"It is no longer possible to say that the effectiveness of acupuncture can be attributed to the placebo effect or that it is useful only for musculoskeletal pain."

— Stephen Janz

The discussion below overviews the work of Mel Hopper Kopperman (Hopper Koppelman, 2017, abbreviated HK below, full reference at the bottom of the page).

Stephen Janz and John McDonald set up  The Acupuncture Evidence Project in 2017, updating the evidence through compiling the findings of almost 1000 systematic reviews in the acupuncture literature. In a bibliometric analysis of the use of acupuncture over 27 years Birch et al (2018) found 2189 positive recommendations for 204 health issues in guidelines published in North America, Europe and Australia.

The mechanism of how acupuncture works has always been much debated.  Many biochemical and signalling pathways have been identified but it has now been demonstrated that the most central explanation for the mechanism of the therapy for such an array of conditions is that acupuncture initiates a process called purinergic signalling, essentially using a complex communication network around the body. In brief, “specific biomolecules mediate short term signalling functions in neural transmission, secretion and vasodilation, and long term  signalling functions in cell proliferation, differentiation and regeneration”(Burnstock, 2014).

Pharmaceutical companies are currently attempting to develop drugs to inhibit or enhance purinergic signaling (Borea PA et al, 2016), which could be an issue as the balance of the biomolecular compounds such as adenosine and ATP at the cellular level is delicate, and both too much and too little of them are associated with disease. In contrast, acupuncture treatment improves self-regulation of purinergic signalling, which is likely to be both effective and safe.

In addition to biochemical actions, studies also demonstrate the direct effect of acupuncture on the central nervous system. These include spinal reflex effects, where acupuncture stimulates muscle relaxation and changes in visceral organs. It has been shown that acupuncture can modulate the activity of the limbic structures in the brain which are associated with stress and illness (Cho Zh et al., 2006). It can also regulates the function of the HPA (hypothalamic-pituitary-adrenal) axis, the primary system that the body uses for regulating the physiological stress response.

Acupuncture also modulates parasympathetic nervous system activity, which is the branch of the nervous system associated with rest, relaxation, digestion and tissue healing (Lund I, Lundbergh T, 2016).  

In summary, research into the mechanisms and effectiveness of acupuncture is getting closer to providing an explanation which better fits with modern medical science. I am hopeful, that as a parallel to the harmonisation of body systems brought about through acupuncture treatment, this deepened understanding will bring harmony and coherence to the practice of Acupuncture and Chinese Medicine alongside conventional medicine.

References
Hopper Koppelman, M. ( 2017)  Acupuncture : An overview of Scientific Evidence ( https://www.evidencebasedacupuncture.org/acupuncture-scientific-evidence/#foot_text_17841_29 , viewed 17/08/2019)