Acupuncture: What It Is, How It Works and What the Evidence Says
Acupuncture is a traditional Chinese medicine technique that involves inserting very fine needles into specific points on the body. Traditionally it is explained as a way of regulating the flow of Qi through the meridians; current research suggests modest benefits, mainly for some types of chronic pain and for nausea.
Key points
- Acupuncture inserts fine, sterile, single-use needles into points defined by Chinese tradition.
- Its traditional explanation is based on Qi and the meridians, concepts that have no demonstrated anatomical correlate.
- The strongest evidence concerns chronic pain (low back, neck, knee osteoarthritis, headaches) and nausea and vomiting.
- The 2021 NICE NG193 guideline considers a course of acupuncture as an option for adults with chronic primary pain.
- In the hands of a trained practitioner it is a technique with few serious adverse effects, although it is not risk-free.
- It does not replace medical diagnosis or treatment of serious illnesses.
Acupuncture is probably the best-known traditional Chinese medicine technique outside Asia. It involves inserting very fine needles into specific points on the surface of the body with the aim, according to tradition, of restoring the body's balance. In China it is usually named together with moxibustion under the term zhenjiu (针灸, zhēn jiǔ), literally "needle and fire," because both techniques have historically been practiced on the same points. On this page we explain where it comes from, what a session is like, what risks it carries and, above all, what we know today on a scientific basis.
What is acupuncture and where does it come from?
The first systematic descriptions of acupuncture appear in the Huangdi Neijing (黄帝内经, Huángdì Nèijīng), the Yellow Emperor's Inner Classic, a classical work compiled more than two millennia ago. It describes a network of channels through which Qi (气, qì), the vital energy or force, and Blood are said to circulate. Those channels are the meridians, and the acupuncture points lie along their pathways.
From the traditional standpoint, illness appears when Qi stagnates, weakens or circulates in a disorderly way, and the needles are meant to unblock, tonify or disperse it. This explanation is part of a broader conceptual framework that includes yin and yang and the zang-fu organs. It is important to stress that this is a traditional concept: to date, the meridians and Qi have no demonstrated anatomical or physiological correlate.
What is an acupuncture session like?
A first visit usually begins with a detailed interview and the examination typical of Chinese medicine, based on the four diagnostic methods: observation (including the tongue), listening and smelling, questioning, and palpation (including the pulse). From there, the practitioner chooses a combination of points.
What happens during treatment
- The person lies down or sits in a comfortable position.
- The skin is cleaned and anywhere from a few to about twenty sterile, disposable needles are inserted.
- The needles may be gently manipulated, warmed with moxa or connected to an electrical stimulation device (electroacupuncture).
- They are usually left in place for 15 to 30 minutes.
Most common variants
| Variant | What it involves |
|---|---|
| Manual acupuncture | Inserting and manipulating needles by hand |
| Electroacupuncture | The needles are connected to a low-intensity electrical current |
| Auriculotherapy | Stimulation of points on the outer ear with needles, seeds or small beads |
| Acupressure | Finger pressure on the points, without needles |
| Dry needling | A Western physical therapy technique that needles muscle trigger points; it is not based on meridian theory |
What is acupuncture used for?
In current clinical practice, acupuncture is used mainly for musculoskeletal pain (back, neck, knee), headaches and migraines, nausea, and as support for problems such as stress or insomnia. Tradition applies it to a much longer list of disorders, but the fact that it is used for something does not mean it has been shown to work for it. That is why it is important always to separate what tradition says from what studies show.
What does the scientific evidence say?
Acupuncture is by far the most researched Chinese medicine technique. Even so, studying it well is difficult: designing a credible placebo is not simple, so many trials compare real acupuncture with "sham acupuncture" (needles that do not penetrate or are placed away from the points).
In brief, and with caution:
- Chronic pain. This is the area with the strongest evidence. Large reviews and meta-analyses suggest that acupuncture provides greater relief than no treatment and somewhat greater relief than sham acupuncture for chronic low back pain, neck pain, knee osteoarthritis and headaches. The difference compared with sham is usually modest, which indicates that part of the benefit is due to nonspecific effects (expectation, context, attention received).
- Nausea and vomiting. Systematic reviews, including those by the Cochrane Collaboration, suggest that stimulating the Neiguan point (内关, nèiguān, PC6), on the inner side of the wrist, may reduce postoperative nausea. It has also been studied for chemotherapy-associated nausea.
- Clinical guidelines. The UK's NICE NG193 guideline (2021) on chronic primary pain considers offering a single course of acupuncture to adults with this type of pain, under certain cost and organizational conditions. At the same time, NICE does not recommend acupuncture for other forms of chronic pain in that guideline.
- Other uses. For many indications (infertility, weight loss, smoking, various chronic diseases) the evidence is limited, contradictory or of low quality, and does not allow a benefit to be claimed.
As for the mechanism, neurophysiological explanations have been proposed (release of endogenous opioids, modulation of pain signaling in the spinal cord and brain), but none is fully established. If you want to go deeper, see our page on scientific evidence in Chinese medicine.
Safety and precautions
When practiced by trained professionals with sterile, single-use equipment, acupuncture has few serious adverse effects. The most common mild effects are small bruises, pinpoint bleeding, soreness in the area or feeling dizzy during the session.
Serious risks are rare, but they exist:
- Pneumothorax from deep needling in the chest or upper back.
- Infections when hygiene standards are not followed or needles are reused.
- Injuries to nerves or blood vessels from poor technique.
Practical precautions:
- Tell the practitioner if you take anticoagulants or have a bleeding disorder.
- Tell them if you are pregnant, if you have a pacemaker (especially before electroacupuncture) or if you have skin problems in the area.
- Check that the needles are opened in front of you and discarded afterward.
- Do not stop or delay a medical treatment by replacing it with acupuncture, and discuss any new or persistent symptom with your doctor.
You will find more general information in our guide to safety in Chinese medicine.
Frequently asked questions
Does acupuncture hurt?
Acupuncture needles are much thinner than those used for injections, so insertion usually feels like a brief or almost imperceptible prick. Afterward it is common to feel heaviness, tingling or a dull sensation around the point, which tradition calls de qi. If you feel intense or sharp pain, tell the practitioner so they can adjust or remove the needle.
How many acupuncture sessions are needed?
There is no universal number. Clinical trials on chronic pain usually use courses of several weekly sessions, often between six and twelve. The sensible approach is to agree with the practitioner on a limited number of sessions, assess the response at the end, and not prolong treatment indefinitely if there is no clear and sustained improvement.
Does acupuncture help you quit smoking or lose weight?
The available evidence does not support claiming that acupuncture is effective for quitting smoking or for lasting weight loss. The studies are generally small and of limited quality, and the results are not clearly different from those obtained with sham acupuncture. For these goals there are treatments with better-demonstrated efficacy that are worth discussing with a health professional.
Is acupuncture safe during pregnancy?
It can be used during pregnancy, but only with practitioners who have specific experience, because tradition advises against stimulating certain points during pregnancy. It is essential to report the pregnancy before the session and to keep up with routine obstetric care. If any warning sign appears, such as bleeding or abdominal pain, the priority is to seek medical care.
Health notice. This content is educational and describes concepts of Traditional Chinese Medicine together with the available scientific evidence. It does not replace diagnosis or treatment by a healthcare professional. If symptoms are persistent or severe, consult your doctor. Safety guide.
