How Often Should Men Have Sex? Harvard Study Links 21 Times a Month to Lower Prostate Cancer Risk

Introduction: The Growing Burden of Prostate Cancer

Prostate cancer (PCa) is one of the most commonly diagnosed cancers in men worldwide, accounting for approximately 15% of all new male cancer cases. As the global burden of prostate cancer continues to increase, identifying effective preventive measures has become a pressing challenge. While diet and physical activity have demonstrated some promise in secondary prevention, there remain no clear evidence-based guidelines specifically advising healthy adult men on how to reduce their risk of developing prostate cancer.

Among the few known risk factors for PCa—such as age, race, family history, and inherited genetic variations—none are modifiable. Therefore, attention has turned to potential lifestyle factors that men can change. One such factor is sexual activity, specifically ejaculation frequency, which has been hypothesized to influence prostate cancer risk through a variety of biological mechanisms.