The Truth About Testosterone Therapy

Testosterone replacement therapy (TRT) carries a lot of baggage — some of it earned, most of it outdated. If you've researched low testosterone treatment and come away more confused than when you started, you're not alone. Here's what the current evidence actually says about the four claims we hear most.

Myth #1: "It Causes Cancer"

This belief traces back to research from the 1940s suggesting that lowering testosterone slowed prostate cancer growth — which got extrapolated, incorrectly, into the idea that raising testosterone must cause it. More recent, better-designed studies haven't supported that leap. Testosterone therapy has not been shown to cause prostate cancer in men without pre-existing disease.

That said, this isn't a blanket green light. Men with active or suspected prostate cancer are not candidates for TRT, which is exactly why a PSA test and prostate health review are part of the workup before starting treatment, and part of ongoing monitoring once you're on it.

Myth #2: "It Causes Heart Attacks"

This is the most legitimately debated of the four. Concern grew from a handful of earlier studies with real design flaws, and the FDA added a cardiovascular warning label as a precaution. Since then, larger and more rigorous trials — including a major 2023 cardiovascular safety trial specifically designed to answer this question — found no significant increase in heart attack, stroke, or cardiovascular death among men on properly monitored testosterone therapy compared to those who weren't.

The honest answer is that TRT isn't risk-free for everyone, which is why a cardiovascular risk assessment and bloodwork — including hematocrit, which can rise on therapy — happen before treatment starts and get monitored throughout.

Myth #3: "It Makes People Aggressive"

The "roid rage" reputation comes almost entirely from anabolic steroid abuse — doses many times higher than what's used medically, often stacked with multiple compounds, taken without medical supervision. That's a fundamentally different scenario than physician-monitored TRT, which is dosed to bring testosterone back into a normal physiological range, not push it above it.

At appropriate therapeutic doses, the evidence doesn't support a significant aggression effect. If anything, many patients report the opposite — less irritability, more even mood — once chronically low testosterone is corrected.

Myth #4: "It Causes Infertility"

This is the one claim with real truth behind it, and it deserves an honest answer rather than a flat denial. Testosterone therapy works by supplying the hormone directly, which signals the brain to reduce its own production — including the signals that drive sperm production. For many men, this does reduce fertility while on therapy, and in some cases significantly.

The effect is usually reversible after stopping treatment, though the timeline varies by individual. If you're actively trying to conceive or planning to in the near future, this is exactly the kind of thing to discuss before starting — there are alternative approaches and monitoring strategies that can be used when fertility is a near-term priority.

Who Should Avoid TRT

Testosterone therapy isn't appropriate for everyone. Men with active prostate or breast cancer, uncontrolled heart failure, untreated severe sleep apnea, or a strong near-term desire to conceive need a different conversation before starting — which is exactly why a full history and lab review comes before any prescription, not after.

What Properly Monitored TRT Actually Looks Like

The risks above are largely tied to unmonitored or inappropriately dosed treatment. A responsible protocol includes a comprehensive lab panel before starting (see what blood tests you should get), a dose calibrated to bring you into a normal range rather than above it, and regular follow-up labs to track hematocrit, PSA, and hormone levels over time. That structure is what turns a genuinely useful treatment into a safe one.

If you're dealing with the symptoms of low testosterone — fatigue, low libido, mood changes, loss of muscle mass — learn more about how we evaluate and treat it, or see what happens at your first appointment.

This article is for educational purposes only and does not constitute medical advice. Please consult a qualified physician before starting any new treatment. — Justin Abbott, D.O., Abbott Health & Wellness, 45 North State Street, Salina, UT 84654.