Most acupuncture studies applies sham acupuncture as a mean to use placebo in acupuncture studies.
As John Amaro writes in his article at Acupuncturetoday.com Is Most of Acupuncture Research a "Sham?",
"Acupuncture research conclusions cannot be accepted as long as the research is being conducted as shown in the examples I cited. True blind or double-blind studies may essentially be impossible within acupuncture research due to the fact as long as a patient is able to feel a sensation at the point of needle contact (whether actual or simulated), it cannot be considered a valid blind study. The methods utilized in most acupuncture research are without question, a "sham.""
it is not possible to use sham acupuncture as placebo. Placebo is supposed to be without any effect and since sham acupuncture is designed to simulate the de Qi sensation I would say that they are using a placebo-method that is not without an effect.
Sham needling is shallow or just in contact with the skin. Japanese acupuncture has a philosophy of inserting needles shallow or not at all, so called touch needling, and still get effect. Japanese acupuncturist also have the aim to insert the needle with as little pain or sensation for the patient as possible.
Researchers should look beyond Chinese acupuncture and a little bit more to Japanese practitioners, specially Manaka that did a lot of research in acupuncture. Before applying bad study designs which usually show bad results, research should be done on the X-factor as described by Manaka in the "Chasing the Dragons tail". Which also elaborates the effects of needling on the same side contra the opposite side of pain. Reserch should also be done on how different needling methods gives signals in the body osing MRI and other tools not as poorly designed studies with sham acupunture as controlling element.