How Does Acupuncture Work? The Science Explained

Neurochemical Effects

When an acupuncture needle is inserted, it stimulates sensory nerve fibres (A-delta and C fibres) which transmit signals to the spinal cord and brain. This triggers the release of endogenous opioids — the body's own pain-relieving chemicals including enkephalins, dynorphins, and beta-endorphins — at both the spinal and supraspinal levels.

Acupuncture also releases serotonin and noradrenaline, which activate the descending pain inhibitory pathway — a spinal mechanism that 'turns down the volume' on pain signals from throughout the body. This explains why acupuncture at a distal point (say, the hand) can relieve pain in a completely different part of the body (say, the neck).

Brain Imaging Evidence

Functional MRI (fMRI) studies have demonstrated that acupuncture produces measurable changes in brain activity. The limbic system — the brain's emotional and pain-processing hub — shows significant deactivation during and after acupuncture. The default mode network, chronically overactive in people with chronic pain and depression, normalises with regular acupuncture treatment.

These are not placebo effects: sham acupuncture (needles in wrong locations or non-penetrating placebo needles) produces different patterns of brain activation than real acupuncture, confirming that specific needle placement produces specific neurological effects.