Low Testosterone Symptoms in Men: Signs and When to Get Tested

What are the recognized symptoms of low testosterone?

The Endocrine Society clinical practice guideline on testosterone deficiency identifies a specific set of symptoms that, when present together, make low testosterone more likely 1Ref 1Bhasin S, Brito JP, Cunningham GR, et al. (2018).Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline.Recognized symptoms of hypogonadism including sexual and nonspecific symptoms; opioids as a cause of secondary hypogonadism; diagnosis requiring two confirmed morning samples; requirement for compatible symptoms alongside biochemical confirmation. These fall into two categories:

Sexual symptoms (more specific to testosterone deficiency) - Reduced libido (sexual desire) — often the most consistent symptom - Erectile dysfunction, particularly reduced spontaneous erections - Reduced genital sensation - Decreased ejaculatory volume

Nonspecific symptoms (can have many other causes) - Persistent fatigue and reduced energy - Depressed mood and increased irritability - Difficulty concentrating - Loss of lean muscle mass and strength - Increased body fat, particularly around the abdomen - Reduced bone density (diagnosed by DEXA scan) - Decreased body hair and, in some men, gynecomastia (breast tissue development)

The sexual symptoms — especially reduced libido — are more helpful diagnostically because they are relatively specific to testosterone's role. Fatigue and mood changes alone, without any sexual symptoms, are less likely to be primarily from low testosterone.

What conditions mimic low testosterone symptoms?

Many conditions produce a nearly identical symptom cluster to low testosterone:

• Depression: Fatigue, low motivation, mood changes, reduced libido, and difficulty concentrating are core features of depression — and depression itself can lower testosterone levels through effects on the hypothalamic-pituitary axis.
• Obstructive sleep apnea: Disrupts sleep, causes profound fatigue, and can lower testosterone through sleep fragmentation and oxygen desaturation.
• Hypothyroidism: Low thyroid function causes fatigue, weight gain, reduced libido, cognitive fog, and mood depression.
• Iron deficiency anemia: Produces significant fatigue and reduced energy.
• Chronic stress: Elevates cortisol, which directly suppresses testosterone production.
• Opioid use: Opioids strongly suppress the hypothalamic-pituitary-gonadal axis and are one of the most common drug-induced causes of secondary hypogonadism 1Ref 1Bhasin S, Brito JP, Cunningham GR, et al. (2018).Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline.Recognized symptoms of hypogonadism including sexual and nonspecific symptoms; opioids as a cause of secondary hypogonadism; diagnosis requiring two confirmed morning samples; requirement for compatible symptoms alongside biochemical confirmation.
• Excessive alcohol: Suppresses testosterone at multiple levels.

This overlap is why symptoms alone are not a diagnosis and lab testing is essential 1Ref 1Bhasin S, Brito JP, Cunningham GR, et al. (2018).Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline.Recognized symptoms of hypogonadism including sexual and nonspecific symptoms; opioids as a cause of secondary hypogonadism; diagnosis requiring two confirmed morning samples; requirement for compatible symptoms alongside biochemical confirmation.

Do these symptoms get worse gradually or suddenly?

In most men, the symptoms of testosterone deficiency develop gradually — over months to years. Longitudinal data from the Massachusetts Male Aging Study show that age-related testosterone decline averages about 1–2% per year, making symptoms easy to attribute to normal aging 3Ref 3Feldman HA, Longcope C, Derby CA, et al. (2002).Age Trends in the Level of Serum Testosterone and Other Hormones in Middle-Aged Men: Longitudinal Results from the Massachusetts Male Aging Study.Gradual longitudinal testosterone decline of ~1–2%/year in aging men, providing context for why symptoms develop slowly and may be attributed to normal aging.

Sudden onset of sexual dysfunction or significant change in mood and energy should prompt consideration of other causes — thyroid disease, cardiac conditions, depression, or a medication change — rather than assuming new-onset testosterone deficiency.

How is low testosterone diagnosed?

A proper diagnosis requires compatible symptoms plus confirmed low testosterone on laboratory testing. Testing guidelines specify 1Ref 1Bhasin S, Brito JP, Cunningham GR, et al. (2018).Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline.Recognized symptoms of hypogonadism including sexual and nonspecific symptoms; opioids as a cause of secondary hypogonadism; diagnosis requiring two confirmed morning samples; requirement for compatible symptoms alongside biochemical confirmation2Ref 2Mulhall JP, Trost LW, Brannigan RE, et al. (2018).Evaluation and Management of Testosterone Deficiency: AUA Guideline.Morning testing requirement; confirmatory testing protocol; SHBG measurement when total testosterone is borderline:

• Total testosterone measured in the morning (7–10 a.m.), when levels are at their daily peak
• A low result confirmed on a second separate morning sample before concluding that levels are truly low
• If total testosterone is borderline, measurement of free testosterone and sex hormone-binding globulin (SHBG) adds important context

A morning total testosterone below approximately 300 ng/dL on two occasions in a man with compatible symptoms is the working clinical definition of low testosterone (hypogonadism). The diagnosis is not made from symptoms alone.

Additional testing — LH, FSH, prolactin — determines whether the cause is in the testes themselves (primary hypogonadism) or in the brain's control signals (secondary hypogonadism), which matters for treatment.

What should you do if you think you have low testosterone?

Start with a primary care visit. Your clinician will review your symptoms in context, check for other potential causes (thyroid, iron, sleep quality, mood), and order a morning testosterone level as part of a broader metabolic panel if indicated.

Before the visit, it helps to note: - When symptoms started and whether they are getting worse - Any medications you take, including over-the-counter supplements - Sleep quality and patterns - Any recent significant weight changes or stressors

Gale's primary care clinicians can order the appropriate labs, review them with you, and coordinate with an endocrinologist if needed. Treatment — whether lifestyle changes, addressing another underlying condition, or testosterone therapy when truly indicated — should follow a confirmed diagnosis.