Caffeine motivates female rats to have more frequent sex, a new study suggests. But don't start guzzling more coffee just yet.

Scientists gave 108 female rats a moderate dose of caffeine. The caffeine shortened the amount of time it took the females to return to males after a first romp, indicating they were more motivated to do it again.

Loading up on more caffeine is not expected to improve human sex drive in most cases, however.

"These rats had never had caffeine before," said study leader Fay Guarraci, an assistant professor of psychology at Southwestern University. "In humans, it might enhance the sexual experience only among people who are not habitual users."

The research could help scientists better understand sexual motivation, however.

"Understanding the circuits that control this behavior will help us understand how the brain works and what part of the brain mediates motivation because sexual behavior is a motivative behavior," Guarraci said.

The research will be detailed in the journal Pharmacology, Biochemistry and Behavior.

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