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Low Testosterone: Causes, Symptoms & Treatment

Kelly Brown MD, MBA

Reviewed by Kelly Brown MD, MBA

Written by Geoffrey C. Whittaker

Published 09/14/2017

Updated 04/18/2024

Testosterone is responsible for several key functions in the body, from the development of your voice, hair and genitals to maintaining sexual function and fertility. It also plays a role in mental health, helping manage everything from moods to your level of interest in sex. But low testosterone in men can be an issue.

What happens when a man’s testosterone is low? The unsurprising answer is that all of these things can be impacted — negatively. How serious the effects of low testosterone are depends on numerous factors like your age and health.

It can all be a bit tricky to understand, even for experts, but we’re here to help you get a firm grasp on what might be going on. We’ll explore the causes, symptoms and treatments for low testosterone, along with what to do if you think you’re seeing the signs of it in yourself.

Low testosterone in men (also called low T or male hypogonadism) is exactly what it sounds like: lower than normal levels of the male hormone testosterone.

Those levels are important. Testosterone is the primary male sex hormone, belonging to a class of hormones referred to as androgens.

In men, the testes convert cholesterol into testosterone, and the pituitary gland — a small gland at the base of your brain that produces other hormones — regulates testosterone production. See also: Can you get an erection without testes?

Although testosterone is present in both men and women, it’s produced in far higher amounts in men.

Most men have healthy, optimal testosterone levels when they’re young. It’s common and normal to experience a gradual decline in your body’s overall testosterone production once you reach your 40s, 50s, 60s or beyond. But it can occur at an abnormally fast pace for some men.

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Testosterone levels can vary significantly between individuals. In men, the standard range for testosterone is between 300 and 1,000 nanograms per deciliter (ng/dL) of blood or between 10 and 35 nanomoles per liter (nmol/L). 

It’s normal for testosterone levels to fluctuate throughout the day. Most men experience their highest testosterone levels in the morning, with the testes producing testosterone following your circadian rhythm.

As mentioned above, there’s no one-size-fits-all level at which men’s testosterone levels are thought of as “normal.” Instead, testosterone levels exist across a range, with any level between 300 and 1,000 nanograms per deciliter of blood considered healthy. 

The American Urological Association (AUA) defines low testosterone as any testosterone reading below this level, accompanied by symptoms, following two morning testosterone level tests taken on separate dates.

What causes low testosterone? Many factors can contribute to low testosterone production in men, from diet and lifestyle to age and illness.

Common risk factors and causes of low testosterone include:

  • Being overweight or obese. Obesity is linked to a reduction in total testosterone, as well as reduced levels of hormones, such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

  • Injury or infection of the testes. Injuries that affect the testes, such as physical trauma or complications due to poor blood supply, may result in low testosterone. Infections affecting the testicles, such as orchitis, may also affect testosterone production.

  • Diabetes. Research shows that men with type 2 diabetes are more likely to develop low testosterone.

  • Metabolic disorders. Certain metabolic disorders, such as hemochromatosis (extra iron buildup in the body), can cause or contribute to testosterone deficiency.

  • Alcohol abuse. Drinking heavily (and frequently) can have negative effects on sexual health, including reduced production of testosterone and other reproductive hormones.

  • Internal organ damage. Severe damage to your liver (liver disease or cirrhosis) and kidneys (renal failure) can affect your body’s production of testosterone.

  • Obstructive sleep apnea. Sleep has a large effect on testosterone production. Because of its impact on sleep duration and quality, obstructive sleep apnea may result in reduced testosterone production and an increased risk of low T.

  • Other health conditions. Other medical conditions — including HIV/AIDS, inflammatory conditions like sarcoidosis and chromosomal conditions like Klinefelter syndrome — can contribute to low testosterone levels in men.

  • Anabolic steroid abuse. Anabolic steroids used to increase muscle mass and strength can disrupt natural testicular function, potentially causing testicular atrophy (decreased testicular size) and reduced testosterone levels.

  • Aging. As you get older, your hormone levels naturally change. For women, production of the primary female hormone estrogen drops in menopause, causing a range of physical changes. For men — although the decline isn’t quite so sudden or significant — it’s common for testosterone levels to gradually decrease over time. This means your risk of dropping to a less-than-normal testosterone level will increase as you get older. Research published in the journal Frontiers in Endocrinology notes that approximately 40 percent of men over 45 have clinically low testosterone levels.

The male body produces testosterone at a rate specific to each individual. But what can happen when your body doesn’t make enough?

A decrease in testosterone production can lead to problems with sex drive, sperm count, muscle mass levels, fat distribution, bone density and even red blood cell production.

If you have low testosterone, you may notice one or more symptoms. They can vary in severity from mild issues to serious ones that contribute to medical conditions or affect your quality of life as a man.

We’ll go over several of the most common signs of low testosterone in men below, along with information on how each issue may affect your health and well-being.

Reduced Sex Drive (Libido)

One of the most common signs of low testosterone is a low sex drive (aka low libido). You may have less interest in sexual activity or realize you’re not spending as much time thinking about sex as you used to.

Many men notice a decline in sexual desire with age, but low testosterone can produce a more drastic reduction, particularly in younger men.

Erectile Dysfunction (ED)

The relationship between testosterone levels and erections isn’t totally clear. But evidence suggests low testosterone levels can affect sexual function and contribute to common male sexual performance issues such as erectile dysfunction (ED).

Testosterone can trigger the release of nitric oxide, an essential molecule for developing and maintaining an erection. This means that when your testosterone levels are low, it might become more difficult to get and keep an erection.

It could also mean spontaneous erections (like waking up with morning wood) don’t happen anymore — or at least not as frequently as they normally would.

Since erectile dysfunction can occur for numerous reasons, you shouldn’t rush to assume you have low testosterone if you’re having erection troubles.

However, combined with other symptoms listed above and below, erectile dysfunction could be a sign of a testosterone-related issue.

Decreased Semen Volume and Low Sperm Count

Androgens like testosterone and dihydrotestosterone (DHT) play a major role in stimulating your prostate and seminal vesicles, which are responsible for producing semen.

Low testosterone may also affect your body’s ability to produce sperm, potentially resulting in a reduced sperm count. In some cases, low testosterone can even lead to infertility.

Decreased Testicle Size

In addition to producing a lower amount of sperm, your testicles may become physically smaller as testosterone levels decline. 

One study published in the journal Andrologia found an association between lower-than-normal levels of testosterone and reduced testicular volume.

However, this doesn’t necessarily mean your testicles will shrink by any significant amount if you’re affected by low T.

Sleep Disturbances

Low testosterone may cause sleep disturbances and disorders such as insomnia. If you have lower-than-normal levels of testosterone, you might find it hard to fall asleep or stay asleep throughout the night.

Low Energy and Fatigue

Since low T can affect sleep quality, you may feel tired and less motivated to engage in certain activities throughout the day.

Some men with low testosterone report feeling fatigued, even after getting a healthy amount of sleep. Others report reduced physical endurance, which might make some tasks more physically taxing and difficult to perform.

Hot Flashes

Low testosterone levels could increase your risk of experiencing hot flashes — sudden feelings of warmth across your face and chest. These may be accompanied by sweating, flushing and other symptoms.

Loss of Muscle Mass

As an anabolic (metabolism-related) hormone, testosterone plays a vital role in building and maintaining muscle mass. If you have low testosterone levels, you could experience a decrease in muscle mass and physical strength.

This could mean certain exercises, such as weightlifting and calisthenics, are more challenging to perform than in the past.

It’s important to keep in mind, however, that changes in muscle mass don’t always cause changes in strength or muscle function.

Increased Body Fat

Besides losing muscle mass, you may find your body composition changing and your body fat percentage increasing.

Research shows that obesity reduces testosterone and that waist size is a strong predictor of low testosterone. This may further compound the problem, with low testosterone contributing to an increase in body fat levels and increased fat affecting testosterone production.

Increased fat from low testosterone levels may have other negative effects on your health. For example, low T is also associated with high lipid levels, high blood pressure and other issues that may increase your risk of cardiovascular disease.

Loss of Bone Mass

Testosterone is an essential hormone for bone growth and maintenance. If you have low levels of testosterone, you may be more likely to suffer from bone mass loss. This could increase your risk of developing fractures.

Over time, the effects of low testosterone in males can result in skeletal diseases such as osteoporosis.

Mood Changes

Not only does testosterone affect many physiological processes, but it can also have an impact on cognitive function, performance and mood. 

If you have low testosterone, you might have a higher risk of developing mood disorders like depression. Low testosterone can also lead to difficulty concentrating and a tough time finding words to use in conversation.

Memory Trouble

Beyond affecting your ability to concentrate or verbalize your thoughts, low testosterone is often linked to memory issues. Some men with low testosterone report experiencing “brain fog” and poor memory.

Combined with the other cognitive symptoms listed above, this may hurt your workplace or academic performance.

Despite all this, research hasn’t found a clear link between testosterone supplementation and an improvement in memory in men with low testosterone.

Reduced Red Blood Cell Count (Anemia)

Testosterone is critical to the creation of red blood cells, which are essential for delivering oxygen to organs and removing carbon dioxide from the body.

Research shows that older men and women with low testosterone have lower red blood cell counts and an increased risk of developing anemia.

Body Hair Loss

Testosterone and other androgens are key to the development and growth of facial and body hair. If you’re deficient in testosterone, your body hair may not grow to the same length or thickness as it previously did.

Some parts of your body that typically have hair, such as your armpits or genitals, may start to thin. In addition to affecting body hair growth, low testosterone may also reduce the growth of your facial hair.

Gynecomastia (Male Breast Development)

Low testosterone levels can sometimes result in gynecomastia — a form of breast growth that affects men.

Gynecomastia can cause your nipples to become swollen or tender. You might feel a growth in the glandular tissue behind one or both of your nipples. In some cases, this breast tissue growth may feel firm and rubbery.

Research suggests that gynecomastia may occur due to an imbalance between estrogen and androgen hormones.

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If you think you might have low testosterone, it’s best to bring this up with your healthcare provider or schedule an appointment with a urologist.

At your appointment, your provider will ask about your medical history and your family health history, then perform a physical exam.

They’ll be able to check your testosterone levels, as well as your levels of luteinizing hormone (LH), prolactin, hemoglobin and other related hormones, with a simple blood test.

If your total testosterone level is below 300 ng/dL, and you have signs or symptoms above, you may get a low testosterone diagnosis.

If you’re diagnosed with low T, your healthcare provider will suggest treatment options. This may include testosterone replacement therapy, lifestyle changes or medications to manage the symptoms of low testosterone.

Testosterone Replacement Therapy (TRT)

Testosterone replacement therapy (TRT), or testosterone therapy, is a form of hormone replacement therapy for men. 

This treatment uses artificial testosterone to increase circulating testosterone levels and treat the symptoms of low T. The supplemental testosterone comes in several forms, including skin patches, topical gels, tablets, implants and injectable testosterone. 

Testosterone replacement therapy has real benefits. But it can also cause side effects like skin irritation (particularly with gels and liquids) and more serious issues, such as an increased risk of blood clots and heart health problems, or infertility.

In some cases, testosterone replacement therapy can also contribute to cosmetic issues such as gynecomastia, a form of male breast growth. Testosterone replacement therapy can also result in testicular shrinkage.

Additionally, TRT may be unsafe if you have a history of prostate cancer, breast cancer or other forms of cancer affected by androgen levels. If you’ve previously received cancer treatment, it’s important to inform your healthcare provider before considering testosterone treatment.

Find out more about the benefits, risks and potential side effects of TRT in our complete guide to testosterone replacement therapy

Medication to Increase Testosterone Production

An alternative to testosterone replacement, or sometimes used alongside testosterone, are medications that increase production of testosterone from the testicles.  

These treatments can include clomiphene citrate (Clomid), anastrozole (Arimidex), or human chorionic gonadotropin (hCG), which affect various signaling pathways directing the testicles to make more testosterone.  

Because of the mechanisms of action, these medications avoid the negative impacts TRT can have on sperm and can actually improve fertility in some men.

Lifestyle Changes for Low Testosterone in Men

If you’re concerned about your testosterone levels but medication isn’t quite right for you, other options are available. 

Though changing your habits might not be enough to treat clinically low testosterone, making some lifestyle adjustments could help increase your testosterone production naturally.

In addition to medicinal treatment options, a healthcare professional might suggest trying:

  • Exercising more often

  • Finding healthy ways to minimize stress

  • Adjusting your diet to improve nutrition and reduce foods associated with hormonal changes

  • Getting a full night’s sleep regularly

  • Making an effort to shed excess body fat

Our guide to increasing your testosterone levels goes into more detail about how you can adjust your habits and lifestyle for better testosterone production.

Medication for Erectile Dysfunction

Although it’s generally uncommon for low testosterone to cause severe or persistent ED, some men with low T may find it harder to get or maintain an erection.

If you have erectile dysfunction and low testosterone, your healthcare provider might prescribe an ED medication such as sildenafil (generic Viagra®) to make it easier to get and maintain an erection.

Other medications for erectile dysfunction include tadalafil (generic Cialis®) and avanafil (Stendra®), a newer oral medication for ED that has a lower risk of side effects.

Our guide to the most common ED treatments goes into more detail about how ED medications work and their potential side effects. 

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Low testosterone is a common problem for men. It can affect everything from sex drive and mood to energy levels and cognitive function. And although it’s natural to experience some decline in testosterone production over time, it might be a health concern if it happens too quickly.

Thankfully, numerous treatments are available that can help you maintain healthy testosterone levels if you develop low T in your 30s, 40s, 50s or beyond.

Consider the potential signs of low testosterone and make notes of any that sound familiar before you talk to your healthcare provider. They’ll be able to check your testosterone levels and, if appropriate, provide a treatment plan or refer you to a urologist.

If you don’t notice any other signs of low T but find it difficult to get or maintain an erection, you can access treatment for ED by taking part in an online erectile dysfunction consultation with a healthcare provider.

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Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Kelly Brown MD, MBA
Kelly Brown MD, MBA

Dr. Kelly Brown is a board certified Urologist and fellowship trained in Andrology. She is an accomplished men’s health expert with a robust background in healthcare innovation, clinical medicine, and academic research. Dr. Brown is a founding member of Posterity Health where she is Medical Director and leads strategy and design of their Digital Health Platform, an innovative education and telehealth model for delivering expert male fertility care.

She completed her undergraduate studies at University of North Carolina at Chapel Hill (go Heels!) with a Bachelor of Science in Radiologic Science and a Minor in Chemistry. She took a position at University of California Los Angeles as a radiologic technologist in the department of Interventional Cardiology, further solidifying her passion for medicine. She also pursued the unique opportunity to lead departmental design and operational development at the Ronald Reagan UCLA Medical Center, sparking her passion for the business of healthcare.

Dr. Brown then went on to obtain her doctorate in medicine from the prestigious Northwestern University - Feinberg School of Medicine and Masters in Business Administration from Northwestern University - Kellogg School of Management, with a concentration in Healthcare Management. During her surgical residency in Urology at University of California San Francisco, she utilized her research year to focus on innovations in telemedicine and then served as chief resident with significant contributions to clinical quality improvement. Dr. Brown then completed her Andrology Fellowship at Medical College of Wisconsin, furthering her expertise in male fertility, microsurgery, and sexual function.

Her dedication to caring for patients with compassion, understanding, as well as a unique ability to make guys instantly comfortable discussing anything from sex to sperm makes her a renowned clinician. In addition, her passion for innovation in healthcare combined with her business acumen makes her a formidable leader in the field of men’s health.

Dr. Brown is an avid adventurer; summiting Mount Kilimanjaro in Tanzania (twice!) and hiking the incredible Torres del Paine Trek in Patagonia, Chile. She deeply appreciates new challenges and diverse cultures on her travels. She lives in Denver with her husband, two children, and beloved Bernese Mountain Dog. You can find Dr. Brown on LinkedIn for more information.

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