Low Testosterone in Men: Symptoms, Causes and Testing
Low testosterone in men, called hypogonadism, means the body makes too little of its main male hormone. Common signs include low sex drive, fewer morning erections, less body hair and enlarged breasts. Because symptoms overlap with many other problems, it is confirmed only with repeat early-morning blood tests. Leticia Vargas, MD, checks men for low testosterone in San Antonio.
Key facts
- Symptoms alone are not enough. Diagnosis needs both symptoms and blood tests that are clearly and consistently low.
- Test twice, in the morning. Testosterone is highest in the morning and changes day to day, so labels and guidelines call for at least two early-morning tests on different days.
- A first low result often changes. The Endocrine Society notes that about 30% of men with a low first result have a normal level when tested again.
- The AUA's cutoff: the American Urological Association uses a total testosterone below 300 ng/dL as a reasonable cutoff to support the diagnosis, along with symptoms.
- Finding the cause matters. Some causes, like certain medicines, can be changed without starting testosterone.
What are the symptoms of low testosterone in men?
According to MedlinePlus (NIH) and medical guidelines, signs may include:
- low sex drive (libido);
- fewer spontaneous or morning erections;
- loss of armpit and pubic hair, or shaving less often;
- enlarged or tender breasts;
- smaller testicles;
- infertility or a low sperm count;
- loss of muscle mass;
- weak bones or a fracture from a minor fall;
- tiredness or low mood that has no other cause.
Many of these, especially tiredness, low mood and weight gain, are also caused by poor sleep, depression, thyroid problems, diabetes, heavy drinking or stress. That is why a blood test, not a quiz, makes the diagnosis.
What causes low testosterone?
MedlinePlus lists several causes:
- medicines: steroid medicines (glucocorticoids), opioid pain medicines, ketoconazole and chemotherapy;
- testicle problems: injury, mumps, infection, a twisted testicle, testicular cancer, a varicocele, or iron overload (hemochromatosis);
- pituitary or brain problems that affect hormone signals;
- obesity;
- genetic conditions, such as Klinefelter syndrome;
- other risks: frequent or heavy marijuana use, and testicles that did not descend at birth.
Testosterone also falls slowly with age. That makes the diagnosis harder in older men, and guidelines advise against treating every older man for a low number alone.
How is low testosterone tested?
Step 1: morning blood tests. Total testosterone is measured early in the morning on at least two different days, ideally at the same lab. Fasting may be advised.
Step 2: tests to find the cause. If levels are low, your clinician may check:
- LH and FSH, the pituitary signals that tell the testicles to make testosterone;
- prolactin, a pituitary hormone that can lower testosterone when high;
- a blood count (hemoglobin and hematocrit) before any treatment;
- PSA, a prostate blood test, for men over 40 before treatment;
- in some cases, iron studies, a semen test, or imaging.
Step 3: a talk about results. Results are read with your symptoms. A man with a borderline number and no symptoms usually does not need treatment.
Why does weight affect testosterone tests?
Extra weight can lower a protein in the blood called SHBG, which carries testosterone. When SHBG is low, total testosterone can look low even when the active part is normal. MedlinePlus notes this makes diagnosis harder in men with obesity, so extra testing may be needed. If weight is a concern for you, ask about our medical weight loss program.
What are my options if my testosterone is low?
Options depend on the cause and your goals:
- treat the cause, such as changing a medicine or treating a pituitary problem;
- lifestyle steps, such as weight loss, better sleep and less alcohol;
- testosterone therapy, for men with confirmed hypogonadism who are not trying to have a child soon. See testosterone therapy;
- fertility-sparing medicines, which a specialist may use for men who want children, since testosterone can lower sperm count.
What to ask your clinician
- Were both of my morning tests low?
- What is my LH and FSH, and what does that say about the cause?
- Could any of my medicines be lowering my testosterone?
- Do I need other tests, like prolactin or a semen test?
- If I want children, what are my options?
- What would happen if I don't treat it?
Frequently asked questions
What is a normal testosterone level for men? Lab ranges vary. The AUA uses total testosterone below 300 ng/dL, on at least two morning tests, as a reasonable cutoff to support a diagnosis when symptoms are present.
Can I test my testosterone at home? Home kits may give a single number, but a diagnosis needs repeat early-morning tests, ideally at the same lab, plus a medical review.
Should every man over 50 get his testosterone checked? No. The Endocrine Society advises against routine screening. Testing makes sense when you have symptoms or a condition linked to low testosterone.
Does low testosterone cause erectile dysfunction? It can play a part, but most erection problems have other causes, such as blood vessel disease or diabetes. Both are worth checking.
What is TRT? TRT stands for testosterone replacement therapy. Read our guide What is TRT?.
Book a visit
Call (210) 903-1030 or Book a visit. In-clinic in San Antonio
About the clinician
Leticia Vargas, MD, OB/GYN, founder of Yaso Wellness Health Clinic. About Dr. Vargas
Sources
Education only, not medical advice or a diagnosis. In an emergency, call 911.
