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Chinese Medicine Demystified (Part IV): How Acupuncture Works


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Note: This is the fourth article in an ongoing series. Make sure to read the previous articles before reading this one, and check out the next articles in the series afterwards.

In this post we’re going to explore how acupuncture works from a western scientific perspective. As I’ve argued in the previous articles, there is no disagreement between the fundamental anatomical and physiological concepts of western and Chinese medicine. However, as methods of scientific inquiry have progressed, the mechanisms of acupuncture are beginning to be more clearly understood.

Acupuncture effects every major system of the body, including the cardiac, gastrointestinal, circulatory, cerebral, genitourinary, endocrine and immune systems.

It would take an entire book to describe all of the mechanisms involved, and in fact there is such a book for those who are interested in that level of detail. In this post my purpose is to summarize that research in a way that’s easy for lay people to understand, while providing links to more technical resources for medical professionals and others that might be interested.

Broadly speaking, acupuncture has three primary effects:

  1. It relieves pain.
  2. It reduces inflammation.
  3. It restores homeostasis.

Homeostasis refers to the body’s ability to regulate its environment and maintain internal balance. All diseases involve a disturbance of homeostasis, and nearly all diseases involve some degree of pain and inflammation. In fact, research over the last several decades suggests that many serious conditions like heart disease previously thought to have other causes are in fact primarily caused by chronic inflammation. If we understand that most diseases are characterized by pain, inflammation and disturbance of homeostasis, we begin to understand why acupuncture can be effective for so many conditions.

Several modes of action have been identified for acupuncture, which I’ll discuss below. The mechanisms can get quite complex.

But ultimately acupuncture is a remarkably simple technique that depends entirely upon one thing: the stimulation of the peripheral nervous system. It’s important to point out that when nerves supplying acupoints are cut or blocked there is no acupuncture effect.

A large body of evidence indicates that acupoints, or “superficial nodes” as they are more accurately translated, have abundant supply of nerves. According to Chen Shaozong, “For 95% of all points in the range of 1.0 cm around a point, there exist nerve trunks or rather large nerve branches.” 1

The following is a list of mechanisms that have been identified so far:

  • Acupuncture promotes blood flow. This is significant because everything the body needs to heal is in the blood, including oxygen, nutrients we absorb from food, immune substances, hormones, analgesics (painkillers) and anti-inflammatories. Restoring proper blood flow is vital to promoting and maintaining health. For example if blood flow is diminished by as little as 3% in the breast area cancer may develop. Blood flow decreases as we age and can be impacted by trauma, injuries and certain diseases. Acupuncture has been shown to increase blood flow and vasodilation in several regions of the body.
  • Acupuncture stimulates the body’s built-in healing mechanisms. Acupuncture creates “micro traumas” that stimulate the body’s ability to spontaneously heal injuries to the tissue through nervous, immune and endocrine system activation. As the body heals the micro traumas induced by acupuncture, it also heals any surrounding tissue damage left over from old injuries.
  • Acupuncture releases natural painkillers. Inserting a needle sends a signal through the nervous system to the brain, where chemicals such as endorphins, norepinephrine and enkephalin are released. Some of these substances are 10-200 times more potent than morphine!
  • Acupuncture reduces both the intensity and perception of chronic pain. It does this through a process called “descending control normalization”, which involves the serotonergic nervous system. 2 I will explain this process in further detail in the next post.
  • Acupuncture relaxes shortened muscles. This in turn releases pressure on joint structures and nerves, and promotes blood flow.
  • Acupuncture reduces stress. This is perhaps the most important systemic effect of acupuncture. Recent research suggests that acupuncture stimulates the release of oxytocin, a hormone and signaling substance that regulates the parasympathetic nervous system. You’ve probably heard of the “fight-or-flight” response that is governed by the sympathetic nervous system. The parasympathetic nervous system has been called the “rest-and-digest” or “calm-and-connect” system, and in many ways is the opposite of the sympathetic system. Recent research has implicated impaired parasympathetic function in a wide range of autoimmune diseases, including arthritis, lupus, rheumatoid arthritis and inflammatory bowel disease.

Several other mechanisms have been identified, but the ones I’ve listed above are the most relevant and clearly understood.

Some purists object to acupuncture being described in biomedical terms. They claim that such descriptions are “reductionistic” and narrow-minded, and don’t take into account those aspects of acupuncture that we may not yet understand.

Others who are still committed to the “energy meridian” model are opposed to the biomedical descriptions because, in their eyes, such scientific inquiry “takes the magic” out of acupuncture.

While I agree that there we don’t yet fully understand how acupuncture works, I think it’s vital that practitioners of acupuncture are able to explain what we do know about it from a biomedical perspective to their patients and colleagues in the medical profession.

As practitioners we have a moral obligation to provide each patient with the latest medical understanding available in terms they can understand and relate to. Doing this will improve patient outcomes and open the door for acupuncture to be integrated into the healthcare system, which is needed now more than ever.

I would also suggest that explaining the mechanisms of acupuncture in scientific terms should not in any way lessen our appreciation of its uniqueness. The fact that inserting fine needles into the skin can have such a broad range of powerful effects is just as remarkable when those effects are explained in terms of the nervous system as when they are explained in terms of “energy” and “meridians”. When you consider that the Chinese made these discoveries hundreds of years before the birth of Christ, acupuncture is even more impressive.

What’s more, as others have pointed out, acupuncture is inherently holistic even without the “energy meridian” theory because it restores internal homeostasis through the simple act of piercing the skin with a needle.

In the next article I’ll explain the latest theory on how acupuncture relieves pain in more detail. Stay tuned!

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  1. Shaozong, C. Modern acupuncture theory and its clinical application. (Chapter 5 The Morphologic Relationship between Points and Nerves). International Journal of Clinical Acupuncture. 2001;121(2):149-158
  2. Dung HC. Anatomical features contributing to the formation of acupuncture points. American Journal of Acupuncture. 1984;12:139-143
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Join the conversation

  1. Your series is very interesting, and I know there is a desire among many Westerners to understand Chinese Medicine in Western terms, but I do not agree that there is a “moral obligation” on the part of practitioners to be able to trot those mechanisms out on demand. If you can successfully treat patients and have them recover from their illness, is it that important that patients know the physiological mechanisms that do the job? Do patients in the West know how the statin drugs they are taking do what they do, and why? Do they even know why the aspirin they take helps alleviate their headache? On the other side of the coin, do successful treatments based on Meridian Theory mean that the acupuncturist just got lucky, while poking around in the dark? I think there is much more work to be done in reconciling the thought processes and perceptions of East and West.

    • I see where you’re coming from, but I can’t agree with your analogies. I do believe patients should be informed about how statins work (and don’t work, actually) so they can decide whether they need to take them at all, or can use other less invasive, less harmful methods. The same for aspirin. I also believe – and the research clearly supports this – that when a patient 1) has a positive attitude about their treatment, and 2) believes that it will work, the treatment will be more effective. Explaining how acupuncture works in language they can understand is a step in that direction for most, although there’s certainly a minority of patients (and practitioners) that prefers a more mystical, magical explanation.

  2. Nicely done chris,

    I too am a senior student of Dr. Tan, and the Master Tung style.  I apprecaite your knowledge and explanation.  I talk about this all the time.  There is NO ENERGY required to do acupuncture.  It works off of very biologicaly and scientific reasons.  Very easy to understand.  As we know, energy is in everything, and at a quantum level we are ALL ENERGY…but this is NOT WHY OR WHY NOT acupuncture works or doesnt work….

    thank you….now lets see if we can cant change the entire TCM school system to quit propagating these lies about the invisible meridians and Qi that MISTRANSLATED…it means “vital air”, as in OXYGEN…not energy.

    i urge any acupuncturist a MUST MUST MUST MUST read or anybody who want to know the truth of a very scientific and discplined chinese medicine…read

    The Dao of Chinese medicine, by Kendall……

    Bob doane is a master at explaining this, so Dr. Kendall. 

    I see over 30 patients by myself each day, i work with doctors–western and Eastern.  And do we talk methaphorically about the concepts of chinese medicine? Yes, it helps us understand the disease process.  But when it comes to how acupuncture works, there is no use for mistranslated explanations from 1910’s and the 1950’s. 


    the magic is the bodies ability to heal once it is given the right healing modality.  that is the true magic, the power of the human body, wether we use Eastern medicine, Western medicine, or NO MEDICINE….the body is amazing

    thanks again chris, nicely done!!!!

  3. Yes, I do use pulse diagnosis but no, there is no scientific explanation that I’m aware of.  It’s a mystery, but it works.

    • Hi Chris, Just want to say thanks again for all the great info.
      I heard on one of your podcast you mentioned that acupuncture can increase blood flow to the brain, and this could an important mechanism for how it works. Are there any points in particular that have been shown to do this, or are you looking at the “big” points like ST36, SP6, Liv3, Li4 etc?
      Also, I am interested in learning pulse diagnosis – can you recommend any books/sources that might be worthwhile reading? It seems like a bit of an art but I have definately noticed some changes after needling- do you use it much in your practice?
      Thanks again, Marley- New Zealand

      • Oh yeah, my partner has just gone past her due date- do you recommend any points for induction of labour (using Li4, SP6, ST36, K8, BL62 and TW22 at the mo). Are you a dad soon too?

  4. yeah that makes sense, we seem to live in a very pro-sympathetic world. It ties into the stuff you have said about the omega 3-6 imbalance and the chronic inflammation that arises. Personally I am allergic to most fish , although I have just started trying fish oil and this seems ok. I have always had various allergies/asthma & ITP so the lack of omega 3 probably doesnt help
    . Do you use pulse diagnosis , and is there any science behind this?

  5. Yes, my understanding is that the concha of the ear is the most accessible site for influencing the vagal nerve.  I use ear points in every single treatment because there’s not a person I see that doesn’t need some parasympathetic support.

  6. Thanks for the reply chris,
    Both TCM and the western principles are amazing in their own way, so its nice to hear a mixed approach works. At the moment we are learning about the sympathetic and parasympathetic systems and how needling the ear or scalp points can decrease inflammation through the vagal nerve. Fascinating stuff

  7. Hi, thanks for the interesting reading. I am a physiotherapist currently studying western acupuncture and am learning alot about the pathways you have described. I am also trying to pick up on some of the TCM principles which is difficult at times, but its good to know there is a common ground between the two approaches. Is there any danger of treating patients with acupuncture without understanding all of the TCM philosophies? For example, does the direction of twisting the needle actually tonify or sedate the ‘meridian’? Or if I use a point from a western approach, can it have some adverse effect based on TCM?
    It explain now why we are still using the same points from thousands of years ago

    • I’ll get myself in trouble with other acupuncturists for saying this, but I don’t believe the various needle techniques (twisting, inserting while breathing in or out, etc.) affect the clinical results much. My acupuncture teacher, Dr. Tan, who lectures all over the world and is a very successful practitioner, doesn’t either – so I’m not alone. I don’t think there’s much danger in performing Western acupuncture without understanding the TCM philosophies. I say that because acupuncture is historically a channel-based therapy, not a “zang fu” therapy as herbal medicine is.

  8. What is completely missing from your explanations is how acupuncture works without inserting a needle to stimulate the body’s healing response.  Contact needling by blind acupuncturists in Japan obtains equivalent and sometimes better results than acupuncture that punctures the skin with a needle.  Poorly designed clinical trials fail to show statistically significant differences between control groups and experimental groups because they stimulate the same points with toothpicks, obtaining a favorable health result even without the insertion of needles.  You have a done a nice job of trying to overlay Western on Chinese, but you miss out entirely on elements that are going on outside of your isolated explanations: like with contact needling, or Qi Gong healing.  These modalities have the same effects as acupuncture (without a needle to stimulate the Western mechanisms you have described).

    • Crystal,

      Penetrating the skin isn’t required to stimulate a PNS response. Contact or toothpick needling would not promote the local tissue response to needling I described, but it could induce the PNS-mediated analgesic response (i.e. activation of the C-delta fibers and subsequent release of endorphins).

      There’s still a lot we don’t understand about how it works, and I never claimed that the explanation I offered was exhaustive. However, there’s absolutely no evidence supporting the notion of “energy” flowing through invisible meridians.

      I am a long-time practitioner of internal arts such as Qi Gong, Taiji and Ba Gua. There is nothing about these practices that requires the idea of Qi as energy to explain their effectiveness.

  9. I’ve always been open to “alternative” medicine and acupuncture, but I’ve been a little skeptical because of the believes in the energy and meridian concepts. I’ve been thinking that if acupuncture works it must have something to do with either blood flow or nerve stimulation. And this is exactly what you’re saying, so I’m very happy now and can finally think of acupuncture as a complement to nutrition etc. Many thanks for this!
    I’m curious. How long does the vascular dilation effect from needle stimulation last? And does it only affect blood flow nearby or does it dilate blood vessels more distant from the stimulated point?
    Even if acupuncture for instance can give pain relief I think it’s important to choose the right tool for the right job. Michelle, commenter above, has shoulder pain. I immediately think of posture and if she is sitting much and how. I think that should be looked at first and not use acupuncture right away because that will give some relief. One should search for the root cause first before starting treatment. I have no education in the medicine field, I just read a bunch on the Internet and this is my opinion. Do you share this opinion? But this is not easy, you have to know a great deal about nutrition, emotional stress, posture and muscles, environmental toxins etc to find the real cause.
    Having said that, I’d be very interested in hearing what issues you think acupuncture can be the primary treatment method for? Or do you think acupuncture is more useful as a catalysator and helping the body to heal faster after you’ve eliminated the root cause?
    Many thanks for the articles. I believe I have one more part to read  🙂

    • Tim,

      I’m glad you’re enjoying the series. To answer your questions in turn:

      The sources I’ve read suggest the neuroimmune response from acupuncture lasts for two to three days. The effect is systemic. Studies have shown that acupuncture increases blood flow to the internal organs via the vagus nerve.

      I agree that it’s always best to find the root cause of the problem. Acupuncture is just one branch of Chinese medicine. It’s kind of like the “physical therapy” of Chinese medicine, in fact. If a patient were to come in with a weight problem, of course the first thing I would do is ask them about their diet. Acupuncture wouldn’t help much in that case if their diet was making them fat. As you’ll see if you peruse my blog, I write mostly about nutrition and lifestyle factors affecting health, so I am in complete agreement with you about their importance.

      That said, acupuncture can sometimes help speed the transition. In the case of shoulder pain you mentioned, it’s important to address both the symptom (pain) and the cause (poor posture). We can do both at the same time.

      Here’s a list of conditions the World Health Organization has stated can be successfully treated with acupuncture. The list is likely much larger, but it’s a good place to start.

  10. Eliza,

    Who I’d recommend depends on what you’re wanting help for.  Contact me using this form with that information and I’ll make a referral.

    The problem with the studies comparing so-called “sham” acupuncture to “real” acupuncture is that the sham treatment is not inert.  In other words, the sham treatment ends up activating the same systemic healing responses that real acupuncture does.

    If we understand the neurological basis of acupuncture, then it makes sense that almost any area of the body will be an acupuncture point (because there are nerve endings just about everywhere except for nails and hair).  However, it’s been shown that acupoints have a denser concentration of nerve endings and vascular structures, so we might expect those points to work better than non-points.  Some studies show this is the case, and others do not.

    Speaking from my own experience, point selection does matter.  Other practitioners – and even patients – will tell you the same thing.  I’ve had patients who responded to my treatments that didn’t respond to other treatments, and vice versa.  Granted, we can’t say for sure that point selection was what made the difference.  But we can’t say for sure that it wasn’t.

    Overall I do think the effects of acupuncture are primarily holistic, meaning that it stimulates the body’s self-healing ability rather than specifically addressing a particular condition.  I see this as a tremendous advantage.  It means that when someone goes in for elbow pain, not only will that improve, but their depression, IBS and hypertension are also likely to improve.

    This is the opposite of what happens with western medicine, where a “specific” treatment for a particular condition (i.e. taking a drug for depression) ends up causing several other new problems (i.e. anxiety, constipation, decreased libido, etc.)

  11. Can you recommend any East Bay practitioners?
    Curious, too, if you have any comments on the study of so-called “sham” acupuncture being just as effective as traditional acupuncture. Perhaps it doesn’t even matter where the needles are placed?

  12. Chris,
    How many treatments do you recommend for your patients before you evaluate the effectiveness for that patient’s injuries?

    • Dave,

      There are numerous facts that determine the rate of response to treatment, including age, overall state of health, blood flow in the circulatory system, how chronic the injury is, how serious the trauma was, the nutritional status of the patient, whether they are taking medications and at what dosage, etc. I’d say there are no fewer than 40 factors involved in the answer to this question, so it’s not easy to give an estimate without actually seeing you in person. That said, I would estimate that it takes between 3 and 5 treatments to adequately determine future rate of response. Ideally, those treatments should be confined to a 2 or 2.5 week period, i.e. at least 2x/wk treatment.

  13. Chris, this is one post where we agree EXACTLY.  I’d like to add one question to stimulate discussion:
    Acupuncture stimulates nerve fibers as proven by experiments such as those conducted by Pomeranz, Stux and Berman.  This is physiologic as this stimulation (de qi sensation) is obliterated by naloxone administration.  (In fact, I had heard from one patient that this was the straw that broke the skepticism’s back – since naloxone blocked the effect, then it IS physiologic and not just some mystical claptrap).  My question is thus: can not the other hemostatic effects of acupuncture be explained by the fact that sensory input passes through the hypothalamus before going to their respective brain areas?  This, plus the fact that the hypothalamus contains several nuclei involved in body regulation?

  14. Okay, I may have investigated as much as I’m going to. With my limited knowledge, what you say seems plausible. I look forward to the next post. One thing though: could you provide a reference for the statement about acupuncture stimulating release of oxytocin? I’m curious about that.

    • The acupuncture-oxytocin research is still very new. But see here and here for more info. There is abundant evidence that acupuncture stimulates the parasympathetic nervous system regardless of the involvement of oxytocin.

  15. Any kind of injury to the tissue: sprains, tears, pulls, contusions, etc. of muscle, ligament or tendon.

  16. Thanks for answering my comment! I see. Interesting. Your answer leads me to another question though: What characteristics differentiate damaged tissue from healthy tissue? I mean, what it is that makes damaged tissue “damaged?” Is it an open wound that still hasn’t healed or something?

  17. Thank you!  I’ve been wary of acupuncture for years because of the mysticism surrounding it.  I’m one of those people that needs to know why and how it works, not just that it works.  Even with my skepticism I’ve been considering getting it done to relieve the constant tension in my shoulders, now I think I’ll start looking for a practitioner in earnest.

    • Michelle,

      I’m so happy to hear that! That was exactly my mission in writing this series – to dispel the common misconceptions about Chinese medicine and increase it’s acceptance amongst patients and doctors. Let me know if I can be of help in finding a practitioner in your area.

      • Hi, Chris
        This article helped to validate the progress I have made since getting acupuncture treatments for almost a year now. I am going to be moving to Orem, Utah next month and I am having trouble finding a new acupuncturist online. I am not one of your patients (I have been consulting with Steve Wright from SCD Lifestyle) but I would really appreciate any guidance or advice you could give me in finding a practitioner!
        Thank you in advance, I really appreciate your time.

      • Hello

        I’ve been seeing an acupuncturist, she is Chinese, for an LSS (lumbar spinal stenosis). Symptoms: hot feet, weak legs to the point of collapsing if I push it), urgency to urinate sometimes. Tests done so far: cat scan, xrays of lower back and hips, full Doppler of legs and up to the sternum, EMG, now waiting for MRI. Conclusions: normal wear of L5 S1 for a 67 year old active male (ski instructor and motorcycle rider (road and trials). I’m using an inversion table plus getting acupuncture twice a week. I’m slowly starting to feel stronger and can use my legs longer before they start to crumble under me. May I have your opinion/experience on treating LSS by acupuncture. Thanks for a very informative site.

  18. Jesse,

    There are several factors which can impair wound and tissue healing:

    1. Developmental stage: children heal faster than adults because blood flow and fibroblastic ability decrease as we age.
    2. Poor circulation and oxygenation: physiological disorders such as diabetes and hypertension reduce circulation to peripheral tissues.  Smoking, anemia and respiratory disorders decrease oxygenation of tissues.  Obesity also delays healing because adipose tissue has a lower concentration of blood vessels.
    3. Emotional and physiological stress: chronic illness and emotional stress can impair tissue regeneration and wound healing.  Poor nutrition, certain medications and environmental toxins can also contribute.

    Acupuncture can “jump start” the body’s tissue regeneration and repair mechanisms in spite of these factors.  Of course the treatment will be far more effective if these factors are removed.

  19. I love this series. I have a friend who’s child had severe yeast issues and food intolences when he was young and now they’re gone, she credits acupuncture. Let me comment on the comment above me and please correct me if I’m wrong. Ever since my friend told me about her experience with acupuncture I have been trying to grasp why. I’ve spent a few lunchbreaks digging online and come up with an explanation for mydelf to grap it better: The immune system has several levels it opperates at. If you have an autoimmune diesease your body tends to live with chronic inflammation and the immune system responds to this one way, as you feel the daily aches and pains, let’s call this a low grade response.. When you catch the flu, for example, you immune system has another response, let’s call this a “high grade” response. Say, you discover what was causing your daily inflammation, like gluten. So you pull the gluten out of your diet and you feel better, but not 100 percent. Your “low grade” response still is a bit there. This is because you need the “high grade” response to clean up the damage caused by the gluten. You’ve stopped the additional inflammation by pulling the culprit, but there’s years of damage that needs to be fixed.
    The other part to this equation I am trying to learn more about is something called “healing regressions”, which I think works on the same priciple.

  20. I intend to investigate what you’ve said in more depth later, but for now I have one question, about your second bullet point: Why would micro traumas stimulate healing of old injuries more than the old injuries themselves would? Sorry for my ignorance.

    • Hey Jesse,
      I know you made your comment a while back but I wanted to answer your question.
      I am an Integrative Physiology student who is taking a class on Immunology right now.
      Whenever there is a trauma to a body part, the surrounding tissues release cytokines that tell nearby cells that there is an infection or trauma taking place, and this stimulates leukocytes (white blood cells) to come to the place of trauma and “fight off” or “heal” whatever is wrong. Cytokines also create swelling in the affected area by stopping blood flow so whatever pathogen is contained in the area can’t travel to the rest of the body via the blood (so there is increased blood amount at the site of trauma)
      When you create a micro trauma, this sends an even stronger release of cytokines and therefore more leukocytes come to the site of trauma. So in fact any old injuries in the area would be flooded with leukocytes and an increased blood amount and therefore would be easier to heal.
      Hope this helped! Let me know if you have any more questions.

        • So cytokines decrease overall blood flow to the affected area but they tell the leukocytes to move into the area (connective tissue area or epithelial area) that has been traumatized outside of the blood flow so that your body can start to heal. In this way, blood flow is increased meaning to leukocytes move into the affected area.

          • Ok let me see if I understand. Needles create trauma, inducing cytokine release, which attracts leukocytes and causes swelling so there’s extra blood overall (though less flowing through). And in places that have old injuries that didn’t heal properly, this helps them re-heal better. Is that right?

            • Yes that is exactly right! There are many cytokines that are released but a main one is called TNF-alpha. This cytokine is released by another leukocyte called a macrophage, and macrophages recognize any pathogen that enters your body (via a tear, needle, etc.).
              TNF-alpha does lots of things but first promotes more fluid, cells, proteins, and leukocytes to move into the affected tissue (swelling). Local clotting starts happening to stop blood flow and to not let pathogens spread. It also encourages leukocytes to flow to secondary lymph nodes to present pathogens so your body can better fight them. It also promotes the repair of the injured tissue which in turn helps repair any other tissue around it.