Most commentators here seem to think acupuncture is quackery.
I do not.
When I receive acupuncture, I experience sensations that are specific to acupuncture and different from the calming experience of meditation, massage, or yoga (all different). Of course, N=1, and confirmation bias, etc.
My biggest issue with the way research on acupuncture is conducted in the West is that, in my opinion, the causal model used is complete nonsense. Sham acupuncture is not an appropriate research strategy. The unit of treatment is “practitioner skilled in modality plus patient”; you can compare clinical outcomes vs. clinical outcomes with other protocols but you cannot compare sham to actual.
The reason people go for this nonsense is because people think of acupuncture as being like a drug or surgery. It is not. Acupuncture is much more like talk therapy. It is a conversation between practitioner and patient, mediated by needles. You would never be foolish enough to try double-blind trials of talk therapy, because the communication model is obvious, but because many people believe in linear causality in the medical world, they think this approach to researching the efficacy of acupuncture is appropriate.
As @wanderfound points out, there is a wide range of efficacy in “placebo” treatments. I think the word placebo is not the most useful one, because it is often read as “invalid” or “fake”, rather than “rhetorically effective”.
The concept of rhetorical efficacy is the best option when we are trying to understand the experiential phenomena that some people describe as “chi” or “ki”. For example, any person who has taken an introductory class in Ki Aikido will have had their instructor demonstrate the difference between lifting a person who is holding ki in their belly and lifting a person who is focusing ki downward. Two incoming students can always take the arms of the first person and lift them off the ground. Those same incoming students can never (almost never?) lift that same person when the intended liftee is focusing their ki downward. Why? I’ve spoken with curious Aikido instructors who have focused their ki downward while standing on bathroom scales. Their weight does not observably change. The only way they could be consistently generating such an experientially overwhelming effect is through a reliable form of nonverbal communication – communicating “I am heavy” without needing words to do so, in a way that other participants reliably find convincing.
This is rhetorical efficacy. The mechanism of communication is not the important part; the important question is, “are patients reliably experiencing changes in their bodies as a result of the interaction with this practitioner or class of practitioners?”
Acupuncture is rhetorically effective, particularly when practiced skilfully. Not all patients find it so, and often you need a good match between patient and practitioner, but the various clinical studies of pain treatment that have found acupuncture to be effective have at least shown us that people’s bodies are often convinced not to feel pain.
For these reasons, I strongly disagree with the prevailing mood on this thread!