Key takeaways

Low testosterone is diagnosed when both your labs and your symptoms agree — not by a single number in isolation. The decision to start testosterone replacement therapy (TRT) deserves more than a seven-minute visit. Done well, it includes a real baseline lab panel, a monitoring schedule that catches the things that actually matter (hematocrit, estradiol, lipids), and an honest conversation about fertility and what happens if you decide to stop. Here is what physician-led TRT actually looks like.

You have had the lab results back: total testosterone at 280 ng/dL. Your doctor either told you that is borderline and to come back in a year, or offered a prescription before you had finished asking your questions. Neither feels right.

Testosterone therapy is real medicine, not a lifestyle decision. Done thoughtfully, it can be transformative for men with genuine deficiency. Done casually — with a single lab value, no monitoring, and no plan for what happens next — it creates problems that take longer to clean up than the symptoms it was supposed to fix.

Here is what the current evidence actually shows, what your labs mean beyond the total testosterone number, and what to look for in any program you consider.

What 'Low Testosterone' Actually Means

The American Urological Association defines low testosterone as a total testosterone level below 300 ng/dL, confirmed on at least two early-morning fasting blood tests, accompanied by symptoms consistent with deficiency. Both criteria need to be present.

That second part is what gets skipped. A single value in the mid-200s on a Tuesday afternoon, drawn after a stressful week and a poor night of sleep, is not a diagnosis. Testosterone has a real circadian rhythm — values are highest in the morning and decline through the day. It is also responsive to sleep, alcohol, weight, illness, and recent training. Two fasting morning draws on different days is the standard for a reason.

Free Testosterone, SHBG, and Why Total Is Not the Whole Story

Total testosterone measures everything circulating in your blood — but most of it is bound to sex hormone binding globulin (SHBG) and albumin. Only 1–3% is biologically active 'free' testosterone. Two men with identical total testosterone can have meaningfully different free testosterone depending on their SHBG level. If your SHBG is elevated, your total may look reasonable while your free is genuinely low — and your symptoms will reflect the free level, not the total.

Any TRT workup that does not include SHBG and a calculated or measured free testosterone is incomplete.

Before You Reach for a Prescription

Some men with low-borderline testosterone respond well to lifestyle changes alone. The honest answer is that most men over 40 do not — but it is worth knowing what is achievable before committing to therapy.

Three levers reliably move testosterone in the right direction in the published literature:

Sleep. Restricting sleep to 5 hours for a single week lowers daytime testosterone in young men by 10–15% (Leproult & Van Cauter, JAMA 2011). Untreated obstructive sleep apnea is one of the most reversible causes of low T — and it should be evaluated and managed before or alongside TRT, since testosterone can exacerbate untreated OSA.

Body composition. Excess adipose tissue increases aromatase activity, converting testosterone to estradiol. Significant weight loss meaningfully improves testosterone in men with overweight and obesity.

Resistance training. Heavy compound lifting two to three times weekly supports endogenous testosterone production over the long term — and has the further benefit of preserving the muscle mass TRT also helps preserve.

Supplements are a long way down the list. Zinc and vitamin D help if you are deficient. Most of what is marketed on testosterone-boosting supplement bottles does not survive a critical reading of the trials.

The TRT Options and What They Actually Differ On

Injectable Testosterone (Cypionate and Enanthate)

The most commonly prescribed approach. Subcutaneous or intramuscular, typically twice weekly. Pros: dose is fully adjustable, blood levels are predictable, cost is low. Cons: requires self-injection, and dose timing matters for keeping levels stable rather than peaks-and-troughs.

Gels and Creams

Daily transdermal application. Pros: no needles. Cons: absorption varies meaningfully person to person, and transfer to a partner or child through skin contact is a real consideration, particularly with gel preparations.

Pellets

Surgically implanted, last 3–4 months, no daily or weekly dosing required. The drawback that matters: once they are in, the dose is fixed. If levels run too high or too low, the response is either another procedure or waiting for the pellets to wear off. The AUA TRT Guideline lists pellets as one delivery option; most TRT-focused physicians do not use them first-line because of this inflexibility.

Oral Testosterone (Newer Formulations)

Approved oral testosterone undecanoate formulations are newer. They avoid injections and gel transfer. The tradeoff is twice-daily dosing with food and a more limited body of long-term data than injectable testosterone.

What Real Monitoring Looks Like

The single most common preventable complication of TRT is rising hematocrit — too many red blood cells, which thickens the blood and creates clotting risk. Most TRT-focused physicians use a hematocrit threshold of around 54% to trigger dose reduction, increased phlebotomy, or other management steps. It is fully manageable with periodic labs, dose adjustment, or therapeutic phlebotomy when needed. It is essentially never managed if no one is checking.

A reasonable TRT monitoring plan looks like this:

Baseline: total and free testosterone, SHBG, estradiol (sensitive assay), CBC with hematocrit, PSA if age-appropriate, lipid panel, fasting glucose and HbA1c, comprehensive metabolic panel, and blood pressure (now formally part of the testosterone monitoring conversation per FDA's 2025 labeling).

3–6 months: repeat testosterone, estradiol, hematocrit, PSA. Adjust dose based on results and symptoms.

Annually thereafter: full panel including PSA, with the cadence individualized based on age, family history, and prior values.

An aromatase inhibitor such as anastrozole — the medication class that lowers estradiol — is not a default add-on. Many men do well without one. It should be used only when there is a clinical reason — not as part of a stack handed out by default.

Fertility and Stopping TRT — The Honest Section

Most men's biggest unspoken question about TRT is what happens if they decide to stop. The answer is real and deserves a real conversation.

Exogenous testosterone suppresses the body's natural signals to produce its own testosterone, and spermatogenesis (sperm production) typically declines. For men who want to preserve fertility while on TRT, co-administering hCG or gonadorelin can support testicular function during therapy. This should be discussed before starting, not after the decision is already made.

If you stop TRT, most men's natural production recovers within 3–6 months. Some men recover more slowly. A small subset experience a meaningful low period during the transition off therapy — including mood changes and persistent low energy — which is worth knowing in advance so it can be planned for, not encountered as a surprise.

Is TRT Safe for Your Heart? What the TRAVERSE Trial Established

The TRAVERSE trial, published in the New England Journal of Medicine in 2023, was the largest randomized placebo-controlled trial of testosterone therapy in men with hypogonadism at elevated cardiovascular risk. The primary cardiovascular endpoint showed no significant increase in major adverse cardiac events with testosterone compared with placebo.

Where signals did appear: somewhat higher rates of atrial fibrillation, acute kidney injury, and pulmonary embolism in the testosterone group, all manageable in ongoing care.

In February 2025, the FDA removed the cardiovascular boxed-warning language from testosterone product labels, reflecting the TRAVERSE results. The same action added a new class-wide warning about increased blood pressure, based on required post-market ambulatory blood pressure monitoring studies. Both changes reflect the more complete safety picture that has emerged since 2015.

In December 2025, an FDA expert panel held public discussions on whether to expand indications, reconsider the limitation-of-use language for age-related hypogonadism, and revisit other warnings. Those discussions are advisory and the FDA has not yet acted on them.

The bigger picture: when TRT is prescribed for men who actually have low testosterone and is monitored appropriately, the cardiovascular profile is better than the 2010s reputation suggested — with blood pressure now formally part of the monitoring conversation.

How Leader Health Approaches This

At Leader Health, every TRT workup starts with a full hormone panel — not just total testosterone — and a real conversation about your goals, your monitoring preferences, and what happens if you decide therapy is no longer right for you. A physician reviews your labs and your history before any prescription is considered.

If you are looking for a TRT program that treats you like an adult making a long-term decision about your own health, this is the one to compare against.

References

1. Lincoff AM, et al. Cardiovascular Safety of Testosterone-Replacement Therapy. N Engl J Med. 2023;389(2):107-117. PMID: 37326322.

2. FDA. FDA Issues Class-Wide Labeling Changes for Testosterone Products: Cardiovascular Boxed Warning Removed; Blood Pressure Warning Added. February 28, 2025. fda.gov/drugs/drug-alerts-and-statements/fda-issues-class-wide-labeling-changes-testosterone-products.

3. Anderer S. FDA Updates Testosterone Labeling for Blood Pressure and Cardiovascular Risks. JAMA. 2025;333(17):1478.

4. Leproult R, Van Cauter E. Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men. JAMA. 2011;305(21):2173-4.

5. Mulhall JP, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline. American Urological Association.

6. Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744.

7. Corona G, et al. European Expert Panel Position Statement on Testosterone Therapy (TRAVERSE follow-up). Andrology. 2026. PMID: 40372318.

8. FDA. Expert Panel on Testosterone Replacement Therapy for Men. December 10, 2025. fda.gov/patients/fda-expert-panels/fda-expert-panel-testosterone-replacement-therapy-men-12102025.

9. Attia P. AMA #28: Testosterone Replacement Therapy. The Peter Attia Drive Podcast. peterattiamd.com/ama28/