In mice given acupuncture, a molecule that's known to reduce pain is released, and when combined with drugs, offers even more relief from pain.
The natural pain-relieving chemical might help explain how acupuncture works, at least in mice.
Understanding how acupuncture affects humans is trickier because of how complicated pain is.
Uncovering the biological secrets of acupuncture could help legitimize it and convince more insurers to pay for it.
When they get acupuncture, mice release a natural pain-relieving molecule that scientists have never linked with the treatment before.
While it's not clear yet whether the finding will apply to humans, unraveling the biological secrets of acupuncture could help the therapy become a mainstream way to tackle pain.
"I think it's important that the Western world take acupuncture seriously," said Maiken Nedergaard, a neuroscientist at the University of Rochester in New York. "Many patients have unnecessary pain. I hope this can improve pain treatment."
Acupuncture has been around for thousands of years, and the World Health Organization has endorsed it for more than 20 conditions, but Western medicine continues to be skeptical about the practice.