Acupuncture triggers a cascade of biological responses, from the release of natural pain-relieving molecules at the needle site to measurable changes in brain activity. It’s used most commonly for chronic pain conditions, but it also has strong evidence for preventing nausea and is recommended by the American College of Physicians as a first-line, non-drug treatment for low back pain.
What Happens at the Needle Site
When an acupuncture needle is inserted and rotated, it causes minor, controlled disruption to the tissue beneath the skin. Cells in the area release a burst of ATP, the molecule your cells use for energy, which quickly breaks down into adenosine. In human subjects, adenosine levels at the needle site rise to roughly 178% of their baseline during treatment and stay elevated even after the needles are removed. Adenosine binds to receptors on nearby nerve fibers that carry pain signals to the spinal cord, temporarily dialing down the transmission of those signals. Notably, this adenosine release only happens when the needle is inserted at specific acupuncture points and rotated. Simply inserting a needle without manipulation doesn’t produce the same chemical response.
The needle also physically tugs on the connective tissue beneath the skin. As the tissue stretches, fibroblasts (the cells responsible for maintaining connective tissue) change shape and expand in response to that mechanical pull. This process, called mechanotransduction, is thought to contribute to the local therapeutic effects of treatment, potentially influencing blood flow and tissue repair in the area.
How It Affects the Brain
Brain imaging studies using fMRI show that acupuncture doesn’t just work locally. Needle manipulation on the hand, for example, produced widespread decreases in activity across brain regions involved in pain processing, emotional reactivity, and stress responses. Areas that quieted down included the amygdala (which processes fear and emotional reactions), the hippocampus (involved in memory), the hypothalamus (which regulates stress hormones), and the anterior cingulate cortex (a region that shapes how unpleasant you perceive pain to be). The only region that showed increased activity was the somatosensory cortex, the part of the brain that registers physical touch and sensation.
This pattern is significant. The brain areas that decrease in activity during acupuncture overlap heavily with the networks responsible for making pain feel distressing, not just detecting it. That may help explain why many people report that acupuncture changes their relationship with pain rather than simply blocking it. Interestingly, the two subjects in the imaging study who felt sharp pain from the needles rather than the typical acupuncture sensation showed the opposite brain response: increased activity in many of those same regions.
What the Needles Feel Like
Acupuncture doesn’t feel like getting a shot. The needles are hair-thin and flexible, and most people describe a distinctive sensation called “de qi” once the needle reaches the right depth. This is commonly felt as a deep ache or soreness, tingling or numbness, a sense of fullness or pressure, or heaviness around the needle site. The sensation often radiates outward from the point. Practitioners consider de qi a sign that the treatment is working, and from the practitioner’s side, a successful insertion feels like the tissue is gripping or pulling on the needle.
Not every insertion produces strong de qi, and that’s normal. Some points are more sensitive than others, and individual sensitivity varies widely.
Chronic Pain: What the Evidence Shows
The largest analysis of acupuncture for chronic pain pooled individual data from thousands of patients across multiple high-quality trials. It found that acupuncture outperformed both no treatment and sham acupuncture (where needles are placed at non-acupuncture points or don’t penetrate the skin) for back and neck pain, osteoarthritis, and chronic headaches.
To put the numbers in practical terms: in a typical trial where patients started with a pain score of 60 out of 100, those receiving no acupuncture improved to about 43, sham acupuncture brought scores down to 35, and real acupuncture reduced pain to around 30. When “success” was defined as at least a 50% reduction in pain, about 30% of untreated patients hit that mark, compared to 42.5% with sham acupuncture and 50% with real acupuncture. The gap between real and sham acupuncture was modest but statistically consistent across conditions, suggesting the specific needle placement matters beyond any placebo effect.
Based on this kind of evidence, the American College of Physicians included acupuncture in its 2017 clinical guidelines as a recommended first-line treatment for both acute and chronic low back pain, to be tried before medications.
Preventing Nausea and Vomiting
One of acupuncture’s most well-supported uses is preventing post-surgical nausea. Stimulation of a single point on the inner wrist, known as PC6, has been studied in dozens of randomized trials. Compared to sham treatment, stimulating this point reduced the risk of nausea by about 32%, vomiting by 40%, and the need for anti-nausea medication by 36%. When compared head-to-head with standard anti-nausea drugs, PC6 stimulation performed equally well. And combining wrist point stimulation with anti-nausea medication worked even better than drugs alone, cutting the risk of vomiting nearly in half.
Side effects from wrist point stimulation were minor: occasional skin irritation, redness, or mild discomfort at the site, all temporary and self-resolving.
Safety and Side Effects
Acupuncture is generally low-risk when performed by a trained practitioner. The most commonly reported side effects across hundreds of systematic reviews are mild: pain at the needle site, minor bleeding or bruising, dizziness, small hematomas, and occasional digestive symptoms like nausea. Fainting (syncope) can occur, particularly in first-time patients or those who are anxious, dehydrated, or haven’t eaten. Serious complications like organ injury or infection have been documented in the literature but are rare and typically linked to inadequately trained practitioners.
Insurance Coverage and Access
Medicare Part B covers acupuncture exclusively for chronic low back pain, defined as pain lasting 12 weeks or longer with no identifiable structural cause (not related to cancer, infection, surgery, or pregnancy). Coverage allows up to 12 sessions within 90 days. If you’re improving, Medicare will cover an additional 8 sessions, for a maximum of 20 treatments per year. If there’s no improvement, coverage stops and you’re responsible for the full cost of any further sessions.
There’s a significant catch with Medicare: the program cannot pay licensed acupuncturists directly. Your provider must be a physician, nurse practitioner, or physician assistant who also holds a master’s or doctoral degree in acupuncture from an accredited program and maintains a full, unrestricted state license. This requirement limits access in many areas. Private insurance coverage varies widely, so it’s worth checking your specific plan. Many people pay out of pocket, with sessions typically ranging from $75 to $150 depending on location and provider.