A major study involving almost 32,000 men has identified an intriguing association between ejaculation frequency and the likelihood of developing prostate cancer.
Researchers examining men's sexual habits over nearly two decades found that those who reported ejaculating more frequently were less likely to receive a prostate cancer diagnosis.
The findings, published in the medical journal European Urology in 2016, have continued to attract attention because of the potential connection between sexual activity and prostate health.
However, experts caution that the study does not establish that ejaculation directly prevents prostate cancer.
How many times a month did the study identify?
The figure highlighted by researchers was 21 or more ejaculations per month.
Men who reported ejaculating at least 21 times monthly had a significantly lower risk of being diagnosed with prostate cancer compared with men who reported ejaculating between four and seven times per month.
Researchers found an approximately 20% lower relative risk in the higher-frequency group, although the precise association varied depending on the age period being examined.
That works out at roughly five ejaculations per week.
Importantly, the researchers were not prescribing 21 ejaculations as a medically proven target. The figure represented a frequency category used in their analysis.
The findings also do not mean that men who ejaculate less frequently will develop prostate cancer, or that ejaculating more often guarantees protection.
What did the Harvard researchers discover?
The research was conducted using data from the Health Professionals Follow-up Study, a long-running American investigation into men's health.
Scientists analysed information from 31,925 participants who had reported their ejaculation habits at different stages of adulthood.
Participants were followed over approximately 18 years, allowing researchers to compare their reported habits with subsequent prostate cancer diagnoses.
During the follow-up period, 3,839 men were diagnosed with prostate cancer.
Of those cases, 384 were classified as lethal, meaning the cancer had spread to distant sites or resulted in death.
The analysis found that men reporting more frequent ejaculation were generally less likely to develop prostate cancer than those reporting lower frequencies.
The association was particularly apparent for lower-risk forms of the disease.
However, the study did not establish the same clear protective association for aggressive or lethal prostate cancers.
Why might ejaculation be linked to prostate health?
Researchers have explored several possible explanations for the association, although none has been definitively established.
One theory is that ejaculation may influence the composition or turnover of fluid produced by the prostate gland.
Another possibility is that ejaculation frequency reflects broader differences in health, hormones or lifestyle that may also influence cancer risk.
Scientists have also investigated potential links between prostate inflammation and cancer development.
However, these explanations remain hypotheses rather than proven mechanisms.
The study's authors concluded that their findings provided additional evidence of a possible beneficial association between ejaculation frequency and prostate cancer risk.
They did not establish a direct biological cause.
Does masturbation count?
Yes. The study examined ejaculation frequency rather than restricting its analysis to one particular form of sexual activity.
Reported ejaculation frequency included sexual intercourse, masturbation and nocturnal emissions.
That means the research was not specifically about masturbation, despite some headlines focusing on it.
Instead, the researchers were interested in how often ejaculation occurred overall.
It is also important to recognise that the findings were based on participants' self-reported information, which can be affected by memory and reporting inaccuracies.
Can ejaculating more often actually prevent prostate cancer?
Although the findings are interesting, the research cannot prove that ejaculating more frequently prevents the disease.
The study was observational, meaning researchers examined associations between participants' reported behaviour and their subsequent health outcomes.
They did not randomly assign men to different ejaculation frequencies or control every possible factor that might influence prostate cancer risk.
Consequently, other characteristics could help explain the relationship.
There is currently no established medical recommendation requiring men to ejaculate a particular number of times per month to prevent prostate cancer.
Men should not feel pressured to meet a numerical target or assume that sexual activity can replace established healthcare advice.
How common is prostate cancer?
Prostate cancer is one of the most frequently diagnosed cancers among men.
According to the American Cancer Society, approximately one in eight men in the United States will be diagnosed with prostate cancer during their lifetime.
The likelihood of developing the disease increases with age, and most cases are diagnosed in older adults.
Family history and inherited genetic factors can also influence a person's risk.
In the United States, Black men have a higher incidence of prostate cancer than many other population groups, although the reasons involve a complex combination of factors.
Many prostate cancers grow slowly and may never cause serious health problems, while others can be aggressive and require prompt treatment.
What are the symptoms of prostate cancer?
Early prostate cancer frequently causes no noticeable symptoms.
When symptoms do occur, they can include:
These symptoms can also result from conditions unrelated to cancer, including benign prostate enlargement or urinary infections.
Anyone experiencing persistent or unexplained symptoms should seek medical advice rather than attempting to diagnose the cause themselves.
What can men do to look after their prostate health?
While researchers continue investigating possible links between sexual activity and prostate cancer, there are other important considerations for men's health.
Maintaining a healthy weight, exercising regularly and following a balanced diet can support overall wellbeing.
Men should also be aware of their family medical history, particularly if close relatives have experienced prostate cancer.
Discussions about prostate-specific antigen (PSA) testing should take account of age, individual risk factors and the potential benefits and limitations of screening.
PSA testing can help identify possible prostate problems, but it can also lead to false alarms and the detection of cancers that would never have caused harm.
For this reason, screening decisions are generally best made through an informed discussion with a healthcare professional.
What does the study mean for men?
The Harvard research offers an interesting insight into the possible relationship between ejaculation frequency and prostate cancer risk.
Its headline finding was that men reporting at least 21 ejaculations per month had a lower observed incidence of prostate cancer than those reporting considerably fewer.
However, the results should be interpreted cautiously.
The research identified a statistical association, not a guaranteed method of preventing cancer.
Further studies are needed to understand whether ejaculation itself plays a protective role or whether other biological and lifestyle factors explain the relationship.
For now, the findings provide another area for researchers to investigate, rather than a specific medical instruction for men to follow.
Sources: Rider et al., European Urology (2016), "Ejaculation Frequency and Risk of Prostate Cancer: Updated Results with an Additional Decade of Follow-up"; American Cancer Society.
