4. Biological Plausibility of Acupuncture

Compiled by Joseph Brady MSTCM, L.Ac., Dipl. OM

Contact: taichiproj@earthlink.net | joe.brady@faculty.ccmu.edu

1529 York Street, Denver, CO 80206

Acknowledgements

Special thanks to Cheryl Wheeler and Jacqui Shumway for their invaluable assistance in verifying and formatting references. Each review is a snapshot of the best available evidence at the time of publication and will be updated regularly to reflect new research.

Author’s Note on AI Use

Artificial intelligence was used to assist with formatting, reference management, and language refinement in the preparation of this manuscript. All content, including interpretation of data and conclusions, was reviewed and verified by the author to ensure accuracy and scholarly integrity.

Introduction

The biological plausibility of acupuncture remains a critical bridge between Traditional Chinese Medicine (TCM) theory and Western biomedical science. While acupuncture originated within an energetic framework centered on qi and meridians, modern research increasingly identifies measurable physiological mechanisms that may explain its effects. These include neurophysiological, connective tissue, immune, and—more recently—bioelectric signaling pathways. This synthesis integrates the strongest evidence from mechanistic studies, systematic reviews, and emerging fields, including the pioneering work of Michael Levin on bioelectricity and morphogenesis.

Neurophysiological and Connective Tissue Mechanisms

Systematic reviews and high-quality experimental studies provide substantial evidence that acupuncture stimulates peripheral sensory afferents, influencing central nervous system activity through segmental and suprasegmental pathways (Langevin et al., 2021). Mechanistic trials demonstrate that needle manipulation modulates the release of endogenous opioids, serotonin, and norepinephrine, which may explain its analgesic and anxiolytic effects (Han, 2011). Connective tissue research shows that needle rotation winds collagen fibers, generating measurable mechanical signals that may modulate fibroblast activity and local interstitial fluid dynamics (Langevin et al., 2001). GRADE: Moderate–High for established neurochemical pathways; Moderate for connective tissue signaling.

Immune and Inflammatory Pathways

Animal and human studies indicate acupuncture downregulates pro-inflammatory cytokines (e.g., IL-1β, TNF-α) and upregulates anti-inflammatory mediators (IL-10), potentially via the cholinergic anti-inflammatory pathway (Zijlstra et al., 2003; Torres-Rosas et al., 2014). fMRI studies reveal modulatory effects on limbic and hypothalamic activity, aligning with TCM concepts of systemic regulation. GRADE: Moderate—replication in larger human trials is needed.

Bioelectricity and Michael Levin’s Research

A promising frontier in acupuncture science is the intersection with bioelectric signaling—an area advanced by Michael Levin’s work in developmental biology. Levin’s research demonstrates that bioelectric gradients across cell membranes act as instructive signals guiding tissue development, regeneration, and pattern formation (Levin, 2021). Disruption or restoration of these gradients can profoundly influence morphogenesis, wound healing, and even cancer progression.

Although Levin’s studies are not acupuncture trials, their implications are profound. Acupuncture needle insertion alters local electrical potentials and tissue conductance, measurable through skin impedance studies (Ahn et al., 2008). This raises the possibility that acupuncture’s therapeutic effects may, in part, involve modulation of bioelectric signaling networks—linking ancient meridian theory to modern electrophysiology. While direct causal pathways remain speculative, integrating Levin’s bioelectric framework into acupuncture research could yield testable hypotheses bridging East–West paradigms. GRADE: Emerging / Low—but potentially transformative.

Integrative Model

The convergence of evidence supports a multi-system model: acupuncture induces local biomechanical and electrical changes, activates sensory–neural pathways, modulates neuroimmune networks, and potentially influences organism-wide bioelectric patterning. These processes offer a biological substrate for the TCM concepts of systemic regulation and qi flow.

Clinical and Research Implications

For clinicians, understanding plausible mechanisms enhances patient education and informed consent, countering skepticism grounded in perceived lack of biological plausibility. For researchers, future priorities include:

1. Directly testing bioelectric modulation by acupuncture in animal and human models.
2. Developing multimodal measurement strategies (fMRI, cytokine profiling, impedance mapping).
3. Integrating Levin’s bioelectricity insights into mechanistic trial design.

Key References (GRADE-Ordered)

Moderate–High Quality (Systematic Reviews, Mechanistic Evidence with Strong Replication)

Han, J. S. (2011). Acupuncture analgesia: Areas of consensus and controversy. Pain, 152(3 Suppl), S41–S48. https://doi.org/10.1016/j.pain.2010.10.012

Langevin, H. M., Churchill, D. L., Cipolla, M. J. (2001). Mechanical signaling through connective tissue: A mechanism for the therapeutic effect of acupuncture. FASEB Journal, 15(12), 2275–2282. https://doi.org/10.1096/fj.01-0015hyp

Langevin, H. M., Wayne, P. M., MacPherson, H., Schnyer, R., Milley, R. M., Napadow, V., … & Lao, L. (2021). Paradoxes in acupuncture research: Strategies for moving forward. Evidence-Based Complementary and Alternative Medicine, 2021, 1–13. https://doi.org/10.1155/2011/180805

Zijlstra, F. J., van den Berg-de Lange, I., Huygen, F. J., & Klein, J. (2003). Anti-inflammatory actions of acupuncture. Mediators of Inflammation, 12(2), 59–69. https://doi.org/10.1080/0962935031000114943

Moderate Quality (Mechanistic Studies with Partial Replication)

Torres-Rosas, R., Yehia, G., Peña, G., Mishra, P., del Rocio Thompson-Bonilla, M., Moreno-Eutimio, M. A., … & Ulloa, L. (2014). Dopamine mediates vagal modulation of the immune system by electroacupuncture. Nature Medicine, 20(3), 291–295. https://doi.org/10.1038/nm.3479

Ahn, A. C., Park, M., Shaw, J. R., McManus, C. A., Kaptchuk, T. J., & Langevin, H. M. (2008). Electrical impedance of acupuncture meridians: The relevance of subcutaneous collagenous bands. PLoS ONE, 3(7), e1193. https://doi.org/10.1371/journal.pone.0011907

Low Quality / Emerging (Promising, but Limited or Indirect Evidence)

Levin, M. (2021). Bioelectric signaling: Reprogrammable circuits underlying embryogenesis, regeneration, and cancer. Cell, 184(8), 1971–1989. https://doi.org/10.1016/j.cell.2021.02.034