Acupuncture is increasingly an evidence-based medicine. A search of google scholar or pubmed (a free archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health’s National Library of Medicine (NIH/NLM) will produce thousands of papers exploring the mechanism, outcomes and clinical efficacy of acupuncture interventions. These mostly take the form of randomised controlled trials (RCTs), systematic reviews and meta-analyses. The RCT is considered the gold standard for scientific research into medical treatments. The treatment being tested (in this case acupuncture) is called the experimental condition, and it is compared to a ‘control’ – which is generally ‘usual care’ or some form of placebo. In order that the clinical efficacy of treatment can be distinguished from the placebo effect, studies try to ensure that participants do not know which group they are in. This is much harder for acupuncture than it is for biomedical drugs.

It can be argued that the design of RCTs distorts the practice of acupuncture. Acupuncture is a multi-component intervention. On the other hand, RCTs need to simplify procedures – both to enable replication and to isolate experimental variables. Therefore, the treatment given in a research trial may not really reflect acupuncture as it is practised in clinic. Chinese medicine also involves a distinct process of diagnosis that does not always sit easily with biomedical categories. A group of patients suffering from ‘migraine’ for example, may receive different diagnoses from a Chinese medical perspective, and would not receive the same treatment in an acupuncture clinic.

In order for research results to be convincing, it is important to have an adequate number of participants. This can be challenging. Participants need to make a significant commitment to attend repeated treatments and follow up. Some trials will therefore likely be shorter than the optimal treatment duration and may be small in scale. Researchers may try to overcome the shortcomings of small trials by doing a ‘systematic review’ of multiple trials. This attempts to bring the results of RCTs together, thus increasing the size of the sample. However, this can be problematic where trials and participants are not directly comparable. Trials will apply different inclusion/exclusion criteria according to their specific research question. There are also many different styles and schools of acupuncture.

A meta-analysis is the statistical combination of the results of multiple studies. However, a meta-analysis is only as good as the data provided by the RCTs. Many statistical results involve the translation of the subjective experience of symptoms into numerical format. When the likely heterogeneity of included studies is taken into account, it is clear that these figures are unlikely to give a full and accurate picture.

Despite these limitations, research into acupuncture provides some valuable evidence that acupuncture is effective in addressing certain conditions. Details of some of this evidence is provided in subsequent sections.