Low Testosterone in Men: Symptoms, Health Risks, and the Importance of Testosterone Replacement

Testosterone plays an important role in men's sexual health, muscle mass, bone strength, red blood cell production, energy, mood, and physical function. When testosterone levels fall below the normal range, some men experience symptoms that affect their quality of life and long-term health.

Although testosterone naturally declines with age, clinically significant testosterone deficiency, also calledmale hypogonadism, is not an inevitable or harmless part of aging. Identifying and treating confirmed deficiency may help improve symptoms and address certain health consequences.

Symptoms of Low Testosterone

Symptoms can develop gradually and may be attributed to aging, stress, or other health conditions.

Sexual symptoms

• Reduced libido or sexual desire
• Fewer spontaneous or morning erections
• Erectile dysfunction
• Reduced sexual satisfaction
• Infertility or reduced sperm production

Energy and physical symptoms

• Persistent fatigue or low energy
• Reduced muscle mass and strength
• Increased body fat, particularly around the abdomen
• Reduced exercise capacity or physical endurance
• Decreased bone density and increased fracture risk
• Unexplained anemia

Mental and emotional symptoms

• Depressed mood or loss of interest in activities
• Reduced motivation and drive
• Irritability or increased emotional sensitivity
• Difficulty concentrating or feeling mentally “slowed down”
• Reduced sense of well-being
• Changes in confidence or self-esteem

These symptoms are not specific to low testosterone. Sleep disorders, thyroid dysfunction, anemia, medication effects, depression, chronic illness, and other factors can cause similar problems.

Health Risks Associated With Low Testosterone

1. Muscle Loss, Increased Body Fat, and Metabolic Health

Testosterone helps maintain lean muscle mass, strength, and healthy body composition. Deficiency can contribute to reduced muscle mass, increased fat mass, and impaired physical function.

In the Testosterone Trials, older men with low testosterone who received testosterone treatment experienced improvements in sexual function, mood-related measures, and some aspects of physical function. Effects varied by outcome, and treatment did not consistently improve walking distance.

Human clinical study:

Snyder PJ, et al. Effects of Testosterone Treatment in Older Men.New England Journal of Medicine. 2016;374:611–624.https://doi.org/10.1056/NEJMoa1506119

2. Bone Density and Fracture Risk

Testosterone contributes to bone maintenance, partly through its conversion to estradiol. Low levels can contribute to reduced bone density and may increase skeletal fragility.

However, improvements in bone density do not automatically translate into fewer fractures. In a large fracture substudy of the TRAVERSE trial, testosterone treatment did not reduce clinical fractures compared with placebo; fractures were actually more frequent in the testosterone group. This underscores the importance of evaluating bone health independently rather than assuming testosterone replacement prevents fractures.

Human clinical study:

Snyder PJ, et al. Testosterone Treatment and Fractures in Men with Hypogonadism.New England Journal of Medicine. 2024;390:203–211.https://doi.org/10.1056/NEJMoa2308836

3. Anemia and Red Blood Cell Production

Testosterone stimulates red blood cell production. Low testosterone can contribute to otherwise unexplained anemia, potentially worsening fatigue, weakness, and exercise intolerance.

In a large randomized clinical trial involving men with hypogonadism and anemia, testosterone treatment increased the likelihood of anemia resolving compared with placebo.

Human clinical study:

Roy CN, et al. Association of Testosterone Levels With Anemia in Older Men: A Controlled Clinical Trial.JAMA Network Open. 2023.https://pubmed.ncbi.nlm.nih.gov/37889486/

4. Mental Health, Depression, and Emotional Well-Being

Testosterone influences the brain systems involved in mood, motivation, sexual desire, and emotional well-being. Some men with low testosterone report depressed mood, reduced motivation, irritability, low energy, and diminished interest in activities they previously enjoyed.

Low testosterone and depression can also influence one another. Chronic illness, obesity, poor sleep, stress, and depression may contribute to lower testosterone, while testosterone deficiency may worsen symptoms in some susceptible men. The relationship is complex, and finding a low testosterone level does not establish that it is the cause of depression.

Human clinical studies suggest a potential benefit of treatment in selected men:

• 2019 systematic review and meta-analysis: Walther and colleagues analyzed 27 randomized, placebo-controlled trials involving 1,890 men. Testosterone treatment was associated with a statistically significant but modest reduction in depressive symptoms compared with placebo. The studies varied in participants, doses, and methods, so the results do not establish that testosterone is an effective antidepressant for every man with low testosterone.
  Walther A, Breidenstein J, Miller R. Association of Testosterone Treatment With Alleviation of Depressive Symptoms in Men: A Systematic Review and Meta-analysis. JAMA Psychiatry. 2019;76(1):31–40. https://doi.org/10.1001/jamapsychiatry.2018.2734
• 2024 TRAVERSE analysis: In an analysis of more than 5,200 middle-aged and older men with hypogonadism and cardiovascular disease or elevated cardiovascular risk, testosterone treatment was associated with small improvements in mood and energy compared with placebo among men with depressive symptoms and in the overall study population. It did not significantly improve every mental health measure, and men meeting strict criteria for persistent depressive disorder did not show a clear treatment benefit; that subgroup was small.
  Bhasin S, et al. Depressive Syndromes in Men With Hypogonadism in the TRAVERSE Trial: Response to Testosterone-Replacement Therapy. Journal of Clinical Endocrinology & Metabolism . 2024. https://pubmed.ncbi.nlm.nih.gov/38205962/
• Randomized trial in older men with subthreshold depression: In a 12-week placebo-controlled study, testosterone-treated men experienced a greater reduction in depression scores and a higher remission rate than men receiving placebo. The study was relatively small, and its findings cannot be generalized to all forms of depression.
  Snyder PJ, et al. A Randomized, Double-Blind, Placebo-Controlled Study of Testosterone Treatment in Hypogonadal Older Men With Subthreshold Depression. Journal of Clinical Psychopharmacology. 2009. https://pubmed.ncbi.nlm.nih.gov/19653976/

What this means:Testosterone replacement may support mood and energy in some men with confirmed testosterone deficiency, but the average antidepressant effect appears modest and findings are not uniform. Testosterone should not replace appropriate evaluation and treatment for depression, which may include psychotherapy, medication, and addressing sleep, lifestyle, and underlying medical conditions.

5. Cardiovascular Disease and Congestive Heart Failure

Testosterone is involved in muscle function, body composition, red blood cell production, and metabolic health. Observational studies have associated low testosterone with obesity, type 2 diabetes, cardiovascular disease, and heart failure. However, these relationships are complicated: cardiovascular disease and chronic illness can themselves suppress testosterone, and observational associations do not prove that low testosterone directly causes these conditions.

What does human clinical research show about testosterone replacement and cardiovascular risk?

The large TRAVERSE randomized trial evaluated testosterone treatment in more than 5,200 men aged 45–80 with symptoms of hypogonadism, two low testosterone measurements, and existing or elevated cardiovascular risk. Major cardiovascular events, including cardiovascular death, nonfatal heart attack, and nonfatal stroke, occurred in 7.0% of the testosterone group and 7.3% of the placebo group. Testosterone was noninferior to placebo for these events in the population studied. However, atrial fibrillation, acute kidney injury, and pulmonary embolism occurred more frequently in the testosterone group.

Lincoff AM, et al. Cardiovascular Safety of Testosterone-Replacement Therapy.New England Journal of Medicine. 2023;389:107–117.https://doi.org/10.1056/NEJMoa2215025

Testosterone and congestive heart failure (CHF)

Low testosterone is relatively common in men with chronic heart failure and has been associated with reduced exercise tolerance, muscle weakness, fatigue, and poorer functional status. Some of these symptoms may overlap with testosterone deficiency, while heart failure itself may contribute to hormonal changes.

Small randomized trials and systematic reviews have explored testosterone treatment in men with heart failure. Some findings suggest possible improvements in certain measures of aerobic capacity or physical performance, but results have been inconsistent. Studies have not established that testosterone replacement reduces hospitalizations or mortality, improves heart function reliably, or treats heart failure itself.

Relevant reviews include:

• Testosterone replacement therapy in hypogonadal male patients with hypogonadism and heart failure: a meta-analysis of randomized controlled studies. 2021. https://pubmed.ncbi.nlm.nih.gov/33781026/
• Testosterone replacement therapy in heart failure: A systematic review of randomized controlled trials. 2025. https://pubmed.ncbi.nlm.nih.gov/40234375/

Clinical perspective:Men with heart failure and symptoms of low testosterone may warrant evaluation for hormonal deficiency. However, testosterone is not an established treatment for CHF, and fluid retention can be a concern, particularly in patients with poorly controlled heart failure. Treatment decisions require individualized assessment and coordination with the clinician managing the heart condition.

When Is Testosterone Replacement Appropriate?

Testosterone replacement therapy (TRT) may be appropriate for men who have both symptoms consistent with testosterone deficiency and consistently low testosterone levels confirmed by laboratory testing.

Diagnosis generally requires:

• A compatible history and physical examination.
• At least two separate early-morning testosterone measurements showing low levels.
• Additional testing, when appropriate, to investigate the underlying cause, including LH, FSH, prolactin, and other relevant laboratory markers.

Total testosterone alone may not tell the full story. Sex hormone-binding globulin (SHBG), free testosterone, medications, obesity, sleep disorders, and other health conditions may affect the interpretation of results.

Potential Benefits of Testosterone Replacement

For appropriately selected men with confirmed hypogonadism, treatment may improve:

• Sexual desire and some aspects of sexual function
• Lean body mass and, in some cases, strength
• Bone density
• Anemia associated with testosterone deficiency
• Certain symptoms of low mood, energy, or well-being

The extent of benefit varies, and not all symptoms attributed to low testosterone improve with treatment. Testosterone replacement is not proven to prevent cardiovascular disease, reliably treat congestive heart failure, or eliminate the risk of fractures.

Important Risks and Monitoring

Testosterone therapy requires medical supervision. Potential concerns include elevated hematocrit, acne, infertility from suppression of sperm production, fluid retention, worsening of certain urinary symptoms, and changes in prostate-specific antigen (PSA). Cardiovascular and other risks should be discussed based on the patient's medical history.

Men considering treatment should discuss fertility goals, prostate health, sleep apnea, blood counts, cardiovascular conditions, and appropriate follow-up testing with their clinician. Testosterone treatment is generally avoided in men planning near-term fertility and may be contraindicated in certain medical circumstances.

Conclusion

Testosterone is important for more than libido. It contributes to muscle and bone health, red blood cell production, mood, energy, and physical function. Low testosterone is associated with several health concerns, including depressive symptoms, metabolic disease, cardiovascular disease, and heart failure, although these associations do not always establish cause and effect.

Human clinical studies support benefits of testosterone replacement for selected outcomes in men with confirmed hypogonadism. Some evidence also suggests modest improvements in depressive symptoms, mood, and energy, but testosterone is not a universal treatment for depression or cardiovascular disease.

The most appropriate approach is to identify the cause of symptoms, confirm testosterone deficiency with proper testing, consider both benefits and risks, and monitor treatment carefully. The goal is to treat a documented hormonal deficiency, not simply to raise testosterone levels in every man experiencing fatigue, low mood, or age-related changes.

CONTACT VALLEY INTEGRATIVE HEALTH TODAY

Devin Wilson, ND, is a licensed Naturopathic Doctor and owner of Valley Integrative Health, LLC, in Ashland, Oregon. With over a decade of clinical experience, including two years of training with a physician affiliated with Johns Hopkins and Yale, Dr. Wilson integrates naturopathic and modern medical approaches with selected advanced therapies. He has completed advanced training in anti-aging medicine and bioidentical hormone therapy through the American Academy of Anti-Aging Medicine (A4M). Dr. Wilson has also previously worked at a specialized stem cell and anti-aging clinic. His goal is to help patients re-establish, maintain, and optimize their health through an individualized, patient-centered approach.