Acupuncture relieves pain. Exactly how acupuncture needles in the skin achieve pain relief is not known and is not easily testable. If acupuncture cannot be tested by standard clinical experiments then Western medical regulators will remain loath to certify it as a legitimate medical treatment.
Acupuncture downregulates (or turns off) pro-inflammatory cells known as M1 macrophages. Acupuncture also upregulates (or activates) anti-inflammatory M2 macrophages, thereby reducing pain and swelling. M2 macrophages are a source of anti-inflammatory interleukin-10 (IL-10); by upregulating M2 macrophages, acupuncture leads to an increase in IL-10, which subsequently helps relieve pain and inflammation