Scientists derided research published on Tuesday that suggested ear acupuncture may help people lose weight, saying the study's design was flawed and its conclusions highly implausible.
Responding to the findings of research published online in the journal Acupuncture in Medicine, experts not involved in the work said it was unreliable and probably a waste of money.
"It is hard to think of a treatment that is less plausible than ear acupuncture," said Edzard Ernst, a professor of complementary medicine at Britain's University of Exeter.
A summary statement about the study, conducted by Korean researchers, said it compared three approaches in a total of 91 people - acupuncture on five points on the outer ear, acupuncture on one point, and a sham treatment as a control.
It said participants were asked to follow a restrictive diet, but not one designed to lead to weight loss, and not to take any extra exercise during eight weeks of treatment.
Its results suggested significant differences were apparent after four weeks, with the active treatment groups receiving acupuncture on one or five points having lower body mass index scores compared with the sham treatment group, where there was no such reduction.
Weight also differed significantly after four weeks in both active treatment groups compared with the sham treatment group, the researchers reported in the journal, which is one of 50 specialist titles published by British Medical Journal group.
According to background information given in the journal, auricular acupuncture therapy is based on the understanding that the outer ear represents all parts of the body and was first used in France in 1956 by a doctor who noticed that a patient's back-ache was cured after a burn on the ear.
But external experts said this research and its apparent conclusions should be viewed with extreme caution.
"While it's good to see attempts to evaluate so-called alternative treatments using the same approach as is used for more conventional treatments, this study has several features that complicate the picture," said Kevin McConway, a professor of applied statistics at Open University.
He noted that more than a third of the study's small number of starting participants did not complete the course, and yet the main results did not take this into account.
"The study lasted only eight weeks, which is not long when it comes to a long-term issue like being overweight," he said.
"It tells us nothing about what might happen after eight weeks, and the world is full of weight-loss treatments that have no demonstrable longer-term effect".
Ernst, whose research at Exeter evaluates scientific evidence for acupuncture, homeopathy, herbal medicine, and other alternative therapies, said the trial had "several serious flaws". He too pointed to its small sample size and high drop-out rate, as well as what he called "questionable statistics".
"Collectively, these limitations render the findings far too unreliable for issuing recommendations about the use of ear acupuncture," he said. "Consulting an acupuncturist will reduce your cash but not your body weight."