NOTICE: This article is intended for readers aged 16 and over.
Arnaud Pontin (Photo : Pixabay)
A Harvard Study at the Heart of a Catchy Headline
In a recent article published in a scientific journal and widely shared on the publication’s Facebook page, an eye-catching study title caught attention: “21 ejaculations per month, the new goal for men? What Harvard’s 2025 prostate cancer study really reveals.” This striking headline quickly drew interest but deserves to be examined in light of the actual scientific data.
Ejaculation and Prostate Health: What We Already Know
For a long time, ejaculation has been recognized as a physiological mechanism allowing the expulsion of semen and various liquid compounds. Over the years, some hypotheses have also circulated suggesting that this process might help the prostate eliminate unhealthy cells, and in some cases, even cancerous cells. These claims, often relayed without nuance, raise a central question: what does science really say about the link between ejaculation frequency and prostate cancer?
A Media Headline, But Not a 2025 Study
Contrary to what the widely circulated headline implies, no study published in 2025 officially bears this title. Several scientific works indeed establish an association between ejaculation frequency and prostate cancer risk, some led by researchers affiliated with Harvard, but the phrase “21 ejaculations per month” is primarily a media interpretation of earlier research findings.
The Health Professionals Follow-up Study: A Solid Scientific Foundation
The most credible data come from a large epidemiological study conducted within the Health Professionals Follow-up Study, a cohort of health professionals monitored over several years. This research program, involving contributions from scientists at the Harvard T.H. Chan School of Public Health, represents one of the most robust databases on the links between health behaviors and chronic diseases in men.
Findings Published in the Journal of the American Medical Association
Published in the Journal of the American Medical Association (JAMA), the landmark study examined the relationship between participants’ self-reported ejaculation frequency and the subsequent risk of developing prostate cancer. Researchers followed thousands of men over many years, taking into account their ejaculation frequency at various adult ages.
The results show that a high frequency, defined as 21 ejaculations or more per month, is associated with a reduced overall risk of prostate cancer compared to a lower frequency of 4 to 7 ejaculations monthly. This association is particularly notable among men aged 40 to 49, especially when considering the most recent period before analysis, according to JAMA Network data.
Statistical Association, Not Proof of Causation
The study’s authors remain cautious. The results do not establish a direct causal link: ejaculating more often does not automatically guarantee protection against prostate cancer. Rather, it is a statistically significant association observed in certain adjusted analyses, as also emphasized by the American Academy of Family Physicians (AAFP).
Why Media Figures Vary
Risk reduction percentages reported in the media vary significantly, ranging from about 20% to 31% depending on the source. These differences do not reflect the publication of a new 2025 study but stem from different interpretations of the same data or comparative meta-analyses, sometimes simplified in mainstream media outlets such as Le Tribunal du Net.
The Scientific Reference to Keep in Mind
For readers wishing to consult the original scientific source or find the reference on PubMed, the foundational study remains the one published in JAMA Network titled: “Ejaculation Frequency and Subsequent Risk of Prostate Cancer.”
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