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How Acupuncture May Relieve Pain: What the Research Shows
Pain can significantly affect quality of life. Most pain involves one or more processes: sensitization at the site of injury, increased sensitivity in the spinal cord, and changes in how the brain processes pain. Research suggests acupuncture may act on each of these, although much of the mechanism research comes from laboratory and animal studies.
At the site of pain
Pain often starts where tissue is injured or inflamed. Needle stimulation activates nerve fibres and may promote the release of natural pain-relieving chemicals such as endorphins. One study measured changes in sciatic nerve blood flow with acupuncture and electroacupuncture in patients with low back and leg symptoms (Inoue et al., 2008).
In the spinal cord
When pain signals are frequent or intense, the spinal cord can become over-responsive, so that even light touch hurts. In a rat model of nerve pain, electroacupuncture reduced this over-sensitivity by calming immune cells in the spinal cord (Gim et al., 2011). Whether the same happens in people is still being studied.
In the brain
Brain-imaging research shows acupuncture changes activity in networks involved in pain (Zyloney et al., 2010). In a randomized, sham-controlled trial in people with fibromyalgia, acupuncture was associated with changes in serotonin and substance P levels (Karatay et al., 2018).
What this means for patients
The strongest evidence that acupuncture helps patients comes from clinical trials, not mechanism studies. A large analysis of about 20,000 patients found acupuncture reduced chronic back, neck, knee and headache pain more than sham acupuncture or no acupuncture, although the difference compared with sham was modest (Vickers et al., 2018). Research activity is growing quickly, with hundreds of clinical studies on acupuncture for pain published each year (Li et al., 2024), but the number of studies alone doesn’t prove effectiveness.
References
- Gim, G.-T., Lee, J.-H., Park, E., Sung, Y.-H., Kim, C.-J., Hwang, W.-W., Chu, J.-P., & Min, B.-I. (2011). Electroacupuncture attenuates mechanical and warm allodynia through suppression of spinal glial activation in a rat model of neuropathic pain. Brain Research Bulletin, 86(5–6), 403–411. https://doi.org/10.1016/j.brainresbull.2011.09.010
- Inoue, M., Kitakoji, H., Yano, T., Ishizaki, N., Itoi, M., & Katsumi, Y. (2008). Acupuncture treatment for low back pain and lower limb symptoms: The relation between acupuncture or electroacupuncture stimulation and sciatic nerve blood flow. Evidence-Based Complementary and Alternative Medicine, 5(2), 133–143. https://doi.org/10.1093/ecam/nem050
- Karatay, S., Okur, S. C., Uzkeser, H., Yildirim, K., & Akcay, F. (2018). Effects of acupuncture treatment on fibromyalgia symptoms, serotonin, and substance P levels: A randomized sham and placebo-controlled clinical trial. Pain Medicine, 19(3), 615–628. https://doi.org/10.1093/pm/pnx263
- Li, Z.-Q., Wang, X.-F., Feng, C., Fei, Y.-T., & Liu, J.-P. (2024). Global trends of acupuncture clinical research on analgesia from 2010 to 2023: A bibliometric and visualization analysis. Frontiers in Neurology, 15, Article 1368988. https://doi.org/10.3389/fneur.2024.1368988
- Vickers, A. J., Vertosick, E. A., Lewith, G., MacPherson, H., Foster, N. E., Sherman, K. J., Irnich, D., Witt, C. M., & Linde, K. (2018). Acupuncture for chronic pain: Update of an individual patient data meta-analysis. The Journal of Pain, 19(5), 455–474. https://doi.org/10.1016/j.jpain.2017.11.005
- Zyloney, C. E., Jensen, K., Polich, G., Loiotile, R. E., Cheetham, A., LaViolette, P. S., Tu, P., Kaptchuk, T. J., Gollub, R. L., & Kong, J. (2010). Imaging the functional connectivity of the periaqueductal gray during genuine and sham electroacupuncture treatment. Molecular Pain, 6, Article 80. https://doi.org/10.1186/1744-8069-6-80