Will Low Testosterone Make You Tired? Signs and When to Get Tested

Waking up drained after a full night’s rest confuses most men, especially when nothing in their routine has changed. Fatigue can have multiple causes, not just low testosterone, but this hormone remains one of the most overlooked contributors. A cross-sectional study of adult patients with unexplained tiredness found a significant negative correlation between testosterone levels and fatigue severity. Patients with low testosterone scored far higher on fatigue scales than those with normal levels (Khan et al., 2024).

What is Testosterone and Why Does it Matter for Energy?

Testosterone regulates far more than sex drive. It plays a vital role in sexual function, body composition, mood, and multiple organ systems, and a decline in this hormone is associated with reduced physical performance, sarcopenia, cognitive impairment, and depression (Corona et al., 2013).

How Testosterone Regulates Energy Production in the Body

Testosterone deficiency syndrome develops when consistently low serum testosterone appears alongside symptoms affecting energy, muscle mass, and metabolic function, since the hormone directly influences how the body sustains physical output across multiple systems (Tostain & Blanc, 2008).

Normal Testosterone Levels vs. Testosterone Deficiency

In many older men, testosterone levels are low because production declines gradually with normal aging, but clinicians increasingly recognize that younger men can also present with testosterone deficiency, particularly when sexual dysfunction or metabolic disease is also present (Corona et al., 2013). Screening tools built for predicting low testosterone in aging men show that combining specific symptom clusters with lab values improves diagnostic accuracy over relying on a single sign (Tajar et al., 2016).

Can Low Testosterone Cause Fatigue?

Chronic fatigue is a common sign of low testosterone, and research measuring fatigue severity on a numeric rating scale found patients with testosterone below 300 ng/dL reported significantly higher fatigue scores than those with normal levels (Khan et al., 2024). Men should avoid jumping straight to testosterone therapy without first ruling out thyroid problems, since both conditions produce nearly identical feelings of being drained. Symptoms of low testosterone include fatigue and low energy levels frequently enough that researchers now treat unexplained tiredness as a legitimate reason to screen hormone status rather than a symptom to dismiss.

The Link Between Low Testosterone and Chronic Fatigue

Long-term testosterone replacement therapy exceeding one year has been associated with significantly lower fatigue scores in treated patients, suggesting sustained hormone correction plays a measurable role in reducing chronic tiredness (de Almeida Ferreira et al., 2022). Low testosterone is one of the most common contributors to chronic fatigue in men reporting a consistent cluster of symptoms together, though this connection deserves careful lab confirmation rather than assumption based on tiredness alone, and chronic fatigue often signals low testosterone levels strongly enough that doctors treat it as a legitimate reason to order labs.

Other Factors That Cause Fatigue Besides Low Testosterone

Testosterone deficiency often overlaps with other chronic conditions, including opioid use, frailty, and dialysis-related muscle wasting, all of which independently produce fatigue and complicate diagnosis (Bawor et al., 2025). Low testosterone is associated with frailty, muscle wasting, and increased fatigue in patients receiving hemodialysis, underscoring that hormone deficiency frequently compounds other underlying illnesses rather than acting alone.

Signs and Symptoms of Low Testosterone Beyond Tiredness

Testosterone deficiency syndrome frequently presents with nonspecific symptoms that vary by age and coexisting illness, which is exactly why diagnosis relies on symptoms and blood tests appearing together rather than either alone (Tostain & Blanc, 2008).

Testosterone and Mood Changes

Testosterone plays a significant role in mood regulation, modulating serotonergic, dopaminergic, and GABAergic systems in brain regions tied to emotional stability, and its deficiency may contribute directly to depressive symptoms (Deshmukh et al., 2026). Testosterone replacement therapy improves mood, energy, and libido in hypogonadal men, though evidence in men with normal baseline levels remains mixed, which is worth talking through with a doctor before assuming hormone therapy will resolve mental health concerns on its own.

Testosterone and Trouble Concentrating

A large systematic review of randomized controlled trials found inconsistent evidence for testosterone’s effect on cognition specifically, meaning trouble concentrating attributed to low testosterone should be evaluated alongside other possible causes rather than assumed (Huo et al., 2016).

How Low Testosterone Affects the Body

Testosterone deficiency syndrome affects multiple organ systems simultaneously, and screening guidance recommends evaluating men with sexual dysfunction, low physical activity, abdominal obesity, loss of muscle mass and strength, or diabetes for the condition (Tostain & Blanc, 2008).

Testosterone and Muscle Mass Loss

Testosterone supplementation consistently increased muscle strength across the studies reviewed, confirming a direct physiological link between hormone levels and muscle mass maintenance even though effects on broader physical function were less consistent (Huo et al., 2016).

Testosterone and Increased Body Fat

Low testosterone is linked to visceral obesity and metabolic risk factors, and men presenting with this combination should be screened for testosterone deficiency according to clinical treatment guidelines (Corona et al., 2013).

Testosterone and Bone Density

Testosterone deficiency is associated with osteoporosis, since the hormone supports bone mineral density alongside muscle and metabolic function, making bone health assessment relevant for men with confirmed low levels (Corona et al., 2013).

Testosterone and Sexual Health

Testosterone directly affects sexual motivation and erectile function. Low libido, reduced sex drive, and erectile dysfunction are all consistently linked to low testosterone across multiple studies (Corona et al., 2013). When testosterone levels drop, energy levels often decrease in tandem, and men frequently report feeling drained alongside a noticeable decline in sexual desire rather than one symptom appearing in isolation. A separate randomized trial found sexual desire scores improved modestly among hypogonadal patients receiving testosterone replacement, though effects on broader quality of life were limited (Del Fabbro et al., 2013).

Testosterone and Sleep Quality

Low testosterone can increase the risk of sleep disturbances, and testosterone deficiency syndrome is specifically linked to sleep apnea in the research literature, disrupting a man’s ability to get enough sleep even when bedtime hours seem sufficient (Corona et al., 2013). Testosterone levels naturally peak during deep sleep cycles, so poor sleep quality and low testosterone often reinforce each other in a cycle that makes a good night’s sleep harder to achieve without intervention, and testosterone levels drop further with each night of disrupted rest.

When to Get Tested for Low Testosterone

The Urology Care Foundation, the official patient education arm of the American Urology Association, notes there is no strong evidence that testosterone therapy will improve every symptom attributed to it, including energy and tiredness, which makes proper testing and diagnosis essential before starting treatment (Urology Care Foundation, n.d.).

Testosterone Blood Test Basics

Diagnosis of testosterone deficiency syndrome requires symptoms and signs to be present simultaneously with a consistently abnormal testosterone level, since a single low reading without symptoms does not confirm the condition (Tostain & Blanc, 2008).

Testosterone Levels That Indicate Deficiency

A cross-sectional study found the frequency of low testosterone, defined as levels below 300 ng/dL, reached 40 percent among adult patients presenting with unexplained fatigue, with average levels in the low group measuring roughly half those of patients with normal testosterone (Khan et al., 2024).

Testosterone Therapy as a Treatment Option

Testosterone deficiency is highly prevalent, and though symptoms are often successfully managed with testosterone replacement therapy, accurate diagnosis before treatment remains essential to avoid unnecessary intervention (Anaissie et al., 2017). TRT Colombia connects patients with English-speaking doctor-allies across six major Colombian cities who guide this diagnostic and treatment process individually.

Benefits of Testosterone Replacement Therapy

A one-year randomized clinical trial combining testosterone with resistance training found meaningful improvements in physical performance and reduced fatigue among frail older men with hypogonadism, supporting therapy paired with structured exercise as a treatment approach for men hoping to increase testosterone levels (Hansen et al., 2024). Providers within the TRT Colombia network offering testosterone replacement therapy for men evaluate each case individually, while a separate track exists through testosterone replacement therapy for women for documented hormonal imbalance.

What to Expect During Testosterone Therapy

Benefits and risks of testosterone therapy should be carefully assessed on an individual basis, particularly in older men, and prospective long-term studies are still needed before expanding screening criteria further (Corona et al., 2013). Routine checkups remain part of responsible treatment given this ongoing need for monitoring, and men should never treat testosterone therapy as a one-time fix.

Lifestyle changes support healthy testosterone alongside or instead of medication. Resistance training paired with testosterone therapy improved physical performance and fatigue outcomes over a full year in frail older men, showing regular exercise compounds the value of hormonal treatment rather than replacing it (Hansen et al., 2024). Men looking to increase testosterone naturally should prioritize weight management, since a bi-directional Mendelian randomization study of over 7,000 men found a causal effect of body mass index on serum testosterone, with a body weight reduction shifting BMI from 30 to 25 producing roughly a 13 percent increase in testosterone (Bekaert et al., 2017). Chronic stress elevates cortisol, and controlled research has shown that cortisol directly suppresses testosterone secretion by acting on the testis itself, decreasing circulating testosterone levels within hours of cortisol elevation (Cumming et al., 1983). Men managing high blood pressure, diabetes, or heart disease alongside low testosterone should discuss any exercise or dietary changes with a doctor first, since a large prospective cohort study found men with a higher cortisol-to-testosterone ratio faced an increased risk of ischemic heart disease, an association driven largely by insulin resistance (Smith et al., 2005).

FAQs

Can low testosterone really cause constant tiredness?
Research shows a significant correlation between low testosterone and fatigue severity, though fatigue has many possible causes, so testing remains the only reliable way to confirm the connection in an individual case.

What testosterone level is considered low?
Clinical studies commonly define low testosterone as levels below 300 ng/dL, though symptom presentation can vary based on age and overall health.

How is low testosterone diagnosed?
Diagnosis requires consistent symptoms alongside an abnormally low testosterone reading confirmed through blood testing, since either factor alone is not sufficient for a diagnosis.

Does testosterone therapy have side effects and require monitoring?
Yes, benefits and risks require careful assessment on an individual basis, particularly in older men, which is why routine checkups accompany any treatment plan.

Can lifestyle changes alone raise low testosterone?
Weight management and stress reduction have shown measurable effects on testosterone levels in clinical research, though lifestyle changes alone may not be sufficient for men with confirmed deficiency, and testosterone therapy combined with resistance training has shown the strongest results in trials to date.

References:

Anaissie, J., DeLay, K. J., Wang, W., Diaz, V., & Hellstrom, W. J. G. (2017). Testosterone deficiency in adults and corresponding treatment patterns across the globe. Translational Andrology and Urology, 6(2), 183–191. https://pmc.ncbi.nlm.nih.gov/articles/PMC5422691/

Bawor, M., et al. (2025). Low testosterone among males in opioid agonist therapy and its association with fatigue and psychological distress. Journal of the Endocrine Society. https://academic.oup.com/jes/advance-article/doi/10.1210/jendso/bvaf114/8177197

Bekaert, M., et al. (2017). Causal relationship between obesity and serum testosterone status in men: A bi-directional Mendelian randomization analysis. PLOS ONE, 12(4), e0176277. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0176277

Corona, G., Rastrelli, G., Monami, M., Guay, A., Buvat, J., Sforza, A., Forti, G., Mannucci, E., & Maggi, M. (2013). Testosterone deficiency in men: Systematic review and standard operating procedures for diagnosis and treatment. Journal of Sexual Medicine, 10(1), 26–36. https://pubmed.ncbi.nlm.nih.gov/22971200/

Cumming, D. C., Quigley, M. E., & Yen, S. S. (1983). Acute suppression of circulating testosterone levels by cortisol in men. Journal of Clinical Endocrinology & Metabolism, 57(3), 671–673. https://pubmed.ncbi.nlm.nih.gov/6348068/

de Almeida Ferreira, M., et al. (2022). Long-term testosterone replacement therapy reduces fatigue in men with hypogonadism. https://pmc.ncbi.nlm.nih.gov/articles/PMC8823386/

Del Fabbro, E., Garcia, J. M., Dev, R., Hui, D., Williams, J., Engineer, D., Palmer, J. L., Schover, L., & Bruera, E. (2013). Testosterone replacement for fatigue in hypogonadal ambulatory males with advanced cancer: A preliminary double-blind placebo-controlled trial. Supportive Care in Cancer, 21(9), 2599–2607. https://pubmed.ncbi.nlm.nih.gov/23653013/

Deshmukh, S., et al. (2026). The interplay between testosterone and depression: Bridging research, clinical applications, and health: A narrative review. https://pubmed.ncbi.nlm.nih.gov/42089747/

Hansen, M., et al. (2024). Testosterone and resistance training improved physical performance and reduced fatigue in frail older men: 1 year follow-up of a randomized clinical trial. Aging Male, 27(1). https://www.tandfonline.com/doi/full/10.1080/13685538.2024.2403519

Huo, S., Scialli, A. R., McGarvey, S., Hill, E., Tügertimur, B., Hogenmiller, A., Fugh-Berman, A., & Scialli, A. R. (2016). Treatment of men for “low testosterone”: A systematic review. PLOS ONE, 11(9), e0162480. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0162480

Khan, A., et al. (2024). The relationship between low testosterone levels and asthenia in adult patients: An original study. Journal of Postgraduate Medical Institute, 38(4). https://jpmi.org.pk/index.php/jpmi/article/view/3488

Low testosterone is associated with frailty, muscle wasting and increased fatigue in hemodialysis patients. (2019). Nephrology Dialysis Transplantation, 34(5), 802–810. https://academic.oup.com/ndt/article/34/5/802/5063538

Smith, G. D., Ben-Shlomo, Y., Beswick, A., Yarnell, J., Lightman, S., & Elwood, P. (2005). Cortisol, testosterone, and coronary heart disease: Prospective evidence from the Caerphilly study. Circulation, 112(3), 332–340. https://www.ahajournals.org/doi/10.1161/circulationaha.104.489088

Tajar, A., et al. (2016). Predicting low testosterone in aging men: A systematic review. PLOS ONE. https://pmc.ncbi.nlm.nih.gov/articles/PMC5026531/

Tostain, J. L., & Blanc, F. (2008). Testosterone deficiency: A common, unrecognized syndrome. Nature Clinical Practice Urology, 5(7), 388–396. https://www.nature.com/articles/ncpuro1167

Urology Care Foundation. (n.d.). Low testosterone: Symptoms, diagnosis & treatment. https://www.urologyhealth.org/urology-a-z/l/low-testosterone