Study reveals men's brains shrink faster than women with age, shares what it means for Alzheimer's risk

Women are more likely to get Alzheimer's, but brain volume stays stable. Find out more about this contradiction and what it means.

With age, the risks of neurodegenerative disorders like Alzheimer's disease rise. As one grows older, the brain's volume also shrinks in size, losing both grey and white matter over time. A study published in PNAS on October 13, 2025, revealed that the brain's shrinking pace differs by sex, actually. Men's brains shrink faster than women's. So if there's a correlation between brain shrinkage and neurodegenerative disease, what does it say about women's increased vulnerability to Alzheimer's disease?

What did the study find?

The forgetfulness of dementia is significant, affecting daily life functioning. (Shutterstock)

The study attempted to understand whether the brain tissue, grey and white matter, shrinks faster in men or women with age. So, according to the researchers, men's brains with age become smaller in volume, particularly the cortex, shrinking more. However, women's brains lose volume in certain selective areas, and more or less the cortex's thickness remains stable. Cortex is associated with important cognitive skills like thinking, memory, and decision-making.

Although there's no significant difference between men and women in regards to the shrinkage of the hippocampus, the brain area associated with memory, at least until old age. Women showed a decline in this area only later in life. But it doesn't necessarily mean it's because of a higher risk of neurodegenerative disorders. Instead, it demonstrates that women may live longer, hence the decline appears later because women reach older age more often than men.

What does it mean?

The interesting contradiction is sure to leave people scratching their heads. So, people with Alzheimer's showcase a shrunken brain. And women are more vulnerable to Alzheimer's. But here's the catch: based on the findings, it implies that brain shrinkage doesn't always indicate disease; it may be a part of the natural ageing process. Still, there needs to be more research to draw a complete picture of why women are likely to have a higher Alzheimer's risk.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.