Women almost everywhere in the world live longer than men. On average – by about five years. And in some countries, the difference is even greater, according to statistics. Scientists have long been trying to understand why this is the case, writes BBC.
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Men Take More Risks
"In almost all countries of the world, women live longer than men," confirms Professor Sarah Harper, Director of the Oxford Institute of Population Ageing in the UK.
However, the extent of this difference varies greatly by country.
For example, in Ukraine and Vietnam, women live on average ten or more years longer than men.
However, in Nigeria, this gap is almost imperceptible.
Scientists believe that this is partly explained by lifestyle and social habits. According to Harper, in some countries "smoking and alcohol play a large role" – men consume them much more frequently.
Globally, men are more prone to behaviors that shorten life expectancy.
"Their diet is usually less healthy," notes Harper.
Men also visit doctors less often. Although, she adds, "married men have an advantage... because their partner makes them monitor their health."
In many countries, men more often work in dangerous professions. Moreover, notions of "true masculinity" are often associated with a willingness to take risks.
"Among men, there is significantly higher mortality from road accidents, violence, homicides, and suicides," emphasizes Harper.
However, the situation can change.
For example, in Britain, anti-smoking campaigns in the 1960s-70s significantly reduced the level of premature mortality among men.
Estrogen vs. Testosterone
There are also purely biological reasons.
The hormone estrogen plays a large role. It helps protect the heart, bones, brain, and immune system.
"Estrogen supports the female body very well. Therefore, before menopause, women often have a certain biological advantage," explains Professor Consuelo Borrás, a physiologist and aging researcher from the University of Valencia in Spain.
According to her, estrogen acts as an antioxidant – neutralizing harmful particles, so-called free radicals, which accumulate in cells and accelerate aging.
In contrast, testosterone – the main male sex hormone – is associated with a greater propensity for risk.
Borrás suggests that it may also have a negative impact within the body, although these mechanisms are not yet sufficiently studied.
An interesting example was provided by a 2012 study: historical Korean eunuchs, who did not produce testosterone after castration, lived 14-19 years longer than other men.
However, such data have their limitations – for understandable reasons, similar studies cannot be replicated today. At the same time, a trend is also observed in some animals: castrated males live longer.
But hormones are only part of the longevity puzzle.
"There are many factors. We only know a part of them. It is an extremely complex process," concludes Borrás.
What Evolution Says About This
To better understand the reasons, scientists study not only humans.
We are far from the only species where females live longer. This is characteristic of many mammals: from lions and sheep to orcas and mice.
However, in birds, the situation is the opposite: there, the advantage is usually on the side of males.
One possible reason is the peculiarities of sex chromosomes.
"In mammals, females have two X-chromosomes, while males have one X and one Y," explains Johanna Stärk, a researcher from the Max Planck Institute for Evolutionary Anthropology in Germany.
According to one theory, the presence of two X-chromosomes creates a kind of "reserve of resilience" for females.
"If a mutation occurs in one copy, there is a second one that can compensate for the problem," says Stärk.
"And males have only one X-chromosome, so mutations can be much more dangerous."
In birds, it's the opposite: males have two identical Z-chromosomes, while females have a ZW set.
"This might explain why in mammals, females live longer, and in birds, males do," Stärk suggests.
However, her 2025 study suggests that everything is much more complex.
"We found that in monogamous species... there is almost no noticeable difference between the sexes," she says. "And in non-monogamous species, such as gorillas or lions, where males compete for several mates, the differences are much stronger."
In her opinion, in such species, evolution forced males to expend enormous resources on developing large bodies, powerful horns, or other features that attract "females" – and this came at the expense of longevity.
In contrast, females could have evolved according to a different scenario.
There is a hypothesis that in species where females care for offspring, "especially in species like humans or great apes, it is advantageous for mothers to live longer to have time to raise their young," says Stärk.
Longer Isn't Always Better
However, as studies show, female longevity also has a downside.
Although women live longer, they more often face chronic, though not fatal, diseases: lower back pain, depression, and migraines.
"Women usually have stronger immune responses, and this increases the risk of inflammatory and autoimmune diseases," explains Professor Harper.
In addition, she adds, "women have less robust muscular and skeletal systems."
Therefore, a paradox arises: male biology makes them more vulnerable to death, while female biology makes them more vulnerable to disability.
But despite everything, experts emphasize: biology is not a sentence.
"Life expectancy is also greatly influenced by environment and lifestyle," says aging researcher Consuelo Borrás.
Both men and women should pay attention to nutrition, physical activity, sleep, and stress levels – not only "to live longer, but also to live better."
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