Article Text

An exploratory review of the electroacupuncture literature: clinical applications and endorphin mechanisms
  1. David Mayor
  1. Department of Physiotherapy, University of Hertfordshire, Hertfordshire, UK
  1. Correspondence to David Mayor, 86 Handside Lane, Welwyn Garden City, Herts AL8 6SJ, UK; davidmayor{at}


Electroacupuncture (EA) is widely used in clinical practice and research, as well as in experimental investigations into the mechanisms of acupuncture. This study explores publication trends in clinical and experimental studies of EA (1975–2011) for pain and non-pain research; EA use for different clinical conditions (1974–2012); and the relation of EA research, including stimulation frequency, to opioid peptide mechanisms.

Appropriate PubMed ‘all fields’ searches were conducted, identified studies were classified using PubMed filters and manually, and data extracted into tables. A total of

2916 clinical studies were located, of which 19% involved EA. Additionally, 3344 animal studies were located, of which 48% involved EA. The publication rate of EA studies per year has risen over time, but the percentage of studies of pain has fallen from 60% to 25%. The conditions most commonly treated with EA are musculoskeletal, neurological, obstetric and gastrointestinal, along with intraoperative and postoperative analgesia. EA studies, particularly with low frequency stimulation, are more likely to support the role of endogenous opioid mechanisms than manual acupuncture studies, and opioid release is more likely in the central nervous system than the circulation.

EA is increasingly used in clinical and especially experimental research, particularly for non-pain conditions. Acupuncture does release endogenous opioids, but this probably depends on ‘dosage’, with the evidence more consistent and convincing for EA than for manual acupuncture. Different frequencies of EA appear to activate different endogenous opioid mechanisms.

Statistics from

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.