PNAS Publishes Review on the Scientific Mechanisms of Acupuncture

The Proceedings of the National Academy of Sciences (PNAS) — one of the most prestigious scientific publications in the world — dedicated space in its Volume 123 (Issue 10) for an in-depth review on the state of the science of acupuncture. Written by science journalist Lynne Peeples and published in March 2026, the article synthesizes decades of research on the mechanisms by which medical acupuncture produces its clinical effects — and presents the project that may definitively transform the field: TARA, funded by NIH, which uses 3D imaging and artificial intelligence to map acupoints with unprecedented anatomic precision.

Endogenous opioids and adenosine: the pharmacology of the needle

One of the most solidly established findings is that the insertion of needles at acupoints stimulates the release of endogenous opioids — endorphins, enkephalins, and dynorphins — in addition to adenosine, a nucleoside with potent local analgesic effect. These neurotransmitters modulate nociceptive transmission at multiple levels: at the site of peripheral stimulation, in the dorsal root ganglia, in the posterior horn of the spinal cord, and in the descending inhibitory pathways of the brainstem. The result is pharmacologically mediated analgesia and, therefore, measurable and predictable.

Brain networks: beyond local analgesia

Functional neuroimaging studies (fMRI) demonstrate that acupuncture modulates entire brain networks — not only isolated nociceptive pathways. The salience network, the default mode network, and the limbic system, which integrates the affective and cognitive dimensions of pain, respond in a characteristic way to acupuncture stimulation. This explains why medical acupuncture can be effective not only for the sensory dimension of pain, but also for its emotional components — anxiety, catastrophizing, and suffering associated with chronic pain.

What the meta-analyses confirm

The PNAS article highlights that individual-patient-data meta-analyses — the highest methodologic level for the analysis of clinical evidence — consistently confirm that acupuncture surpasses sham treatments for chronic pain. More importantly: the benefits persist for at least one year after the end of treatment, suggesting modifying and not just symptomatic effects. The conditions with documented positive evidence include: chronic musculoskeletal pain (neck pain, low back pain, osteoarthritis), headache and migraine, infertility, climacteric symptoms, cancer-related fatigue, asthma, and irritable bowel syndrome.

The TARA project: artificial intelligence in service of acupoints

The TARA project (Traditional Acupuncture Research Anatomy), funded by NIH, represents the most advanced frontier of acupuncture research. Using high-resolution three-dimensional anatomic images and artificial intelligence algorithms, the project seeks to map with millimetric precision the location of acupoints, their relationships with neurovascular and tissue structures, and the pathways of transmission of acupuncture stimuli. The final objective is to integrate the millennial knowledge of traditional medicine with modern anatomy and physiology — creating an objective cartographic base for evidence-based clinical practice.