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How Does Acupuncture Really Work?

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This is a difficult question to answer because current research is showing that acupuncture doesn’t work via a singular pathway. Instead, acupuncture causes a cascade of small and complex changes.

Here is a brief list of what we do know about what is happening during acupuncture:

Acupuncture reduces pain and inflammation

Evidence is showing increasing numbers of pathways that this is occuring, but here are the most established:

Opioid based

Acupuncture encourages the release of endorphins that work through opioid receptors on the parasympathetic nervous system to reduce pain (1).

A landmark study in 1976 showed that this pain relief achieved by acupuncture can be blocked with Naloxone (an opioid antagonist)(2). This means that acupuncture works along the same mechanism as opioid medications, without taking medication and without the risk of addiction.

Non-opioid based

Studies have since shown that acupuncture has significant effects on other neurotransmitter receptors in the body, including adrenergic, serotonergic, cholinergic and GABAnergic(3). This suggests that acupuncture doesn’t increase the levels of norepinephrine, serotonin, acetylcholine and GABA in our body, but can change our receptivity to what we have - making the most of what we’ve got.

Neurological - Limbic system

fMRI brain mapping studies have shown that acupuncture can consistently reduce activity in certain parts of the brain (the limbic-paralimbic-neocortical network)(4). The outcome is that acupuncture can reliably reduce perception of pain and, oedema and inflammation(5,6). Part of its effect is mediated through specific opioid receptors at the spinal dorsal horn.

A 2007 study showed that electrical acupuncture significantly increased paw withdrawal latency in rats (a marker in animals equivalent to human pain syndromes)(7). This result didn’t appear in the subjects where the messaging to the spinal dorsal horn was blocked.

Hormonal

Acupuncture has been shown to produce increased levels of plasma corticosterone, cortisol and adrenocorticotropic hormone (ACTH) levels(8,9). When released short-term, these steroid hormones actively reduce inflammation.

Interestingly, a study applied acupuncture to a group of rats with acute inflammation compared to a group with no acute inflammation. Results showed that acupuncture increased the release of these steroid hormones only where there was acute inflammation. When the same acupuncture was administered on rats without acute inflammation, there was no shown increase in steroid hormone levels. It would suggest that acupuncture can activate an anti-inflammatory response when require(5).

Acupuncture releases myofascial trigger points

Myofascial trigger points are those hard knots in your muscles. When pressed, they can be tender or painful. They can also refer pain elsewhere or cause muscle twitching.

Acupuncture has been long-known for releasing sore and tight areas in muscles. While the traditional Chinese term is ashi points, this correlates directly to what is now commonly referred to as trigger points.

Studies have shown that needle insertion into or close to an active trigger point can release muscle hypertonicity and begin a cascade of biochemical changes to increase blood and oxygen supply to the local area. This can decrease local inflammation and pain and increase range of motion and muscular function(11).

Qualified acupuncturists are trained to move through different densities of soft tissue and understand how much “work” is required to release myofascial trigger points.

Acupuncture regulates cortisol levels and has a potentially positive affect on depression

Following similar fMRI studies that map brain activity, acupuncture has also been shown to down regulate the amygdala and hypothalamus(12).

These parts of the brain are involved in emotions, memories and arousal (stimulation). An overactive limbic system can be involved in mood disorders (eg. depression), generalised anxiety and post-traumatic stress disorder.

A recent systematic review of 13 randomly controlled trials found that treating depression with acupuncture (with medication) is superior compared to using medication alone. Acupuncture has an early onset of action and was safe and well-tolerated. Electric acupuncture has a greater effect than manual acupuncture(5).

Acupuncture helps regulate reproductive functions via affecting blood circulation to the ovaries and uterus

Acupuncture has been shown to regulate uterine and ovarian blood flow. This is mediated through the ovarian sympathetic nerves and then supraspinal pathways(12).

There are varied measured outcomes. The most significant at the moment is that acupuncture can affect a thicker uterine wall(13). Increased research is underway to measure the impact of these changes to outcomes of embryo implantation and clinical pregnancy rates.

For complex gynaecological conditions like Polycystic Ovarian Syndrome, it is suggested that acupuncture may exert some affect through a variety of mechanisms - neurological, hormonal and directly on local blood circulation surrounding the reproductive organs.  

Evidence is still unclear of the efficacy of using acupuncture to treat gynaecological conditions. While earlier systematic reviews found that the effectiveness of acupuncture used to support IVF technology was unclear, a more recent study found that “based on analysis of the studies, acupuncture improved clinical pregnancy rates among women undergoing IVF.”(14)




References:

  1. Sjolund B, Terenius L, Ericsson M: Increased cerebrospinal fluid levels of endorphins after electroacupuncture. ActaPhysiol Scand 1977, 100: 382-384

  2. Pomeranz B, Chiu D: Naloxone blockade of acupuncture analgesia: endorphin implicated. Life Sci 1766, 19:1757-1762

  3. Kim W, Kim SK, Min BI. Mechanisms of electroacupuncture-induced analgesia on neuropathic pain in animal model. Evid Based Complement Alternat Med. 2013;2013:436913. doi:10.1155/2013/436913

  4. Fang J, et al. The salient characteristics of the central effects of acupuncture needling: limbic-paralimbic-neocortical network modulation. Human Brain Mapping 2009; 30: 1196-206.

  5. Napadow V, Ahn A, Longhurst J, et al. The status and future of acupuncture mechanism research. J Altern Complement Med. 2008;14(7):861–869. doi:10.1089/acm.2008.SAR-3

  6. Zhang RX, Wang L, Liu B, Qiao JT, Ren K, Berman BM, Lao L, Mu opioid receptor-containing neurons mediate electroacupuncture-produced anti-hyperalgesia in rats with hind paw inflammation. Brain Res. 2005 Jun 28; 1048(1-2):235-40.

  7. https://www.sciencedirect.com/topics/nursing-and-health-professions/paw-withdrawal-latency

  8. Li A et al. Corticosterone mediates electroacupuncture-produced anti-edema in a rat model of inflammation. BMC Complement Altern Med. 2007 Aug 14;7:27.

  9. Lao L, Zhang G, Wei F, Berman BM, Ren K Electro-acupuncture attenuates behavioral hyperalgesia and selectively reduces spinal Fos protein expression in rats with persistent inflammation. J Pain. 2001 Apr; 2(2):111-7.

  10. Butts R, Dunning J, Perreault T, Mourad F, Grubb M (2016) Peripheral and Spinal Mechanisms of Pain and Dry Needling Mediated Analgesia: A Clinical Resource Guide for Health Care Professionals. Int J Phys Med Rehabil 4:327. doi: 10.4172/2329-9096.1000327

  11. Hui KK, Marina O, Liu J, Rosen BR, Kwong KK. Acupuncture, the limbic system, and the anticorrelated networks of the brain. Auton Neurosci. 2010;157(1-2):81–90. doi:10.1016/j.autneu.2010.03.022

  12. Chan YY, Lo WY, Yang SN, Chen YH, Lin JG. The benefit of combined acupuncture and antidepressant medication for depression: systematic review and meta-analysis. J Affect Disord. 2015 May 1;176:106-17

  13. Stener-Victorin E, Waldenström U, Andersson SA, Wikland M. Reduction of blood flow impedance in the uterine arteries of infertile women with electro-acupuncture. Hum Reprod. 1996 Jun; 11(6):1314-7.

  14. Qian Y, Xia XR, Ochin H, Huang C, Gao C Therapeutic effect of acupuncture on the outcomes of in vitro fertilization: a systematic review and meta-analysis Arch Gynecol Obstet. 2016