the morning is recommended as this is when males generally have the highest level of T circulating in their bodies.

A diagnosis of hypogonadism or low T requires two blood tests done on separate days. Your healthcare provider may order other lab tests to look at other sometimes reversible causes of your low testosterone levels.

Free Testosterone Levels

There are two kinds of testosterone found in your blood:

  • Free testosterone (also known as free T) is testosterone that is not chemically bound to anything else. 
  • Bound testosterone makes up the majority of your total testosterone levels. Around 98% of the testosterone in your blood is bound to one of two proteins: albumin or sex hormone-binding globulin (SHBG). 

When you have your testosterone levels tested, a healthcare provider will look at both your free testosterone levels and your total testosterone levels. Your total testosterone levels include both free and bound testosterone.

When to See a Healthcare Provider

If you have symptoms such as reduced sex drive or erection problems, you should see your healthcare provider. They can do a blood test to help determine whether you have low testosterone. Low T is also a known risk factor for cardiovascular disease so its important to get checked to not only help your symptoms but protect your heart.

How to Treat Low Testosterone Symptoms

If your low testosterone levels are the result of an underlying medical condition or lifestyle factor, then at least part of your treatment plan will be treating the original condition.

It may be possible in these cases to have testosterone levels return to normal levels after treatment or lifestyle change. This is not always an option, unfortunately. In these cases, your healthcare provider may recommend treatment such as testosterone replacement therapy (TRT).

Testosterone Replacement Therapy (TRT)

According to the American Urological Society, testosterone replacement therapy (TRT) may result in improvements in low sex drive, anemia, bone mineral density, lean body mass, and/or depressive symptoms. The evidence is inconclusive whether TRT improves cognitive function, measures of diabetes, energy, fatigue, lipid profiles, and quality of life measures.

There are several ways to do TRT. Discuss what option best suits your lifestyle and medical needs with your healthcare provider. TRT options include:

  • Short-acting intramuscular injections (into a muscle): This may include self-injections twice a week at low doses, or self-injections every 1 or 2 weeks at a higher dose.
  • Long-acting intramuscular injections: These are injections done through your healthcare provider, with effects lasting up to 10 weeks.
  • Testosterone gels: These are self-applied every day to the skin around the shoulders, biceps, or thighs. The amount you apply can be gradually increased to get higher levels.
  • Testosterone pellets: These are implanted into the fat in your buttocks every two to three months by your healthcare provider.
  • Testosterone patches: A bandage-like patch is placed daily by the patient. However, these have fallen out of favor due to skin irritation and more effective alternatives.
  • Oral testosterone: This is a pill taken twice daily to boost T levels.
  • Nasal testosterone gel: A small amount of viscous gel is placed into your nose daily.
  • Off-label oral medications. These are reserved for males who are trying to preserve fertility and sperm counts but need a safe boost of T levels.

Risks: Who Should Not Take Testosterone?

Testosterone replacement therapy may cause the prostate to grow. Therefore, if a person has early prostate cancer, there is concern that testosterone may stimulate the cancer's growth.

People who have prostate cancer are advised not take testosterone replacement therapy. It is important for all males considering testosterone replacement therapy to speak to their healthcare providers and undergo prostate screening before starting this therapy.


Low testosterone is a common side effect of the aging process in males. Most cases of low testosterone are treatable, and being aware of the symptoms can help a person to receive an early diagnosis and treatment.

A Word From Verywell

If you are experiencing symptoms of low testosterone such as low sex drive, erectile dysfunction, hair loss, and fatigue, speak to your healthcare provider. Most causes of low testosterone are easily treated.

Frequently Asked Questions

  • What happens when a man's testosterone is low?

    Testosterone is an important hormone in people assigned male at birth. It's thought to regulate sex drive (libido), bone mass, fat distribution, muscle mass and strength, and the production of red blood cells and sperm. When testosterone is low, it can have physical and mental effects.

  • How do I know if my testosterone levels are low?

    Symptoms of low testosterone in males may include:

    • Decreased beard and body hair growth
    • Decreased muscle mass
    • Depression
    • Difficulty with concentration
    • Enlarged or sensitive breasts
    • Erectile dysfunction
    • Fatigue
    • Hot flashes
    • Low sex drive
    • Reduced strength
  • What is the average testosterone level by age?

    Typical total testosterone levels in males, by age:

    7–10 years old - 1.80 to 5.68 ng/dl

    13–17 years old - 208.08 to 496.58 ng/dl

    19 years and older - 265 to 923 ng/dl

  • Does low T need to be treated?

    Most males with low-T will be treated if they have symptoms of low-T and blood tests showing low-T levels. Whether you seek treatment is your choice.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Urological Association. Evaluation and management of testosterone deficiency.

  2. Wierman ME, Arlt W, Basson R, Davis SR, Miller KK, Murad MH, Rosner W, Santoro N. Androgen therapy in women: a reappraisal: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2014 Oct;99(10):3489-510. doi:10.1210/jc.2014-2260

  3. Rivas AM, Mulkey Z, Lado-Abeal J, Yarbrough S. Diagnosing and managing low serum testosteroneProc (Bayl Univ Med Cent). 2014;27(4):321-324. doi:10.1080/08998280.2014.11929145

  4. Pantalone KM, Faiman C. Male hypogonadism: more than just a low testosteroneCleve Clin J Med. 2012;79(10):717-725. doi:10.3949/ccjm.79a.11174

  5. Kataoka T, Kimura K. Testosterone and Erectile Function: A Review of Evidence from Basic Research. IntechOpen; 2017. doi:10.5772/intechopen.72935

  6. Huo S, Scialli AR, McGarvey S, et al. Treatment of Men for "Low Testosterone": A Systematic ReviewPLoS One. 2016;11(9):e0162480. Published 2016 Sep 21. doi:10.1371/journal.pone.0162480

  7. Tsujimura A. The Relationship between Testosterone Deficiency and Men's HealthWorld J Mens Health. 2013;31(2):126-135. doi:10.5534/wjmh.2013.31.2.126

  8. Roy CN, Snyder PJ, Stephens-Shields AJ, et al. Association of Testosterone Levels With Anemia in Older Men: A Controlled Clinical TrialJAMA Intern Med. 2017;177(4):480–490. doi:10.1001/jamainternmed.2016.9540

  9. Davis SR, Wahlin-Jacobsen S. Testosterone in women--the clinical significanceLancet Diabetes Endocrinol. 2015;3(12):980-992. doi:10.1016/S2213-8587(15)00284-3

  10. MedlinePlus. Testosterone levels test.

  11. Osterberg EC, Bernie AM, Ramasamy R. Risks of testosterone replacement therapy in menIndian J Urol. 2014;30(1):2-7. doi:10.4103/0970-1591.124197

  12. Yao Q, Zhou G, Xu M, et al. Blood metal levels and serum testosterone concentrations in male and female children and adolescents: NHANES 2011-2012PLoS One. 2019;14(11):e0224892. Published 2019 Nov 7. doi:10.1371/journal.pone.0224892