The safety of testosterone replacement therapy has been debated and studied for decades. The evidence has evolved significantly, and the current picture is considerably more favorable than the concerns that circulated in the early 2000s. Here is what the evidence actually shows.
Cardiovascular Safety
Earlier observational studies raised concerns about cardiovascular risk with TRT. The TRAVERSE trial, published in 2023, was the largest randomized controlled trial of testosterone therapy and cardiovascular outcomes ever conducted. It found no increase in major adverse cardiovascular events in men on TRT compared to placebo. Men with hypogonadism who restore testosterone to physiological levels show improvements in endothelial function, insulin sensitivity, and body composition that are net cardiovascular benefits.
Prostate Health
The saturation model, developed by Dr. Abraham Morgentaler at Harvard, explains why TRT does not promote prostate cancer growth. Prostate androgen receptors become saturated at relatively low testosterone levels. Above that threshold, increasing testosterone does not increase prostate cancer risk. Decades of prospective data support this. Men on TRT are monitored with PSA to detect pre-existing prostate cancer, but TRT does not cause new cancers to form.
Fertility
Exogenous testosterone suppresses sperm production by reducing LH and FSH. This is reversible for most men after discontinuation, but recovery takes months. Men who wish to preserve fertility should consider alternatives to exogenous testosterone including enclomiphene, clomiphene, or gonadorelin protocols that stimulate natural production rather than replacing it.
Hematocrit
TRT increases red blood cell production, which raises hematocrit. Elevated hematocrit above 52 to 54% increases blood viscosity and thromboembolic risk. AI Matrix Health monitors hematocrit regularly and adjusts protocols to keep it in a safe range. Therapeutic phlebotomy is an option when needed. Available in all 50 states.