Acupuncture may produce its effects through dynamic alterations in the tissue and extracellular milieu: generates micro injuries, characterized by cytoskeletal remodeling of subcutaneous connective tissue fibroblasts and deformation of extracellular matrix proteins; induces the synthesis and release of cytokines, chemokines, and growth factors from skin, muscle, and endothelial cells promoting healing and resolve inflammation; induces the local release of endogenous opioids (β-endorphin) and cannabinoids; and regulates the metabolism of stress hormones like catecholamines.
According to traditional beliefs, disease and chronic pain results from an insufficiency or blockage of vitality (similar to Qi or life force) and stimulation of acupuncture points along meridians (routes through which Qi travels) alleviates pain by restoring the flow of vitality. Clinicians assert that patients with higher vitality respond to acupuncture better.