Acupuncture has been part of the medical mainstream in countries such as China and Japan for centuries. It is also one of the most widely utilized forms of alternative therapy in the United States. More than 10 million acupuncture treatments are administered annually in the U.S. alone. In addition, third-party insurance reimbursement and managed care coverage for acupuncture are increasing.

Due to its popularity, scientific investigation of acupuncture has grown dramatically in recent years, with many new studies reported every week. However, the results have been mixed at best.

What Is Acupuncture?

Simply defined, acupuncture is a treatment method aimed at eliciting a response (such as pain relief) through insertion of very fine needles at the body surface at sites called acupuncture points. A related technique called acupressure (or shiatsu) uses pressure on these points; a related therapy known as electroacupuncture applies electricity to the points.

A wide variety of treatment methods, approaches, techniques, styles, and theoretical frameworks exist within the very broad scope of the term acupuncture. Differences in forms of acupuncture are often cultural; the system of acupuncture practiced in Japan, for example, is quite different from that found in China. Many acupuncturists practice a more or less traditional style called Traditional Chinese Medicine (TCM). Others have adopted modern styles that have little or no reliance on traditional principles.

Acupuncture needles are most often inserted at specific locations on the skin called acupuncture points. These points are located on specific lines outlined by tradition, referred to as meridians or channels. According to Chinese medical theory, there are 14 major meridians that form an invisible network connecting the body surface with the internal organs. Meridians are to conduct Qi, the energy or vital force of the body. Pain or illness is said to result from imbalances or blockages in the flow of Qi through the meridians. Acupuncture is traditionally thought to remove such blockages, restore the normal circulation of Qi, and improve overall health by promoting the balance of energy in the system. However, there is no scientific evidence for the existence of the meridians or Qi itself. (Meridians are not visible under a microscope and, contrary to popular belief, they do not match major nerve pathways.)

In addition to meridians and Qi, the concept of yin and yang is central to acupuncture theory, as it is to all of traditional Chinese philosophy. The terms yin and yang do not represent forces or substances; rather, they are a way to look at the world in terms of the interaction of polar opposites. According to this viewpoint, all movement, growth, and change in the world is a manifestation of the push and pull of these forces. Although seemingly in opposition, these forces are thought to complement and support each other. For example, without rest one cannot exert energy; without becoming tired by exerting energy, it is difficult to sleep. This is just one illustration of the harmony and interaction of yin and yang.

Yang is traditionally associated with heat, power, daylight, summer, and many other active or energetic aspects of life; yin is cold, quiet, and dark. Many illnesses are characterized in terms of an excess or deficiency of either yin or yang, or of both at the same time. For example, when the body is feverish, it is too yang as a whole. There is also a yin and yang balance in each individual organ and part of the body; these can become excessive or deficient, too.

Thus, in TCM, illnesses are described as complex patterns of imbalances and blockages. Treatment is based not on medical diagnosis, but on identifying these problems in the body's energy and seeking to correct them. Does this traditional analysis contain truths about human health, or is it just archaic thinking? The answer, as yet, remains unknown.

History of Acupuncture

Primitive acupuncture needles dating back to around 1000 B.C. have been discovered in archeological finds of the Shan dynasty in China. The theoretical framework underlying the practice of acupuncture was first set forth in the Inner Classic of Medicine or Nei Jing, first published in 206 B.C. during the Han dynasty.

As an active and growing tradition, the theory and practice of TCM evolved over the centuries, at times undergoing rapid changes. Acupuncture reached perhaps its golden age under the Ming dynasty in the late 16th and early 17th centuries. Subsequently, it took second place to an ascending practice of herbal medicine. By the time acupuncture came back in vogue in 20th-century China, it had undergone a major transformation sometimes called the “herbalization of acupuncture.� Current acupuncture methods given the name Traditional Chinese Medicine are derived to a great extent from this relatively modern revision of the theory. Present-day Japanese acupuncture, however, dates back to earlier versions of acupuncture.

Another major change occurred after the Communist Revolution in 1949. The new leadership, while wanting to carry through a process of modernization, decided to support and preserve traditional medicine. During the Cultural Revolution, the famous "barefoot doctors" were trained in both modern and traditional medicine and sent out to the rural areas to provide medical care for the masses. Today, in the largest and most modern Chinese hospitals, Western medicine and TCM, including acupuncture and herbal treatments, are practiced side by side.

Acupuncture was virtually unheard of and unavailable in the U.S. until 1972, when President Nixon made his historic visit to China. Among the accompanying press was the well-known journalist James Reston, who was hospitalized while in China and received acupuncture anesthesia. Upon returning to the U.S., Reston published an article about his experience, stimulating new interest in acupuncture among the public and the medical community. Although it was later discovered that the drugs used along with acupuncture anesthesia probably played a major role, the perception of acupuncture as a powerful treatment caused it to gain respect in the U.S. Acupuncture schools began to open in the late 1970s and 1980s. With training available in the United States, the number of acupuncturists in this country began to grow rapidly, and today there are many thousands of certified and/or licensed acupuncturists.

How Does Acupuncture Work?

The exact mechanisms by which acupuncture might produce effects on the body remain unknown. Weak preliminary evidence from the 1970s hints that acupuncture encourages the release of endorphins (morphine-like compounds that function as the body's internal pain-regulating substances).1 Support for this theory comes from a study in which use of the drug naloxone, which opposes the effects of endorphins, was found to block pain relief from acupuncture.2 However, the body releases endorphins in response to any sort of pain, and it may be that it is needle-insertion per se, and not acupuncture, that is responsible for the rise in endorphins. Furthermore, there is some evidence that the placebo effect itself works by means of endorphins—in one study, naloxone blocked the ability of a placebo treatment to reduce pain.144

It has also been proposed that acupuncture may influence other chemicals in the body that control various physiologic activities. Preliminary studies have shown possible effects of acupuncture on norepinephrine, acetylcholine, and cyclic AMP, all of which are "chemical messengers" that regulate key systems in the body.4 However, none of this evidence is strong.

What Is the Scientific Evidence for Acupuncture?

Although there have been numerous controlled studies of acupuncture, there is no condition for which acupuncture's supporting evidence is strong. There are several reasons for this, but one is fundamental: even with the best of intentions, it is difficult to properly ascertain the effectiveness of a hands-on therapy such as acupuncture.

Only one form of study can truly prove that a treatment is effective: the double-blind, placebo-controlled trial. However, it isn’t easy to fit acupuncture into a study design of this type. One problem is designing a form of placebo acupuncture, and an even more challenging problem is to keep participants and practitioners in the dark regarding who is receiving real acupuncture and who is receiving fake. But without such blinding, the results of the study can be skewed by numerous factors. For a discussion of these factors, see Why Does The Natural Pharmacist Rely on Double-blind Studies?

In an attempt to approximate double-blind studies of acupuncture, researchers have resorted to a number of clever techniques. Perhaps the most common involves sham acupuncture. In such studies, a fake version of acupuncture is used to keep participants in the dark. However, because the acupuncturist knows that this is a fake treatment, he or she may subtly convey a lack of confidence in the outcome. Such studies are called single-blind and are not fully trustworthy. (The only exception are studies in which the patient is anesthetized prior to the acupuncture, and is therefore, presumably, incapable of receiving this sort of "top spin.")

To get around this problem and produce a truly double-blind study, some studies may employ technicians trained only to insert needles, rather than real acupuncturists. Such technicians might be given a list of real acupuncture points or phony acupuncture points, without being told which is which. However, it is not reasonable to suppose that an essentially untrained technician can give an acupuncture treatment as effective as that of a real acupuncturist. Furthermore, using a fixed set of points to treat a problem is not true to traditional acupuncture, which always individualizes treatment to the person.

Another approach is to use real acupuncturists to deliver treatment, but to have a separate person evaluate the effects of that treatment. Such studies may be described as partially double-blind (or "observer blind"); they prevent researchers from biasing their own observations, but they still don't eliminate the problem that the acupuncturist might communicate confidence (or lack of it) to the participants. Osteopathic physician Kerry Kamer suggested a whimsical approach to testing acupuncture: have half the participants receive real acupuncture, and the other half receive treatment from an actor trained to convey confidence while performing fake acupuncture. However, such studies have not yet been reported.

Despite their limitations, most of the best studies available at present are the single-blind or partially double-blind designs described earlier. Although imperfect, they at least can give us some idea whether true acupuncture might be effective.

There is another problem to consider as well: acupuncture causes a very strong placebo effect, whether it’s real or fake. This phenomenon tends to diminish the difference in results between the treatment group and the placebo group, and can potentially hide a true benefit by making it too small to reach statistical significance. As an example, consider a study in which 67 people with hip arthritis received either random needle placement or actual acupuncture.118 The results showed improvement in both groups, but to the same extent. Does this mean that traditional acupuncture is actually no better than random acupuncture? Not necessarily. The study could simply have been too small to identify benefits that did occur. In studies that show a strong placebo effect, it may be necessary to enroll hundreds of participants to show benefit above statistical “background noise.� Keep this in mind regarding all of the negative trials described below. A small study can fail to find benefit, but it cannot actually prove lack of benefit.

There is one additional problem in evaluating the evidence for acupuncture: many of the studies were performed in China, and there is evidence of systematic bias in the Chinese medical literature.5 Researchers evaluating the acupuncture studies from China discovered that every one found acupuncture effective! This led them to look further into other Chinese medical research. Upon review of controlled trials involving other therapies such as standard drugs, it was noted that Chinese trials reported positive results 99% of the time. By comparison, trials published in England were positive only 85% of the time. Although some bias exists in all medical publications, this finding suggests a particularly high rate of bias in the Chinese research record.

Some studies have compared acupuncture to other therapies, such as physical therapy or massage. Trials of this kind are good for determining relative cost effectiveness, but they can't be taken as proof of efficacy for one simple reason: these other therapies have never been proven effective themselves.

Numerous acupuncture studies failed to use placebo treatment or had no control group at all. Such studies prove nothing and generally are not reported here.

The following sections begin with conditions in which acupuncture research has been most positive, continue with those for which the record is mixed, and conclude with those in which the tested form of acupuncture has not proved effective. Note that we also include studies of acupressure and electroacupuncture.

Evidence-based Uses

Nausea and Vomiting

Numerous studies have evaluated treatment on a single acupuncture point—P6—traditionally thought to be effective for relief of various forms of nausea and vomiting. This point is located on the inside of the forearm, about 2 inches above the wrist crease. Most studies have investigated the effects of pressure on this point (acupressure) rather than needling. The most common methods involve a wristband with a pearl-sized bead in it situated over P6. The band exerts pressure on the bead while it is worn, and the user can press on the bead for extra stimulation.

Although the research record is mixed, on balance it appears that P6 stimulation offers at least modest benefits for nausea. This approach has been studied in anesthesia-induced nausea, the nausea and vomiting of pregnancy, and other forms of nausea.