Researchers tested three options: traditional acupuncture; minimal acupuncture, in which a few needles were placed on meaningless points; and no treatment. While the traditional acupuncture group experienced the most improvement, participants who received the minimal acupuncture also enjoyed some relief. Investigators are not sure why. One suggestion is that acupuncture even at inaccurate points still alters circulation and stimulates release of natural pain relievers; another possibility is that acupuncture has a high placebo effect. Additional studies are needed to find out more.