ATLANTA (CNN) -- Researchers have discovered that the female hormone estrogen can significantly reduce the amount of brain damage suffered after a stroke.

When a stroke cuts off the brain's life-sustaining blood supply, women usually suffer less brain damage than men, which researchers believe is a result of estrogen.

A study published in the American Heart Association's Journal Stroke reveals that men, too, can benefit by receiving just one dose of the female hormone shortly after suffering a stroke.

"Administration of estrogen reduces to a very large degree -- as much as 50 percent to 60 percent -- the amount of brain injury that occurs after a stroke," said Patricia Hurn of Johns Hopkins University.

Taking "replacement" estrogen over extended periods of time has been known to help women reduce the painful side effects of menopause and help protect them against osteoporosis and heart disease.

With a man, "one might not be so interested in using a hormone which is associated with feminizing effects," Hurn acknowledged. But, she added, a one-time dose for men can be just as helpful for them as taking the hormone over time.

Because premenopausal women, with naturally high levels of estrogen, are less likely to suffer a stroke, researchers will now try to determine if estrogen can prevent strokes from occurring.

"I think these data give some promises that there is a very simple, naturally occurring substance that produces protection," Hurn said.

CNN Correspondent Holly Firfer contributed to this report.