The findings still need to be confirmed in follow-up studies.
A computer algorithm found women used a higher proportion of glucose to develop their brain, showing their brains were younger.
Subjects ranged from their 20s to 80s, and across those age spans, women's brains appeared metabolically younger than men's, said the findings in the Proceedings of the National Academy of Sciences, a peer-reviewed USA journal.
Still, much more research is needed.
"It's not that men's brains age faster - they start adulthood about three years older than women, and that persists throughout life", Goyal told the news outlet. I think this could mean that the reason women don't experience as much cognitive decline in later years is because their brains are effectively younger, and we're now working on a study to confirm that'.
Our bodies use the pair of chemicals to sustain brain development as we grow from children to adults via a process known as aerobic glycolysis.
In reverse, they trained the algorithm on women's data and applied it to men's.
The study enrolled 121 women and 84 men, who underwent PET scans to measure brain metabolism, or the flow of oxygen and glucose in their brains. They used the women's data as a baseline, and estimated the men's ages based exclusively on their metabolism data.
They then fed a machine-learning algorithm the male sample data to establish a relationship between age and brain metabolism. The algorithm yielded brain ages an average of 3.8 years younger than the women's chronological ages.
Interestingly, the gap between men and women's brain ages was detectable even in young adults in their 20s.
Scientists measuring the brain activity of more than 200 people found that female brains were more youthful than those of males of the same age.
The researchers noted that the relative "metabolic youth" of women's brains also parallels the slightly longer life span of women, compared with men.
"It's not that women's brains seem to age slower than men's", Goyal said.
More studies are now needed to better understand this brain-age difference and whether it affects the risk of age-related brain disease, such a Alzheimer's.