Can too much DHT make your prostate grow?
DHT demonstrably stimulates prostate growth, and medicines that block DHT reduce symptoms and lower the risk of complications. If you are troubled by urinary problems or an enlarged prostate, this is something worth discussing with your doctor.
DHT is the substance that drives the prostate from the very beginning. During development in the womb, DHT, formed from testosterone by the enzyme 5-alpha-reductase, triggers the formation of the prostate. In adult men, DHT continues to stimulate the growth of prostate tissue and plays a central role in benign prostate enlargement.
Strong evidence that this is a genuine cause-and-effect relationship comes from the opposite direction: medicines that block the production of DHT demonstrably slow prostate growth. Finasteride, which suppresses DHT production, reduces urinary symptoms after more than a year of use and lowers the risk of serious complications such as suddenly being unable to urinate or needing surgery. Dutasteride, which lowers DHT even more strongly (by more than 93%), also showed less prostate cancer in a two-year study in men with prostate enlargement. Whether that truly reflects cancer prevention or simply a change in how cancer is detected has not yet been fully resolved.
DHT is not the whole story, however. Being overweight, having high blood sugar, high blood pressure, and blood fat problems together all worsen prostate enlargement through their own routes, alongside the hormonal effect. Prostate enlargement is now also seen as a metabolic condition, not purely a hormone issue.
Anyone using finasteride or dutasteride should know that side effects are real: erection problems, reduced sex drive, and ejaculation disorders can occur with finasteride. And abruptly stopping dutasteride led in animal studies to strong regrowth of the prostate, most likely because prostate cells temporarily become extra sensitive to the hormone. If you want to come off this medicine, discuss with your doctor how best to do that.
The evidence that DHT drives prostate growth rests on several pillars: a case description and review articles on the biology, animal studies with elevated hormone levels, and studies in people using medicines that block DHT. The combination of that biological line of evidence with clinical findings from DHT-blocking medicines makes the link causally strong. The animal studies (in mice and rats) support the mechanism but cannot be translated directly to people. The evidence on the rebound effect after stopping dutasteride comes only from rat studies.