Medically reviewed by our clinical team · Last reviewed Oct 19, 2026 · How we create and review content
What counts as low testosterone?
Testosterone deficiency (hypogonadism) means two things are both true: you have symptoms consistent with low testosterone, and blood tests confirm it's low on more than one morning test. The American Urological Association uses a total testosterone below 300 ng/dL as a reasonable cutoff. Testosterone tends to decline gradually with age, but age alone isn't a diagnosis.
Common symptoms of low testosterone
Sexual symptoms
- Lower sex drive (libido)
- Fewer spontaneous or morning erections
- Erectile difficulties (often with other causes too)
- Fertility problems
Physical symptoms
- Fatigue and lower energy
- Less muscle mass and strength
- More body fat, especially around the abdomen
- Reduced bone density
- Breast tenderness or enlargement, and less body hair
- Hot flashes, in more severe cases
Mood and cognitive symptoms
- Low mood or irritability
- Less motivation or self-confidence
- Trouble concentrating or remembering
The Mayo Clinic describes these same categories and notes that many can also be caused by other conditions.
Conditions that mimic low T
- Obstructive sleep apnea: causes daytime fatigue and can lower testosterone. See the NHLBI overview.
- Thyroid disease: an underactive thyroid causes fatigue, weight gain and low mood. It's checked with a TSH test.
- Type 2 diabetes and obesity: both are linked with lower testosterone.
- Depression: overlaps with low drive, poor focus and fatigue.
- Anemia and B12 deficiency: cause tiredness and weakness. See vitamin injections.
- Medications: opioids, steroids and some others can lower testosterone or cause similar symptoms.
- Alcohol, poor sleep and overtraining: common and fixable.
Who should get tested?
Consider testing if you have several of the symptoms above, especially the sexual ones, and they've lasted for weeks to months. Also consider it if you have a condition linked to low testosterone, such as type 2 diabetes, obesity, a history of testicular injury, pituitary disease or long-term opioid use. Testing is straightforward. Our testosterone blood test guide explains what to expect.
What happens if your testosterone is low
A low result is the start of the conversation. Your clinician will repeat the test, may check LH and FSH to find where the problem starts, and will look for reversible causes. If hypogonadism is confirmed and treatment is appropriate, testosterone replacement therapy is an option, with risks discussed and monitoring planned.
Getting tested in Houston
TRT Houston arranges testing for men across Greater Houston. You complete an online intake, have blood drawn in the morning at a nearby Quest or Labcorp location, and review the results by video with a Texas-licensed clinician. Start online or call (281) 670-9727.
Frequently asked questions
At what age does testosterone start to drop?
Levels generally peak in early adulthood and decline gradually afterward. The Mayo Clinic notes a typical decline of about 1% a year after age 30 or 40. Many men stay in the normal range throughout life.
Can young men have low testosterone?
Yes. Hypogonadism can occur at any age due to genetic, testicular, pituitary or medication-related causes.
Can I check testosterone with a home test?
Some home tests exist, but diagnosis needs properly timed, repeated measurements, ideally from an accredited lab, and clinical review.
Do testosterone boosters work?
Most over-the-counter 'boosters' lack good evidence and aren't regulated as drugs. Treating causes like sleep apnea, excess weight or medication effects is more effective.
Sources and further reading
- American Urological Association: Evaluation and Management of Testosterone Deficiency guideline
- Mayo Clinic: Testosterone therapy, potential benefits and risks as you age
- Endocrine Society: Testosterone Therapy in Men With Hypogonadism (clinical practice guideline, 2018)
- NIH NHLBI: Sleep apnea
- MedlinePlus (NIH): TSH (thyroid-stimulating hormone) test