After acupuncture relieved her terrible menstrual cramps, Lori Lander Murphy immediately set up an appointment for her teenage daughter, who was searching for relief from daily migraines. “A few treatments and her headaches were suddenly less severe,” says Murphy, a writer and librarian from suburban Philadelphia. “I’m definitely sold on acupuncture.”

But does it really work, or is the relief all in your head? And which conditions is this ancient Chinese therapy best for?

While no one is really sure how acupuncture works, recent research suggests it influences the areas of the brain that affect pain perception. It also may boost the brain’s ability to recognize pain-easing chemicals made by the body. Some proponents believe (though this is not proven) that it works like massage and yoga do, helping to release tension in connective tissue so there is less pain and inflammation.

Studies on acupuncture suggest it may be helpful against these five conditions.

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Chronic pain conditions

“The strongest, most incontrovertible evidence is for chronic pain,” says Robert Davis, a licensed acupuncturist in Vermont and co-president of the Society for Acupuncture Research.

A 2012 analysis published in the Archives of Internal Medicine that looked at almost 20,000 patients from other studies found that acupuncture was better than sham, or fake, acupuncture treatment for conditions including chronic migraine headaches, knee osteoarthritis, and back, neck and shoulder pain.

One of the big advantages of treating pain with acupuncture, says Davis, is that acupuncture may pose fewer risks than certain medications. In those cases, he says, you may want to try acupuncture first to see if it works. “There’s lots of really strong evidence for acupuncture’s safety,” he says.

Carpel tunnel syndrome

The pain and numbness of carpal tunnel syndrome happen because the median nerve in the wrist becomes pinched. Acupuncture may help improve blood flow through the wrist, according to a 2013 Harvard Medical School study.

The study found that in people with carpal tunnel syndrome there was less blood flow to the fingers. But after the people received acupuncture, blood flow improved and the people reported less pain.

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Fibromyalgia

A 2014 Portuguese study on people with this generalized pain disorder found that acupuncture relieved pain in the immediate term in more than 94 percent of the study participants.

Brain scan evidence suggests that people with fibromyalgia who undergo acupuncture have more receptors for opioids. That might make them more responsive to opioid pain medications as well as the body’s own natural painkillers.

Mayo Clinic researchers found that acupuncture significantly helped with fatigue and anxiety as well as pain in 25 people with fibromyalgia. The patients still felt better at the seven-month follow-up.

Other studies have found acupuncture may raise the pain threshold in people with the condition.

Menstrual pain

In studies reviewed by the Cochrane Collaboration, an international not-for-profit organization that examines research results to assess how well treatments work, acupuncture outperformed drugs for relieving the pain of menstrual cramps. Bonus: It also lessened the nausea and back pain that sometimes accompany cramps.

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Nausea from morning sickness and chemotherapy

Using acupuncture on one point on the wrist may help ease the kind of severe morning sickness Princess Kate had, according to one study published in the Journal of Pain and Symptom Management.

Studies of acupuncture for chemotherapy-induced nausea have been largely positive and “convincing,” according to the National Cancer Institute.

Finding the right practitioner

To boost your chances of getting the most effective treatment, says Davis, make sure you go to an acupuncturist who is licensed. Licensing requirements vary from state to state. However, most acupuncturists have to pass a licensing exam prepared by the National Certification Commission for Acupuncture and Oriental Medicine (NCCAOM). To find a licensed acupuncturist near you, go to the NCCAOM website and click on “Find a practitioner.”

Many employer health plans cover acupuncture treatments.

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Denise Foley is a veteran health writer and a former contributing executive editor at Prevention magazine.