For men, testosterone is a sex hormone that plays many important roles throughout various stages of life. It helps the body grow and develop masculine characteristics.
The pituitary gland, located at the base of the brain, sends signals to the testes to produce testosterone. This hormone is then released in the blood and carried throughout the body.
Testosterone affects many different parts of the body, including:
- Bone growth and strength
- Deepening of the voice during puberty
- Energy and mood
- Facial and pubic hair growth during puberty
- Muscle mass and strength
- Production of red blood cells
- Sex drive, or libido
- Sperm production
Signs and Symptoms of Low Testosterone
When your body doesn’t produce enough testosterone, many bodily functions are affected. In men, symptoms of low testosterone, also called testosterone deficiency, vary greatly and can include:
- Decreased muscle mass
- Depressed mood
- Difficulty concentrating
- Erectile dysfunction
- Hot flashes
- Increased body fat
- Increased breast size
- Insulin resistance
- Irritability
- Loss of bone strength and increased risk of fracture
- Loss of body and facial hair
- Trouble sleeping
- Low sex drive
- Low sperm count
Keep in mind that many of these symptoms can be signs of other conditions or a normal part of the aging process. But if you notice changes in your body that concern you, talk to your primary care provider.
What Causes Low Testosterone?
In many men, levels of testosterone drop naturally as they age. This happens gradually, about 1 to 2 percent per year, as the testes produce lower amounts of hormone.
But other problems can lead to more rapid testosterone loss that isn’t normal. Some causes include:
- Chronic illness or infection
- Genetic diseases such as Klinefelter syndrome and hemochromatosis
- Injury to the testicles
- Low thyroid function
- Obesity
- Problems with the hypothalamus or pituitary glands, including tumors, infections and autoimmune conditions
- Side effects of certain medications, such as hormones used to treat prostate cancer
- Use of prescription and anabolic steroids
- Narcotic use
- Side effects of certain treatments, such as chemotherapy and radiation
- Poor sleep
- Lack of regular aerobic exercise
- Stress
- Testicular cancer
Risks of Low Testosterone
Having testosterone deficiency can affect your health in many ways, including:
- Increased risk of atherosclerosis, and therefore risk of heart attack and stroke
- Increased mortality
- Insulin resistance and Type 2 diabetes
- Metabolic syndrome
- Obstructive sleep apnea
- Weight gain
- Increased risk of high-grade prostate cancer
- Erectile dysfunction
- Decreased libido
- Decreased energy
Diagnosing and Treating Low Testosterone
To determine whether your symptoms are the result of low testosterone, as well as the best way to treat it, your provider will:
- Perform a physical exam
- Review your health history to determine if another condition could be causing your symptoms
- Do blood tests to check your testosterone level. Because levels of this hormone can fluctuate, it may be necessary to do several tests.
If you are diagnosed with low testosterone, your provider will likely order additional tests before determining the best course of treatment. You may need a bone density test to determine if you have or are at risk for osteoporosis, as low testosterone can make bones brittle. In this case, your treatment may include medication for osteoporosis.
For some men, testosterone replacement therapy (TRT) can help resolve symptoms and help them feel better. Many older men, as well as young men with very low testosterone, can benefit from this treatment. However, TRT also comes with risks, and it’s not appropriate for everyone. The Endocrine Society recommends that only men who display several symptoms and show low levels of testosterone in blood tests go on TRT.
Your provider may recommend other lifestyle changes before prescribing TRT. For example, if you have gained weight, regular aerobic exercise (a minimum of 30 minutes 3 days a week during which your heart rate goes up) and getting good sleep (at least 8 hours a night) will increase your testosterone levels. If you are on a medication that affects testosterone, your provider might change your treatment plan.
Benefits and Risks of TRT for Low Testosterone
Keep in mind you may not be a candidate for TRT if you were diagnosed with prostate or breast cancer, have an elevated level of prostate-specific antigen in your blood, or have a prostate nodule that your doctor feels during an exam.
TRT comes with risks, which include:
- Temporary infertility
- Elevated hematocrit
- Blood clots (rare)
- Swelling of the ankles or hands (rare)
- Acne (rare)
Due to these risks, you should not take TRT if you have:
- A condition called thrombophilia, in which you are at higher risk for developing blood clots
- A desire to become a father in the near future
- Elevated red blood cell counts
- Symptoms of low urinary tract problems
- Untreated sleep apnea
But men who are able to take TRT often see results fairly quickly, within four to six weeks of beginning therapy. However, it’s important to note that some changes, like building muscles, can take up to six months.
TRT is available in many different forms, including:
- Gels: Topical gels should be spread on the upper arms, shoulders or thighs once per day.
- Injections: Different amounts of testosterone get injected into the patient every one to two weeks. These injections may cause levels to spike and then slowly drop off, creating a mood and energy boost before trailing off.
- Oral medication: You can swallow capsules or attach tablets to your inner cheek twice per day.
- Pellets: Your provider will implant these under the skin around the hips or buttocks. Pellets need to be replaced every three to six months.
- Skin patch: The patch, which you apply every 24 hours in the evening, releases small amounts of testosterone into the skin.
After starting TRT, be sure to see your provider regularly. He or she will keep a close eye on your testosterone levels and watch for any possible side effects.
More to Read
- Healthy Prostate Pointers
- How to Spot the Signs of Benign Prostatic Hyperplasia (Enlarged Prostate)
- Prostate Cancer: What Men Need to Know
- Signs of Testicular Cancer
Medically reviewed by Christopher Runz, DO.
