Although more than two million acupuncture treatments are performed each year, critics of the 2,500-year-old procedure have long claimed the benefits to be purely psychological. However, a study by a team of scientists from two British universities found distinct differences in the brain’s response to acupuncture needles when compared with tests using "dummy needles" that did not puncture the skin. Researchers at the University of London found that the part of the brain that manages pain and the nervous system responded to acupuncture needles and improved chronic pain relief by as much as 15%. That may not sound like much, but it is the same size improvement that you would get from taking conventional analgesic drugs.

The study involved fourteen patients who were put through one of three tests in random order: blunt needles which pricked the skin but did not penetrate, dummy needles that were pushed back by the skin, and actual acupuncture treatment. Brain maps created using positron emission tomography showed that all three tests caused the brain to release natural opiates in response to the expected effect of the needles. But, only real needles produced an extra effect and stimulated another part of the brain, the ipsilateral insular.