Testosterone Therapy:

Evidence, Safety, and the Dangers of “Mill” Clinics

Testosterone replacement therapy (TRT) has seen a surge in popularity, fueled by growing awareness of low testosterone (“low T”) and a market saturated with clinics promising youth and vitality. Yet, the evidence about who actually benefits—and who is put at risk—remains nuanced. Recent peer-reviewed trials and leading clinical voices like Dr. Peter Attia offer clarity on the safety, efficacy, and potential pitfalls of testosterone therapy, especially regarding “mill-like” clinics and pellet formulations.

What Recent Research Shows About Testosterone Therapy

1. Safety and Cardiovascular Risk

The 2023 TRAVERSE trial, a large, randomized controlled study, is the most robust to date examining cardiovascular outcomes in men aged 45–80 with hypogonadism and cardiovascular risk factors. The study found that testosterone gel therapy did not increase the risk of major adverse cardiovascular events compared to placebo over a median follow-up of 22 months. This trial reassures both clinicians and patients that, when prescribed appropriately and monitored carefully, testosterone therapy is not associated with excess risk of heart attack, stroke, or cardiovascular death in this population (Lincoff et al., 2023).

Further meta-analyses reinforce these findings: when analyzing aggregate data from dozens of randomized trials, there is no significant increase in cardiovascular mortality or major events in hypogonadal men on TRT versus placebo (Hudson et al., 2022; Corona et al., 2024).

2. Prostate Health and Cancer Risk

Concerns about testosterone fueling prostate cancer have long influenced clinical caution. However, recent studies, including a large JAMA Network Open analysis of the TRAVERSE population, found no significant increase in prostate cancer, acute urinary retention, or need for prostate interventions among men on TRT compared to placebo (Bhasin et al., 2023). Attia and Schaeffer (2023) further explain that the “androgen hypothesis” of prostate cancer has not been strongly supported in recent years, with new data showing no meaningful increase in high-grade prostate cancer from physiologic testosterone replacement.

3. Efficacy and Who Benefits

Meta-analyses and recent expert reviews confirm that men with documented low testosterone and symptoms—such as low libido, reduced muscle mass, fatigue, or osteoporosis—are most likely to benefit from TRT (Grossmann et al., 2024; Xu et al., 2024). Improvements have been seen in sexual function, bone mineral density, lean body mass, and overall vitality (Xu et al., 2024; Grossmann et al., 2024). Importantly, these benefits are best realized when therapy is tailored and titrated to individual needs, under the supervision of a qualified clinician.

The Dangers of “Mill” Clinics and Pellet Therapy

Despite evidence-based protocols, many “low T” or “hormone optimization” clinics—often called “mills”—have emerged, offering quick prescriptions or long-acting pellets with minimal evaluation or follow-up. Dr. Peter Attia (2021, 2023) warns that this model exposes patients to unnecessary risks:

• Inadequate Assessment: Mill-like clinics may prescribe testosterone to men who do not meet strict diagnostic criteria, increasing risks without proven benefit.

• Pellet Therapy Risks: Pellets provide a large, non-adjustable dose of testosterone over months, making it impossible to titrate or pause therapy if side effects occur. This can lead to supraphysiologic levels, elevated hematocrit, and unpredictable fluctuations.

• Lack of Monitoring: Ongoing lab surveillance (hematocrit, PSA, cardiovascular markers) is critical for safety. Mills often skip this, putting patients at risk of undetected complications (Attia, 2023).

As Attia (2021, 2023) emphasizes, “testosterone therapy should not be viewed as a shortcut or anti-aging fix, but as a legitimate medical treatment for men with clear indications—requiring careful assessment, dosing, and follow-up.”

What Patients Should Know

• Seek experienced clinicians who will confirm low testosterone with labs and assess symptoms, not just prescribe based on age or fatigue alone.

• Ask about ongoing monitoring: Hematocrit, PSA, cardiovascular risk, and prostate health should be checked regularly.

• Be cautious of pellet implants and “quick fix” clinics that do not offer tailored care or dose adjustments.

• Understand that TRT is not for everyone: Most benefit is seen in men with proven deficiency and symptoms; unnecessary therapy may cause harm.

Conclusion

Testosterone therapy, when properly prescribed and monitored, is both safe and effective for men with true hypogonadism and symptoms. Major recent studies and expert reviews have debunked many fears about cardiovascular and prostate risk, but only when therapy is individualized—not delivered en masse through “mill” clinics or rigid pellet regimens. Patients should prioritize evidence-based care and regular monitoring, working with clinicians who follow the latest science, not fads.

References

Attia, P. (2021). AMA #28: Testosterone and Testosterone Replacement Therapy.https://peterattiamd.com/ama28/

Attia, P. (2023). The TRAVERSE Trial and Testosterone Replacement Therapy in Men.https://peterattiamd.com/traverse-trial-and-trt-in-men/

Attia, P., & Schaeffer, T. (2023). Testosterone, prostate cancer risk, and clinical decision-making.https://peterattiamd.com/tedschaeffer3/

Bhasin, S., Cunningham, G. R., Hayes, F. J., Matsumoto, A. M., Snyder, P. J., Swerdloff, R. S., ... & Lincoff, A. M. (2023). Prostate safety events during testosterone replacement therapy in men with hypogonadism. JAMA Network Open, 6(12), e2345657.https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2813293

Corona, G., Maseroli, E., Rastrelli, G., & Maggi, M. (2024). Cardiovascular outcomes of testosterone replacement therapy: updated systematic review and meta-analysis. Current Opinion in Endocrinology, Diabetes and Obesity, 31(1), 28–34.https://pubmed.ncbi.nlm.nih.gov/38553429/

Grossmann, M., Hoermann, R., & Zajac, J. D. (2024). Testosterone therapy in older men: clinical implications of recent randomized trials. European Journal of Endocrinology, 191(1), R22–R36.https://academic.oup.com/ejendo/article/191/1/R22/7698939

Hudson, J., Cruickshank, M., Srikusalanukul, W., & Wong, J. (2022). Adverse cardiovascular events and mortality in men during testosterone treatment: an individual patient data meta-analysis. The Lancet Healthy Longevity, 3(7), e381–e393.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9184259/

Lincoff, A. M., Costa, F., Wang, Z., et al. (2023). Cardiovascular safety of testosterone-replacement therapy. New England Journal of Medicine, 389(2), 107–117.https://www.nejm.org/doi/full/10.1056/NEJMoa2215025

Xu, L., Spitzer, M., DeRosa, A., & Fain, R. (2024). Effects of testosterone replacement therapy on sexual function and prostate parameters: systematic review and meta-analysis. Andrology, 12(1), 123–135.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10853420/

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