From declining energy and sexual health to surprising new cardiovascular research, here's why low testosterone deserves a closer look.
He's exhausted before the day even begins.
The gym feels harder than it used to. His motivation has disappeared. He's gaining weight despite insisting that nothing about his routine has changed.
Maybe his sex drive isn't what it once was.
Maybe he's noticed changes in his mood, concentration, or confidence.
And when he finally mentions these symptoms, he's told something many men have heard before:
"You're just getting older."
But what if there's more to the story?
Testosterone plays an important role in men's health, influencing sexual function, muscle and bone health, red blood cell production, and other physiological processes.
Although testosterone levels commonly decline with age, clinically significant testosterone deficiency is not something that should automatically be dismissed as normal aging.
Understanding the difference begins with knowing what testosterone actually does—and what happens when levels become consistently low.
The Symptoms Men Don't Always Talk About
When most people hear "low testosterone," they immediately think about sexual performance.
And while testosterone deficiency can affect sexual health, its potential effects extend beyond the bedroom.
Men with testosterone deficiency may experience:
Reduced sex drive or fewer spontaneous erections.
Erectile difficulties.
Decreased muscle mass or strength.
Increased body fat.
Persistent fatigue or reduced endurance.
Changes in mood, motivation, or concentration.
Reduced bone density.
Unexplained anemia.
Fertility concerns.
Not every man will experience these symptoms, and many of them have causes unrelated to testosterone.
Sleep apnea, depression, thyroid disorders, obesity, diabetes, medication effects, and chronic illnesses can produce similar complaints.
That's why symptoms should prompt a thoughtful evaluation—not an automatic testosterone prescription.
The Endocrine Society emphasizes that hypogonadism requires both compatible symptoms and consistently low testosterone measurements (Endocrine Society, 2026).
Why One Testosterone Test Doesn't Tell the Whole Story
Testosterone levels naturally fluctuate.
They're influenced by sleep, illness, time of day, certain medications, and other physiological factors.
For that reason, a single low result doesn't necessarily establish testosterone deficiency.
Clinical guidelines generally recommend measuring total testosterone on two separate mornings before making the diagnosis.
The American Urological Association uses a total testosterone level below 300 ng/dL as a reasonable diagnostic threshold when accompanied by compatible symptoms (American Urological Association, 2018).
Additional testing may include free testosterone when indicated, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and other laboratory studies to help identify the underlying cause.
Sometimes testosterone deficiency originates in the testes.
Other times, the problem involves signaling from the hypothalamus or pituitary gland.
And in some cases, potentially reversible factors such as obesity, medication use, or other health conditions contribute to reduced testosterone levels.
The goal isn't simply to find a low number. It's to understand why that number is low.
Normal Doesn't Always Mean Optimal: Understanding Testosterone Reference Ranges
Here's something many men don't realize.
A testosterone level that falls within a laboratory's reference range doesn't necessarily tell us whether that level is appropriate for every individual.
Laboratory reference ranges are generally established using measurements from a defined population. They help clinicians identify results that fall outside expected limits, but they aren't a personalized measurement of how someone should feel.
Consider two men with different testosterone concentrations.
One may have a total testosterone level of 350 ng/dL and experience no symptoms.
Another may have a similar result but struggle with reduced libido, fatigue, or other concerns that warrant further evaluation.
Does that automatically mean the second man needs testosterone replacement therapy?
No. But it does mean his symptoms deserve investigation.
A result being labeled "normal" shouldn't be the end of the conversation.
Total Testosterone Is Only Part of the Picture
Most routine laboratory reports emphasize total testosterone, but testosterone circulates in several forms.
Some is tightly bound to sex hormone-binding globulin (SHBG), some is loosely bound to albumin, and a small portion circulates as free testosterone.
Changes in SHBG can influence how total testosterone results should be interpreted.
For example, certain men may have total testosterone concentrations within the laboratory reference range while their free testosterone is low.
The Endocrine Society recommends considering free testosterone testing when total testosterone is near the lower limit of normal or when a condition affecting SHBG may be present (Bhasin et al., 2018).
That's why evaluating hormone health sometimes requires looking beyond a single number.
The Difference Between Normal and Optimal
The word optimal gets used frequently in conversations about hormone replacement therapy.
But it's important to understand what it should—and shouldn't—mean.
Optimal testosterone isn't necessarily the highest possible testosterone level.
And there isn't one scientifically established testosterone concentration that guarantees every man will have maximum energy, strength, libido, or well-being.
Instead, individualized treatment involves understanding symptoms, confirming an appropriate diagnosis, identifying contributing conditions, and determining whether treatment provides meaningful clinical benefits without unnecessary risks.
For men with confirmed testosterone deficiency who receive TRT, the American Urological Association recommends targeting the middle portion of the normal physiological range, approximately 450–600 ng/dL, while assessing symptom improvement and safety (Mulhall et al., 2018).
The Endocrine Society similarly recommends maintaining testosterone concentrations in the mid-normal range during treatment (Bhasin et al., 2018).
These are treatment targets—not universal diagnostic thresholds or guarantees of symptom relief.
The goal isn't to chase an impressive laboratory number. It's to achieve safe, evidence-based treatment that improves the health concerns actually attributable to testosterone deficiency.
If testosterone concentrations normalize but symptoms don't improve, the treatment plan should be reassessed rather than automatically increasing the dose.
Treat the Individual, Not Just the Laboratory Report
A comprehensive evaluation considers more than testosterone alone.
Sleep quality, metabolic health, medication use, thyroid function, mental health, cardiovascular risk, fertility goals, and other medical conditions can all influence symptoms and treatment decisions.
Two men with similar laboratory values may ultimately need very different approaches.
One may have confirmed hypogonadism and benefit from testosterone therapy.
Another may have untreated sleep apnea, depression, thyroid disease, or another condition that better explains his symptoms.
A laboratory result is a piece of information. It is not the whole patient.
And that distinction is at the heart of responsible, individualized hormone care.
When Testosterone Replacement Therapy Makes Sense
Testosterone replacement therapy, commonly called TRT, is intended to restore testosterone concentrations in men with appropriately diagnosed hypogonadism.
For selected patients, treatment can improve sexual desire and aspects of sexual function. It may also help address anemia, bone health, or changes in body composition in certain clinical circumstances.
However, benefits vary.
Not every man experiences improvements in energy, mood, strength, or erectile function, and TRT should never be presented as a guaranteed solution to fatigue or aging.
Treatment should involve a discussion of the expected benefits, potential adverse effects, alternative approaches, and ongoing monitoring.
It also requires something that doesn't always receive enough attention:
A conversation about cardiovascular health.
The Heart Question: Does Testosterone Help or Harm?
For years, testosterone therapy has been surrounded by concerns about heart attacks, strokes, and other cardiovascular complications.
Some earlier studies raised safety questions, while others suggested that men with lower testosterone levels experienced higher rates of cardiovascular disease.
But there's an important scientific distinction.
Finding an association between low testosterone and cardiovascular disease does not prove that testosterone deficiency directly causes heart disease.
And it doesn't prove that testosterone replacement prevents it.
To understand the treatment's effects, researchers needed large randomized clinical trials.
That brings us to one of the most important studies in modern testosterone research.
The TRAVERSE Trial Changed the Conversation
In 2023, researchers published the TRAVERSE trial in The New England Journal of Medicine.
The study enrolled 5,246 men between 45 and 80 years old who had symptoms of hypogonadism, consistently low testosterone levels, and either existing cardiovascular disease or an increased cardiovascular risk.
Participants received either testosterone gel or a placebo.
Researchers followed them to evaluate major cardiovascular events, including cardiovascular death, nonfatal heart attack, and nonfatal stroke.
The results challenged some long-standing fears.
What Researchers Found
Major cardiovascular events occurred in:
7.0% of men receiving testosterone therapy
7.3% of men receiving placebo
The trial demonstrated that testosterone therapy was noninferior to placebo for the primary composite cardiovascular outcome in the population studied (Lincoff et al., 2023).
In everyday language, researchers did not find that appropriately administered testosterone therapy caused an unacceptable increase in these major cardiovascular events compared with placebo.
That was significant.
But here's something equally important:
The trial did not demonstrate that testosterone therapy prevents heart attacks or strokes.
The numerical difference between 7.0% and 7.3% does not establish a protective cardiovascular benefit.
And the study identified other safety signals.
Men receiving testosterone experienced higher incidences of atrial fibrillation, pulmonary embolism, and acute kidney injury.
These findings reinforce why testosterone therapy should be individualized and carefully monitored.
What the FDA Changed in 2025
The TRAVERSE findings were important enough to influence federal medication labeling.
On February 28, 2025, the U.S. Food and Drug Administration announced class-wide labeling changes for testosterone products.
After reviewing the cardiovascular trial results, the FDA directed manufacturers to remove language from the boxed warning concerning an increased risk of adverse cardiovascular outcomes.
However, the agency also required updated warnings about increased blood pressure, based on ambulatory blood pressure monitoring studies (U.S. Food and Drug Administration, 2025).
The updated labeling represents an important shift in how cardiovascular safety is communicated.
It does not mean testosterone therapy is risk-free.
It also does not mean men should take testosterone specifically to prevent cardiovascular disease.
In fact, the Endocrine Society reiterated in July 2026 that although recent trials have addressed some safety concerns, important questions about long-term risks remain (Endocrine Society, 2026).
The science is becoming clearer.
But the conversation is far from over.
Why Untreated Low Testosterone Still Deserves Attention
Here's where the issue becomes especially relevant.
Men experiencing legitimate symptoms of testosterone deficiency may spend years assuming that fatigue, sexual changes, or declining physical function are simply unavoidable parts of getting older.
Others may turn to unregulated supplements or hormone products marketed with unrealistic promises.
Neither approach addresses the underlying question.
Is there a medical condition contributing to these symptoms?
When hypogonadism is appropriately diagnosed, treatment may improve meaningful aspects of quality of life.
Even when TRT isn't recommended, the evaluation can uncover other conditions worth treating.
And some men may benefit from addressing reversible contributors before considering testosterone therapy.
The goal shouldn't be to prescribe testosterone to every man who feels tired.
But it shouldn't be to dismiss every man who asks about it, either.
Testosterone Therapy Requires More Than a Prescription
A responsible treatment plan doesn't end when testosterone levels improve.
Follow-up monitoring is essential.
Depending on the individual, this may include reassessing symptoms, testosterone concentrations, hematocrit, blood pressure, and prostate-related considerations.
TRT can increase red blood cell production, sometimes causing an excessive rise in hematocrit.
It can also suppress the body's own testosterone production and sperm production, making fertility counseling particularly important for men who hope to have children.
Certain conditions, including elevated hematocrit, untreated severe obstructive sleep apnea, uncontrolled heart failure, recent major cardiovascular events, and specific prostate-related concerns, may change whether treatment is appropriate.
The objective is to restore physiological testosterone levels when medically indicated—not to pursue unnecessarily high hormone concentrations.
More testosterone does not automatically mean better health.
The Bigger Picture of Men's Health
Men's health conversations often revolve around strength, performance, and physical appearance.
But there is much more at stake.
Sexual well-being.
Mental health.
Energy.
Bone health.
Cardiovascular risk.
Fertility.
And the ability to participate fully in everyday life.
Testosterone is only one part of that picture, but it can be an important one.
As research continues to evolve, we should be willing to challenge outdated assumptions while remaining equally cautious about exaggerated treatment claims.
The evidence supports evaluating men with compatible symptoms, accurately diagnosing testosterone deficiency, and considering treatment when the benefits outweigh the risks.
The cardiovascular findings are reassuring in specific patient populations—but they are not proof that testosterone is a heart-protective medication.
Perhaps the most important message is simpler than any laboratory value or research statistic.
Men deserve to have their health concerns taken seriously.
They deserve accurate information.
And they deserve treatment decisions based on evidence, not stereotypes about aging or promises of a quick fix.
Because getting older may be inevitable. But assuming every change is normal shouldn't be.
— Kayla Brewer-Clements, MSN, APRN, FNP-C
References
American Urological Association. (2018). Evaluation and management of testosterone deficiency: AUA guideline. https://www.auanet.org/guidelines-and-quality/guidelines/testosterone-deficiency-guideline
Bhasin, S., Brito, J. P., Cunningham, G. R., Hayes, F. J., Hodis, H. N., Matsumoto, A. M., Snyder, P. J., Swerdloff, R. S., Wu, F. C., & Yialamas, M. A. (2018). Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology & Metabolism, 103(5), 1715–1744. https://doi.org/10.1210/jc.2018-00229
Endocrine Society. (2026, July 16). Statement on testosterone replacement therapy. https://www.endocrine.org/news-and-advocacy/news-room/2026/statement-on-testosterone%20replacement-therapy
Lincoff, A. M., Bhasin, S., Flevaris, P., Mitchell, L. M., Basaria, S., Boden, W. E., Cunningham, G. R., Granger, C. B., Khera, M., Thompson, I. M., Jr., Wang, Q., Wolski, K., Davey, D., Kalahasti, V., Khan, N., Miller, M. G., Snabes, M. C., Chan, A., Dubcenco, E., . . . Nissen, S. E. (2023). Cardiovascular safety of testosterone-replacement therapy. The New England Journal of Medicine, 389(2), 107–117. https://doi.org/10.1056/NEJMoa2215025
Mulhall, J. P., Trost, L. W., Brannigan, R. E., Kurtz, E. G., Redmon, J. B., Chiles, K. A., Lightner, D. J., Miner, M. M., Murad, M. H., Nelson, C. J., Platz, E. A., Ramanathan, L. V., & Lewis, R. W. (2018). Evaluation and management of testosterone deficiency: AUA guideline. The Journal of Urology, 200(2), 423–432. https://doi.org/10.1016/j.juro.2018.03.115
U.S. Food and Drug Administration. (2025, February 28). FDA issues class-wide labeling changes for testosterone products. https://www.fda.gov/drugs/drug-alerts-and-statements/fda-issues-class-wide-labeling-changes-testosterone-products
Educational disclaimer: This article is intended for general health education and does not constitute individualized medical advice. Testosterone replacement therapy requires appropriate diagnosis, clinical assessment, and monitoring. Patients should discuss potential benefits, risks, and alternatives with their healthcare professional.
