Men’s Brains Shrink Faster Than Women’s: Insights Into Alzheimer’s Risk

A recent study reveals that men's brains shrink at a faster rate than women's as they age, raising questions about Alzheimer's disease risk. While neurodegenerative disorders like Alzheimer's become more prevalent with age, the study published in PNAS on October 13, 2025, highlights a significant difference in brain shrinkage between genders.

As individuals grow older, brain volume decreases, losing both grey and white matter. The findings indicate that men's brains shrink more significantly, particularly in the cortex, which is crucial for cognitive functions like memory and decision-making. In contrast, women's brains tend to maintain a stable cortex thickness despite some volume loss in specific areas.

Interestingly, the hippocampus, the region associated with memory, does not show notable shrinkage differences between genders until later in life for women. This delayed decline may be attributed to women's longer life expectancy, rather than a direct correlation with neurodegenerative diseases.

This presents a puzzling contradiction: while brain shrinkage is often associated with Alzheimer's, it doesn't necessarily indicate disease, but rather may reflect the natural aging process. Further research is required to fully understand the reasons behind women's increased vulnerability to Alzheimer's despite lower rates of brain shrinkage.

In summary, the study emphasizes the complexity of brain health and Alzheimer's risk, suggesting that ongoing research is essential to uncover the underlying factors contributing to these gender disparities.