Why does acupuncture work? I'm planning to go to a free session next week, purely out of curiosity, but I still want to know why. Surely the stated premise here— that we're all infused with Qi or "life energy" that gets clogged up now and again and just needs a bit of needling—is all just a bunch of arrant nonsense, right? I mean, right? Luckily, we have a less-mystical theory, courtesy of Scientific American:

[A] medicinal procedure like acupuncture may work for some other reason not related to the [Qi theory]. Electroacupuncture--the electrical stimulation of tissues through acupuncture needles--increases the effectiveness of analgesic (pain-relieving) acupuncture by as much as 100 percent over traditional acupuncture. ... Ulett posits that electroacupuncture stimulates the release of such neurochemicals as beta-endorphin, enkephalin and dynorphin, leading to pain relief. In fact, he says, the needles are not even needed--electrically stimulating the skin... is sufficient. Ulett cites research in which, using this technique, the amount of gas anesthetic in surgery was reduced by 50 percent.

These findings might help explain the results of a study published in the May 4, 2005, issue of the Journal of the American Medical Association, in which Klaus Linde and his colleagues at the University of Technology in Munich compared the experiences of 302 people suffering from migraines who received either acupuncture, sham acupuncture (needles inserted at nonacupuncture points) or no acupuncture. During the study, the patients kept headache diaries. ... The results were dramatic: "The proportion of responders (reduction in headache days by at least 50%) was 51% in the acupuncture group, 53% in the sham acupuncture group, and 15% in the waiting list group." The authors concluded that this effect "may be due to nonspecific physiological effects of needling, to a powerful placebo effect, or to a combination of both."

Hm. Although I can totally see how a "powerful placebo effect" could unblock the Qi...