Acupuncture helps to prevent headaches including migraines but faked procedures, in which needles are incorrectly inserted, can be equally effective, two reviews suggest.

In Wednesday's Cochrane Review journal, researchers in Germany reported on two separate reviews of 33 studies involving more than 6,700 people to see how well acupuncture prevented headaches and migraines.

"Much of the clinical benefit of acupuncture might be due to non-specific needling effects and powerful placebo effects, meaning selection of specific needle points may be less important than many practitioners have traditionally argued," said Klaus Linde, a complementary medicine researcher who led the reviews.

People with migraines suffer from attacks of mostly one-sided, severe headaches that can cause nausea, vomiting and a sensitivity to light, sound and smells.

Acupuncture is a therapy that involves inserting thin needles into the skin at certain pressure points, based on a theory of how energy runs through our bodies.

The therapy is used to reduce the frequency and intensity of migraine attacks, although a previous review suggested there wasn't enough evidence to support the use of acupuncture to prevent the headaches.

Long-term effects unknown

"Available studies suggest that acupuncture is at least as effective as, or possibly more effective than, prophylactic drug treatment, and has fewer adverse effects," the reviewers concluded.

"Acupuncture should be considered a treatment option for patients willing to undergo this treatment."

In the tension headache study, people treated with at least eight weeks of acupuncture suffered fewer headaches compared with those who used only pain killers, the researchers found.

Tension-type headaches affect both sides of the head, are mild to moderate in intensity, and have a pressing or tightening feel. The headaches do not get worse with routine physical activity, the study's authors said.

Half of those who received true acupuncture for the less severe headaches reported a decrease in the number of headache days by at least 50 per cent, compared with 41 per cent of those receiving "fake" acupuncture, in which needles were stuck in randomly.

More research is needed to learn how long the benefits of acupuncture last and whether better training would improve results, Linde said.

The reviews included trials in which some of the reviewers were involved, and some authors received fees for teaching acupuncture or speaking about acupuncture research.