Is Placebo Acupuncture What It Is Intended to Be?

This scientific commentary by Lundeberg and colleagues offers a fundamental critical analysis of the methodologic validity of controlled acupuncture studies, questioning whether placebo or sham acupuncture procedures are truly inert as intended. The work examines data from large German studies conducted in the 2000s, involving thousands of patients with migraine, low back pain, and knee osteoarthritis. The results of the German GERAC (German Acupuncture Trials) revealed a surprising pattern: minimal acupuncture (superficial needling away from traditional points) showed efficacy similar to true acupuncture and was significantly superior to standard treatment. In migraine, for example, 51% of patients treated with true acupuncture had a reduction in attack frequency, compared with 46% with minimal acupuncture — an insignificant difference.

More importantly, both forms of acupuncture were superior to standard medication (47%) and far superior to oral placebo (24%). In low back pain, minimal acupuncture was effective in 41% of cases versus only 27% for standard treatment. The authors explain these findings through multiple physiologic mechanisms. First, any form of needling, even superficial, activates cutaneous and nociceptive receptors that send signals to the brain, modulating areas such as the limbic system involved in pain processing.

Neuroimaging studies show that in healthy individuals, sham acupuncture results in activation of limbic structures, whereas in patients with pain there is deactivation of these same structures — suggesting adaptive mechanisms specific to the clinical condition. The article highlights that different pain etiologies respond differently to sensory stimulation. Musculoskeletal pain of inflammatory or ischemic origin showed a higher likelihood of improvement, while neuropathic pain responded less. This reflects the cortical reorganization that occurs in the transition from acute to chronic pain, affecting the descending pain-modulation circuits.

The authors also address the role of the reward system and expectation. Positron emission tomography studies demonstrate that the placebo effect involves dopamine release in the ventral striatum and activation of opioid and serotonergic pathways. The ritual context of acupuncture may function as an emotion-focused therapy, enabling psychological reorientation even with sham needling. Additional evidence comes from hormonal studies showing that both true and sham acupuncture alter plasma cortisol levels, indicating a centrally mediated hypothalamic response.

In patients with irritable bowel syndrome, both groups improved quality of life without between-group differences, but only the true-acupuncture group showed a decrease in salivary cortisol and an increase in parasympathetic tone. The methodologic implications are profound. If sham acupuncture is not inert, as the physiologic and clinical evidence demonstrates, then the current design of controlled clinical trials may be introducing bias against acupuncture rather than reducing it. The authors argue that comparing acupuncture with sham acupuncture is like comparing two active interventions, not an intervention against a true placebo.

The article concludes by recommending that acupuncture's efficacy be evaluated primarily through comparison with standard treatments, considering individual responses and the specific etiology of the condition treated. This perspective revolutionizes the interpretation of decades of acupuncture research and suggests that the therapeutic effects may have been consistently underestimated owing to fundamental methodologic flaws in study design.