Scientists are finally decoding how acupuncture eases pain

A needle prick doesn’t seem like it should quiet severe pain. But in some cases, it does—easing migraines, dulling pain, even helping patients endure childbirth. In one randomized trial in emergency settings, acupuncture relieved acute pain more quickly and effectively than intravenous morphine, with fewer side effects.

Acupuncture, a practice rooted in Traditional Chinese Medicine (TCM), has long occupied a gray zone between medicine and mystery: widely used to treat pain, yet often dismissed as a placebo.

But advances in imaging and clinical research are shifting that view. Scientists are uncovering how a needle can trigger a chain reaction inside the body, activating immune cells, releasing pain-modulating chemicals, and altering brain activity. What’s emerging is a clearer picture of a measurable, body-wide response—one that is helping position acupuncture as a low-cost, non-addictive option in pain management worldwide.

The mystery of the needle

For centuries, the language of Traditional Chinese Medicine—concepts like meridians and qi, or vital energy—left many Western researchers unconvinced.

That disconnect is now narrowing. As clinical research has progressed, scientists are gaining a clearer picture of what happens when a needle meets tissue, says Mingxiao Yang, an assistant professor at Nanyang Technological University in Singapore, whose integrative health lab explores TCM through cutting-edge technology.

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The response begins locally. The slight mechanical tug of a needle, known as mechanotransduction, sets off a cascade of biochemical signals in the surrounding connective tissue. This activity causes skin mast cells (think of them as your body’s first line of defense) to release compounds such as histamine, serotonin, and adenosine into nearby tissue. Those signals then stimulate nerve endings, sending messages to brain regions involved in processing and modulating pain.

Acupuncture may also engage broader pain-regulation pathways, including a “pain inhibits pain,” sensation, in which one stimulus can dampen the perception of another, Yang explains.

Some touch-based therapies, such as massage, may trigger overlapping responses through mechanical stimulation of connective tissue, though the mechanisms remain under study.

TCM under the scope

In recent years, advances in imaging have made acupuncture’s once-hidden effects increasingly visible. High-field fMRI scans show how stimulation at specific acupoints is associated with changes in brain activity, including regions involved in pain processing and emotional regulation.

Meanwhile, soft X-ray imaging has captured immune cells drifting toward acupuncture needles, where they release pain mediators. Even ultrasounds are helping researchers observe the ripple effect of a needle’s tug in real time and how those effects may vary depending on where a needle is placed.

Together, these tools are beginning to map how a localized stimulus can ripple across the body—linking peripheral tissue, immune responses, and the brain’s pain-processing networks. Psychologically, the mere anticipation of potential healing plays its own role too, Yang adds. “Treatment expectancy and belief, mediated partly through the brain’s reward circuitry, may also contribute to acupuncture-induced pain relief.”

A comprehensive theory of acupuncture remains out of reach, but researchers are beginning to identify patterns that could help predict who benefits most. “In particular, I’m interested in the possibility of identifying biomarkers that predict treatment response and help us better understand which patients are most likely to benefit,” says Yang.

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Some studies have also explored how traditional acupuncture maps align with anatomy. Researchers have reported an 80 percent overlap between classical meridian pathways and connective tissue networks, regions that appear to contain higher densities of nerve fibers than surrounding areas. One analysis found that these dense points may contain 1.4 times as many nerve fibers as non-acupoints.

“The traditional map of the meridians should be reinterpreted as a profound, ancient blueprint of the body’s neural and fascial networks,” says Judith Schlaeger, a professor at the College of Nursing at the University of Illinois in Chicago. “The most effective points are often those that act as high-access ports to the nervous system.”

Fake needles, real relief

For decades, one question has lingered: Does acupuncture work beyond the placebo effect? Answering that has proved difficult.

“The ‘true face’ of acupuncture remained elusive,” says Schlaeger. “Investigators lacked the ability to use the definitive clinical methodology—the double-blind randomized controlled trial—to separate acupuncture’s genuine physiological effects from the placebo effect.”

That barrier may finally be shifting. Her team has just completed what they describe as the world’s first double-blind acupuncture trial (where neither the participants, 89 women suffering from chronic vulva pain, nor the researchers themselves knew if real or sham needles were administered).

The trial was made possible by a specially designed placebo needle, developed by Nobuari Takakura of Tokyo Ariake University of Medical and Health Sciences, which conceals the depth of needle penetration. He explains that “without a double-blind study environment, the decoding of the mechanisms of acupuncture would be impossible, because investigators wouldn’t be able to distinguish its true physiological effect from the power of expectation.”

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The team’s findings, recently published in the Journal of Pain, show that both real and sham acupuncture work can provide relief, just not equally. True acupuncture offers much longer-lasting relief of up to 12 weeks in some cases, while relief from the placebo diminished after four weeks. Since true acupuncture creates a micro-injury that releases a burst of chemical substances, “the central nervous system is excited,” Schlaeger explains, “triggering the body’s natural long-term repair mechanisms.”

Takakaura adds, this shows that while the placebo-powered relief of ‘the ritual of care’ exists, “relief fades quickly because there is no lasting stimulus. This is the clear boundary between the fleeting nature of placebo versus the sustained effect of a true intervention.”

Even so, questions remain. Larger studies and replication will be needed to confirm these findings and determine how broadly they apply.

Ancient healthcare meets new

Understanding how acupuncture works does more than satisfy scientific curiosity. It could reshape how pain is treated globally—offering a low-cost, non-addictive option even as health systems search for alternatives to pharmaceuticals. Long embedded in healthcare systems across China and other parts of Asia, acupuncture is also used more widely in countries such as Germany, where public insurance has covered it for certain chronic pain conditions since 2007.

Kim Sungchol, unit head for Traditional, Complementary, and Integrative Medicine at the World Health Organization (WHO), is hoping such evolutions continue. His team is propelling the WHO’s Global Traditional Medicine Strategy 2025–2034, which aims to integrate evidence-based traditional practices into modern healthcare systems. “According to the most recent WHO global reports on traditional and complementary medicine, acupuncture is now the most extensively used intervention worldwide within this field,” notes Kim.

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As the evidence base grows, acupuncture may also serve as a gateway for broader acceptance of other traditional therapies, from herbal medicine to meditation—many of which are now studied with increasing clinical rigor.

The results could be transformative. In the United States, where the opioid crisis has claimed more than a million lives since 2000, non-pharmacological approaches to pain management are gaining renewed attention. Some studies suggest acupuncture may reduce both postoperative pain and the need for opioid medications, though results vary.

“Ultimately, the vision for 2034 is not about promoting one system over another, but about stronger health systems that reflect how people seek care,” says Kim.