Low Testosterone: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Low Testosterone?
A primary care doctor can start the evaluation of low testosterone. An endocrinologist (a hormone doctor) or a urologist (a doctor who treats the male reproductive system) often helps manage it. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is low testosterone?
Low testosterone in men is also called male hypogonadism. It happens when the testicles cannot make enough male hormones, such as testosterone. Low testosterone is also called low T. Here we cover men. In females, low levels are normal. Extremely low levels may signal an adrenal gland, pituitary gland, or ovary disorder.
Testosterone helps control sex drive and helps with muscle and bone growth. In males, it is also involved in body hair growth, a deepening voice during puberty, sperm production, making new red blood cells, and growing taller.
Symptoms
Symptoms depend on whether low testosterone starts before or after puberty. They may include:
- Low sex drive.
- Erectile dysfunction, which is trouble getting or keeping an erection.
- Infertility, which is trouble getting someone pregnant.
- Enlarged breasts.
- Loss of muscle mass.
- Loss of armpit and pubic hair, or lack of face and body hair.
- Thinning bones, or anemia with no known cause.
Before puberty, low testosterone can cause less height increase than expected. It can also slow the development of male traits such as hair growth, voice changes, and growth of the scrotum and penis. Men may also notice they do not need to shave as often.
Causes and who gets it
Causes of low testosterone include:
- Some medicines, such as chemotherapy and opioid pain medicines.
- Diseases of the testicles, such as mumps and testicular cancer.
- Injury to the testicles.
- Obesity.
- Genetic diseases, such as Klinefelter syndrome.
- Other diseases, such as cystic fibrosis or long-lasting liver or kidney disease.
- A pituitary gland disorder.
Constant, low-level injury to the scrotum can raise your risk. Riding a motorcycle or bicycle is an example. Frequent or heavy marijuana use and undescended testicles at birth also raise the risk. Testosterone also normally drops slowly with age.
How doctors diagnose it
Your doctor will do a physical exam. It may show small, firm testicles. Blood tests may show a low level of testosterone. Tests of other hormones help show if the cause is in the testicles or in the pituitary gland.
The most common test is a total testosterone test. One test result alone cannot diagnose a condition. Your doctor also looks at your symptoms. Blood is usually drawn in the morning, between 7 and 10, when testosterone is typically highest. If fertility is a concern, you may also have a semen analysis, which counts healthy sperm.
Treatment
Testosterone replacement therapy (TRT) can treat some forms of it. It can be given as a gel, patch, injection, or implant. TRT can help reverse symptoms, although it may not restore fertility. Many forms of low testosterone cannot be reversed.
FDA says testosterone is approved only for men with low testosterone and a related medical condition. If a medicine or activity is causing the problem, avoiding it may bring testicle function back to normal.
TRT has risks, so your doctor will watch you closely. It may cause an enlarged prostate that makes it hard to urinate, blood clots, changes in sleep and mood, and changes in good cholesterol. It can make your blood too thick, a problem called polycythemia. FDA also says all testosterone products can raise blood pressure.
When to see a doctor
Contact your provider if you have symptoms of low testosterone. Also contact your provider if you are on TRT and you think you are having side effects from the treatment.
Blood clots are a possible side effect of TRT. If you are on TRT, call 911 or go to the emergency room for chest pain, trouble breathing, or sudden weakness or change in vision.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Such a doctor can review your symptoms and medicines, order blood tests, and follow your testosterone level over time. They can also refer you to a hormone doctor or a urologist when needed.
Common questions
Does low testosterone happen with aging?
Yes, testosterone normally drops slowly with age. This can make low testosterone hard to diagnose in older men.
When is the best time of day to check testosterone?
The morning is best. A blood sample is usually taken between 7 and 10 in the morning, when testosterone levels are typically highest.
Can testosterone treatment restore fertility?
Not always. TRT can help reverse symptoms, although it may not restore fertility. Men who are having chemotherapy that can cause low testosterone should talk about freezing sperm first.
What are the risks of testosterone replacement therapy?
Risks include an enlarged prostate, blood clots, changes in sleep and mood, and blood that becomes too thick. Your provider needs to watch you closely. FDA also says all testosterone products can raise blood pressure.
Can low testosterone be prevented?
Some causes can be avoided. Avoid risky activities, if you can, and stay active. Try to prevent weight gain as you get older.
Sources
- MedlinePlus - Male hypogonadism
- MedlinePlus - Testosterone Levels Test
- U.S. Food and Drug Administration - FDA issues class-wide labeling changes for testosterone products
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
