How Acupuncture Works | The Science of Acupuncture – Acupuncture & Dry Needling, Santa Monica, CA

The scientific basis of Acupuncture is now well understood. There is no longer a need to get lost in esoteric discussions of “Qi” and “meridians” as they relates to acupuncture. A summary of the science is given below, however, note that the physiology of acupuncture treatment can be a bit complex.

First off, we can start with debunking the basic history of Chinese Medicine and how we are generally told that acupuncture works. The Western idea that Chinese medicine is an energetic, metaphysical medicine was created by a French bank clerk named Georges Soulie de Morant in the early 1900’s. Unfortunately, de Morant lacked any training in medicine or ancient Chinese language. De Morant’s explanation of concepts like Qi and Meridians was neither historically accurate nor consistent with science, even the science of the time.

“It is a fact that more than 95 percent of all literature published in western languages on Chinese medicine reflect western expectations rather than Chinese historical reality.”

-Paul Unschuld, historian of Chinese medicine

More on this topic can be found in Chris Kresser’s article on Chinese Medicine Demystified.

Acupuncture has been shown to act on several mechanisms in the body, and the details of these mechanisms are discussed below. These physiological mechanisms can become complicated, however the basis of acupuncture is quite simple. Acupuncture’s effect is dependent on the stimulation of the peripheral nervous system (PNS). This has been confirmed by the fact that when nerves innervating acupoints are blocked acupuncture has no effect.

Research suggests that acupuncture stimulates the central nervous system to release natural chemicals that alter hormonal output, pain response, and other biological processes. In 2003, the World Health Organization (WHO) conducted an extensive review and analysis of clinical trials involving acupuncture. According to this report acupuncture impacts the body on multiple levels, concluding it:

Stimulates conduction of electro-magnetic signals, which can promote immune system cells or pain-killing chemicals.
Activates the body’s endogenous opioid system, which may help reduce pain and induce better sleep quality.
Stimulates brain centers including the hypothalamus and pituitary gland, which modulate numerous body systems.
Changes in the secretion of neurotransmitters and endocrine hormones, which may positively effect brain chemistry.

In the World Health Organization’s video, a team of researchers, including an acupuncturist, conducted an experiment for the first time in history. Using MRI imaging techniques, the research study visually demonstrated that acupuncture has a very real and measurable effect on the brain. Acupuncture does something completely remarkable – it deactivates certain area of the brain, particularly in the limbic system. In this process there is decreasing neuronal activity, which in turn suppresses pain and overactive nervous system patterns (as opposed to having an activating neuronal impact). Their experiment also clearly showed that fake (sham) needling did NOT have this effect. The limbic system is a deep brain center associated with the experience of pain, adding further evidence that something very unique happens during acupuncture treatment. Acupuncture fundamentally alters the experience of pain by shutting down these deeper brain regions that are over-active in chronic pain conditions and in chronic stress patterns.

In addition, scientific research on Acupuncture has shown measurable activity in specific body systems including:

Acupuncture increases peripheral blood flow. An increase in blood flow is significant because all tissues of the body need a rich supply of blood to heal and thrive. Blood brings oxygen, nutrients, vitamins, immune complexes, hormones, and anti-inflammatory substances. Restoring optimal blood flow is essential to promoting and maintaining health. Blood flow can be impacted by injuries, certain diseases and general aging. Acupuncture has been shown to increase blood flow and vasodilation in several regions of the body.
Acupuncture increases the neural pain threshold. This effect occurs through the release of natural painkillers. Inserting an acupuncture needle sends a signal from the peripheral nervous system to the brain and in response the brain releases chemicals such as endorphins, norepinephrine and enkephalin. Some of these natural substances are 10-200 times more powerful than opioid drugs such as morphine.
Acupuncture releases neurochemicals similar to endorphins which as been shown to reduce both the intensity and perception of chronic pain. It produces this effect through a process termed “descending control normalization”, which involves the serotonergic nervous system.
Acupuncture triggers the body’s innate healing mechanisms. Acu needles create “micro traumas” that stimulate repair of local tissues, ultimately leading to a faster healing of injuries. This involves stimulation to the tissues in the nervous, immune and endocrine systems. As the body responds to the micro traumas induced by acupuncture, it also heals any surrounding tissue damage left over from injuries.
Acupuncture relaxes shortened muscles. This in turn releases pressure on joint structures and nerves, and promotes blood flow. Muscles often develop trigger points which can be effectively be released through traditional acupuncture or trigger point dry needling.
Acupuncture reduces stress and subdues exaggerated stress responses. Suppressing the sympathetic nervous system (SNS) and reducing stress is arguably the most important system-wide effect of acupuncture. Research shows that acupuncture stimulates the release of oxytocin, a hormone that up-regulates the parasympathetic nervous system (PNS). The classic fight-or-flight state is governed by the SNS. In contrast, the PNS in common terms is the rest-and-digest system, also called the calm-and-connect system. Research has linked poor parasympathetic function (chronic stress) in a wide range of diseases including: autoimmunity, arthritis, lupus and inflammatory bowel disease.
Acupuncture increases T-cells and other immune constituents.
Acupuncture increases activity at nerve “gates”. Thermal PET scans also show activity in the regions of the brain responsible for pain messages.

And digging deeper into the science, acupuncture points appear to be special in that they have denser sensory innervation and connective tissue. Along with this, acupuncture points have higher density of TRPV1 receptors, which are important in pain signaling. Insertion of a needle into traditional acupuncture points creates a physical stimulus that activates mechanoreceptors and triggers afferent signals to the central nervous system (CNS), to areas in the brain which handle pain processing and response. Neurochemically, pain response is thereby down-regulated, and blood flow to the local area is increased, ultimately inducing acupuncture analgesia.

Both laboratory research and clinical data demonstrate that the endogenous opioid system is modulated in acupuncture analgesia. Consistently, studies show a reduced need for opioid drugs and other pain-reducing medications in patients with chronic pain after acupuncture treatment. In addition, the noradrenergic system has also been associated with acupuncture analgesia in experimental studies. In this system, acupuncture can induce a decreased level of noradrenaline in the brain was observed after acupuncture. Studies in animal models of inflammatory and neuropathic pain have also found evidence for a role of serotonin and glutamate in acupuncture analgesia. Other pain mediators that have been suggested to be modulated by acupuncture include somatostatin, cannabinoids, and neurotrophic factors. However, clinical studies supporting these additional theories are limited at this time.

Experimental models of pain have also indicated that acupuncture may have an anti-inflammatory action by having a modulatory effect on the release of pro-inflammatory mediators. These results have been supported by clinical findings showing a reduction in the production of pro-inflammatory molecules after acupuncture in patients with osteoarthritic pain and chronic pelvic pain syndrome.

The following reference websites can provide you with additional information on acupuncture research and the science of acupuncture:

World Health Organization (WHO)
National Center for Complementary and Alternative Medicine (NCCAM)
Connective Tissue Fibroblast Response to Acupuncture: Dose-Dependent Effect of Bidirectional Needle Rotation
The Science of Stretch
Chris Kresser, LAc – Chinese Medicine Demystified