Why Do Women Live Longer Than Men? The Science Explained

If you are a woman, the odds are in your favor when it comes to longevity. On a global average, women tend to outlive their male counterparts by approximately five years.

While the definitive reasons behind this female longevity are not fully understood, scientists have identified several key factors that contribute to this persistent gap. These findings also shed light on why, in other species such as certain birds, it is actually the males that possess the evolutionary advantage in lifespan.

Dying too young

“In almost every country, women live longer than men,” says Prof. Sarah Harper, Director of the Oxford Institute of Population Ageing in the UK. However, she notes that the disparity varies significantly from one nation to another.

According to research data from Our World in Data, the gap is wide in countries like Russia, Ukraine, and Vietnam, where women live a decade or more longer than men. In contrast, the difference is minimal in places like Nigeria. Scientists attribute much of this variation to distinct social and behavioral differences.

In Russia, for instance, Prof. Harper points to smoking and alcohol consumption as major drivers of early mortality, habits that remain more prevalent among men. On a global scale, men are also statistically more likely to engage in risk-taking behaviors that truncate their lives.

“Their diets are generally less healthy,” Harper observes. She also points out that men tend to visit doctors less frequently, although married men often benefit from partners who encourage them to seek medical care. Furthermore, in many societies, men are more frequently employed in high-risk occupations, and traditional notions of masculinity are often tied to higher risk tolerance.

“Male mortality rates are significantly higher due to traffic accidents, violence, homicide, and suicide,” she adds. Yet, this picture is not fixed. In the United Kingdom, for example, anti-smoking campaigns in the 1960s and 1970s led to a marked decline in premature male deaths, causing the gender gap to shrink drastically. Even so, experts believe that some biological differences will always persist.

Estrogen vs. Testosterone

One of the primary biological factors is hormones. “Estrogen does a great deal to protect women,” explains Prof. Consuelo Borrás, a physiologist specializing in aging at the University of Valencia, Spain. This protection includes regulating cholesterol levels and the immune system, while also helping to prevent urinary tract infections and maintaining brain and bone health.

Estrogen functions as an antioxidant, combating harmful free radicals—unstable molecules that accumulate in cells and accelerate the aging process. “Many studies show that the loss of estrogen protection during menopause affects various body functions,” Borrás notes, pointing to osteoporosis as a clear example of this shift. She adds that when hormone replacement therapy is administered to the right candidates early in menopause, many of these vital functions can be supported.

Conversely, the primary male sex hormone, testosterone, is linked to higher risk-taking tendencies. Borrás suspects it may also have detrimental effects on the body, though the exact mechanisms remain under investigation. A 2012 study of historical Korean eunuchs—who, having been castrated, produced no testosterone—found they lived 14 to 19 years longer than non-castrated men. While such data is limited and cannot be replicated today, similar evidence in animal studies suggests that males often live longer following castration.

Clues from evolution

To better understand these patterns, researchers have looked beyond humans. While many mammals exhibit the same female-led longevity, the opposite is true for birds. Dr. Johanna Staerk, a researcher at the Max Planck Institute for Evolutionary Anthropology, explains that the answer may lie in sex chromosomes.

“In mammals, females have two X chromosomes, while males have one X and one Y,” Staerk notes. One theory suggests that having two copies of the X chromosome provides a survival advantage because if a mutation occurs on one copy, the other can compensate. Males, with only one X chromosome, lack this safety net.

In birds, the system is reversed: males have two identical chromosomes (ZZ), while females have one Z and one W, providing a potential explanation for why male birds often live longer. However, Staerk’s 2025 research indicates that social structures also play a role. “We found that in monogamous species, there is no striking sex difference,” she says. “In contrast, in non-monogamous species like gorillas or lions—where males compete intensely for multiple females—the gap is much larger.”

This suggests that males have evolved to prioritize energy-intensive tasks, such as growing large or developing elaborate features for mating, often at the expense of longevity. Meanwhile, for species where females care for offspring, it is evolutionarily advantageous for the mother to live long enough to raise her young to adulthood.

Living longer and healthier

Despite the longevity gap, it is not all positive for women. Research indicates that while they live longer, they are more prone to non-fatal health conditions, such as lower back pain, depression, and headaches. “Women tend to have a stronger immune response, but that can also trigger inflammatory diseases,” says Harper. “Additionally, their musculoskeletal systems are slightly less robust.”

Ultimately, as Prof. Borrás concludes, “Biology makes men more vulnerable to death, while biology makes women more vulnerable to disability.” However, the experts emphasize that biology is not destiny. Environmental factors and lifestyle choices—such as diet, exercise, sleep quality, and stress management—are crucial for everyone, not just for extending life, but for ensuring that those added years are lived in good health.