Testosterone Replacement Therapy: The Real Problem Isn’t Testosterone—It’s Testosterone Deficiency
For decades, testosterone has been one of the most misunderstood hormones in medicine. Headlines have warned about heart attacks, prostate cancer, aggression, and dangerous side effects, causing many men with legitimate testosterone deficiency to avoid treatment.
However, modern medical research tells a very different story.
The goal of testosterone replacement therapy (TRT) is not to create unnaturally high testosterone levels or enhance athletic performance. Instead, TRT is designed to restore testosterone to a normal physiologic range in men with documented hypogonadism and symptoms of deficiency.
Increasingly, research suggests that chronically low testosterone may carry greater health consequences than appropriately monitored testosterone replacement.
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Myth #1: Testosterone Causes Heart Attacks
One of the most common misconceptions surrounding testosterone replacement is that it increases the risk of heart attack or stroke.
This concern originated from several observational studies published more than a decade ago. Because of these concerns, the FDA required manufacturers to perform a large randomized cardiovascular safety trial.
The result was the TRAVERSE Trial, the largest and highest-quality testosterone safety study ever conducted.
Researchers followed more than 5,200 men with documented testosterone deficiency who also had known cardiovascular disease or multiple cardiovascular risk factors.
The findings were reassuring.
Testosterone replacement did not increase the risk of:
• Heart attack
• Stroke
• Cardiovascular death
Testosterone therapy was found to be non-inferior to placebo for major adverse cardiovascular events.
Following publication of the TRAVERSE Trial, the FDA updated testosterone labeling in 2025 by removing the boxed warning suggesting testosterone increases cardiovascular risk. The FDA did add recommendations regarding blood pressure monitoring because TRT can increase blood pressure in some individuals.
Bottom line: Modern evidence no longer supports the blanket belief that medically supervised testosterone replacement increases the risk of heart attack or stroke in appropriately selected patients.
References
Lincoff AM, et al. Cardiovascular Safety of Testosterone-Replacement Therapy. New England Journal of Medicine. 2023;389:107-117.
U.S. Food and Drug Administration. FDA Class-Wide Labeling Changes for Testosterone Products. 2025.
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Myth #2: Testosterone Causes Prostate Cancer
For decades physicians believed testosterone “fed” prostate cancer.
Current research has challenged this long-held belief.
Although testosterone therapy is not recommended for men with untreated prostate cancer, there is no convincing evidence that restoring testosterone to normal physiologic levels causes prostate cancer in properly screened men.
Instead, current guidelines recommend:
• Baseline PSA testing when appropriate
• Routine prostate evaluation
• Continued monitoring during therapy
rather than avoiding testosterone altogether.
Bottom line: Testosterone replacement should be monitored appropriately, but current evidence does not support the idea that physiologic TRT causes prostate cancer.
Reference
Morgentaler A, et al. Testosterone Therapy in Men: Clinical Update. New England Journal of Medicine. 2025.
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Myth #3: Higher Testosterone Is Better
Some people have replaced one myth with another.
The goal of testosterone replacement is not to achieve the highest testosterone level possible.
It is to restore testosterone to a healthy physiologic range while improving symptoms.
Excessively high testosterone levels can increase the likelihood of:
• Elevated hematocrit
• High blood pressure
• Acne
• Infaired fertility
• Fluid retention
• Estrogen-related side effects
Responsible testosterone therapy is about finding the right level, not the highest level.
Bottom line: Too much testosterone can be harmful—but so can too little.
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Myth #4: Low Testosterone Is Only About Sex
While testosterone certainly influences libido and erectile function, its effects extend far beyond sexual health.
Testosterone plays an important role in:
• Maintaining muscle mass
• Bone strength
• Red blood cell production
• Exercise recovery
• Energy levels
• Mood
• Cognitive function
• Healthy body composition
Men with chronically low testosterone commonly experience:
• Fatigue
• Loss of muscle
• Increased abdominal fat
• Reduced motivation
• Decreased exercise tolerance
• Erectile dysfunction
• Low libido
• Osteoporosis
• Anemia
These symptoms should never be dismissed as simply “getting older.”
Reference
Morgentaler A, et al. New England Journal of Medicine. 2025.
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Myth #5: Low Testosterone Is Just Part of Aging
Although testosterone gradually declines with age, symptomatic testosterone deficiency is not simply a normal consequence of aging.
The Endocrine Society recommends diagnosing testosterone deficiency only when BOTH are present:
• Symptoms consistent with hypogonadism
• Repeatedly low morning testosterone levels
Treating a laboratory value without symptoms is inappropriate.
Ignoring symptoms because someone is getting older is equally inappropriate.
Reference
Endocrine Society Clinical Practice Guideline: Testosterone Therapy in Men With Hypogonadism.
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The Real Issue: What Happens When Testosterone Stays Too Low?
Much of the public conversation focuses on the potential risks of testosterone replacement.
Far less attention is given to the consequences of untreated testosterone deficiency.
Research has associated chronically low testosterone with:
• Loss of muscle mass
• Increased visceral fat
• Reduced bone density
• Frailty
• Sexual dysfunction
• Reduced quality of life
• Anemia
• Poor physical performance
Low testosterone may also be associated with obesity, diabetes, metabolic syndrome, chronic illness, opioid use, pituitary disorders, and testicular disease.
Rather than simply prescribing testosterone, physicians should identify and address the underlying cause whenever possible.
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Testosterone Is Not a Miracle Drug
Responsible physicians recognize that testosterone replacement is not appropriate for everyone.
TRT should never be prescribed simply because someone feels tired.
Before starting therapy, clinicians should:
✓ Confirm low testosterone with repeat morning laboratory testing
✓ Evaluate symptoms
✓ Identify reversible causes
✓ Discuss fertility goals
✓ Screen for contraindications
✓ Review cardiovascular risk
✓ Develop an ongoing monitoring plan
Testosterone replacement is a medical treatment—not a shortcut to better health.
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Safe Testosterone Therapy Requires Monitoring
Patients receiving testosterone replacement should undergo routine follow-up that may include:
• Testosterone levels
• Complete blood count
• Hematocrit
• Blood pressure
• PSA (when appropriate)
• Symptom assessment
• Side effect monitoring
Routine follow-up allows physicians to optimize treatment while minimizing risk.
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The Bottom Line
The conversation surrounding testosterone replacement has changed dramatically over the past several years.
The largest randomized clinical trial ever performed demonstrated no increase in heart attack, stroke, or cardiovascular death among appropriately selected men receiving testosterone replacement.
In response, the FDA removed the boxed warning suggesting testosterone therapy increases cardiovascular risk while emphasizing continued blood pressure monitoring.
The goal of testosterone replacement is not to create high testosterone levels.
The goal is to restore normal physiologic hormone levels in men with documented deficiency while carefully monitoring safety.
Perhaps the biggest misconception is that testosterone itself is the problem.
For many men, the greater health risk is living for years with untreated testosterone deficiency.
When properly diagnosed and medically supervised, testosterone replacement can improve symptoms, quality of life, sexual health, body composition, bone density, and overall well-being.
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References
Lincoff AM, et al. Cardiovascular Safety of Testosterone-Replacement Therapy. New England Journal of Medicine. 2023;389:107-117.
Morgentaler A, et al. Testosterone Therapy in Men. New England Journal of Medicine. 2025.
Endocrine Society. Testosterone Therapy for Hypogonadism Clinical Practice Guideline. 2018 (current guideline).
American Urological Association. Testosterone Deficiency Guideline. Updated 2024.
U.S. Food and Drug Administration. Class-Wide Labeling Changes for Testosterone Products.
