Frequent ejaculation has unexpected side effect, Oxford University scientists find

Joshua Nair
2026-03-27T16:02:28.565Z
News

Some of the things we've been told about reproduction may have been disproven by this new study

A new study from researchers at Oxford University has found that ejaculating more often than not can be a positive, contrary to popular belief.

As part of new research, which was published on Wednesday (25 March), the study looked at the effects of abstinence not only in humans, but in animals too.

The conversation around reproduction often centres around female biology and how it can be perceived as a 'ticking clock', according to Oxford scientists.

Essentially, women are born with most of their lifetime supply of eggs, meaning a woman's age is normally the same age as her eggs, with older women producing older eggs.

But for men, sperm is produced continuously from puberty onwards, with the reproductive cells able to be stored in the reproductive tract before ejaculation.

So while it is kept here, what actually happens to sperm?

Abstaining may not be the best thing for a man's sperm if he's looking to reproduce (Getty Stock Image)

Does abstinence affect sperm health?

It has long been believed that abstinence from ejaculation, even for just a few days, can increase sperm count but while this is true, there are other factors which determine fertility.

The study found that in men and other male animals, 'sperm stored during sexual abstinence actually 'ages' and deteriorates in quality'.

Male fertility does decline with age, with it remaining unclear if time spent by sperm in storage has an impact on this decline.

The scientists note that sexual activity, especially in young people, is declining as the global trend of delayed parenthood may cause global fertility declines to go on.

They collected semen data from 115 published studies covering almost 55,000 men, finding that when men abstained from ejaculation, the health of their sperm dropped massively, was sperm motility and viability decreased.

Even sperm DNA became more damaged.

Abstaining before trying to conceive may lower your chances (Getty Stock Image)

Causes of sperm damage

Apparently, there are two likely causes, as they explain that the first is something called 'oxidative stress'.

It is 'a form of biological 'rust' that accumulates in sperm and can physically damage them'.

They go on: "The second is energy depletion. Unlike most cells, sperm are highly active and have only a limited capacity to replenish their energy reserves.

"When stored for extended periods, they simply run out of fuel."

According to the World Health Organization, you should avoid ejaculating two to seven days before providing a sperm sample for analysis, or even before fertility treatments such as IVF.

But the boffins at Oxford claim that shorter periods may actually result in better in sperm quality, which they say backs up a recent claim that ejaculating within 48 hours of providing a sample can improve IVF treatment outcomes.

They add: "We know that in primates, frequent ejaculation from masturbation improves the quality of ejaculate. Combined with our results, this suggests that male masturbation may have an adaptive benefit: it flushes out damaged, stored sperm."

Sperm can also deteriorate inside women after mating, with human sperm only remaining alive inside a woman for several days, while other animals such as bees and female ants can store sperm for months or years after eggs are fertilised.

Similar results were found in other species (Getty Stock Image)

Comparison to animals

Data from 56 studies across 30 animal species, such as birds, bees, reptiles and mammals, showed that sperm quality declined in storage once again.

Scientists claimed that this is not just caused by damaged DNA, as it may be due to the fact that stored sperm has a different fene expression profile, compared to freshly produced sperm.

This includes sperm stored in either the father or mother.

The cells were found to deteriorate at a slower rate in females compared to males, which could be due to certain female species having specialised organs that can 'secrete antioxidants'.

They conclude: "Many fertility problems are driven by factors outside our control, such as environmental toxins, stress and genetics."

The duration of sperm storage though, is something which can be controlled, as freshly ejaculated sperm for fertilisation may boost fertility chances due to an overall improved sperm quality.