Testosterone and Prostate Health: What the Evidence Actually Shows

Written by Adam Maggio | Medically reviewed by Dr. Mitchell Ross, MD, ABAARM

The historical fear that testosterone causes prostate cancer has been largely refuted. The saturation model suggests prostate tissue is maximally stimulated at testosterone levels well below the normal range. TRT does not increase prostate cancer risk in men without pre-existing cancer. PSA monitoring is still recommended.

The Historical Fear and Its Origins

For decades, the relationship between testosterone and prostate health was dominated by a simple but ultimately incorrect model: testosterone feeds prostate cancer growth, therefore testosterone replacement is dangerous. This belief stemmed from observations in the 1940s that castration (which dramatically reduces testosterone) caused regression of metastatic prostate cancer. The logical but flawed extrapolation was that higher testosterone must cause more aggressive prostate cancer growth.

The Saturation Model

The saturation model, developed by Abraham Morgentaler and colleagues, provides a more accurate framework for understanding the testosterone-prostate relationship. The model proposes that prostate tissue has a finite capacity to respond to testosterone — once androgen receptors are saturated (which occurs at relatively low testosterone levels, around 200–250 ng/dL), additional testosterone produces no further stimulation of prostate growth. This explains why: men with very low testosterone can have prostate cancer, TRT does not increase PSA levels in most men, and men with higher testosterone do not have higher rates of prostate cancer.

Evidence from Clinical Studies

Multiple large observational studies and meta-analyses have failed to find an association between higher testosterone levels and increased prostate cancer risk. The TRAVERSE trial — the largest RCT of TRT — found no significant difference in prostate cancer incidence between testosterone-treated men and placebo-treated men over a median follow-up of 33 months. Importantly, TRT has been used successfully in carefully selected men with a history of treated prostate cancer, with no evidence of cancer recurrence in multiple case series.

PSA Monitoring on TRT

Despite the reassuring evidence on prostate cancer risk, PSA monitoring remains an important part of TRT management. PSA may increase modestly when testosterone is restored to normal levels (reflecting normalization of prostate function rather than cancer stimulation). A PSA increase of more than 1.4 ng/mL in the first year of TRT, or any PSA above 4 ng/mL, warrants urological evaluation.

Benign Prostatic Hyperplasia (BPH)

TRT may worsen lower urinary tract symptoms in men with pre-existing BPH. Men with significant BPH symptoms should have these addressed before starting TRT, and should be monitored for symptom changes after initiation.