But this study included what's called a passive control group - a group that did not receive any treatment at all. That makes it hard to determine whether the perceived benefits of cupping could result from a placebo effect, the researchers said. (A placebo effect is one that results from people's feeling that the treatment works, rather than any physiological effect of the treatment.) The researchers called for more studies to compare the effectiveness of cupping therapy with placebo treatments.
To tease out whether a therapy's benefits result from a placebo effect, researchers sometimes try to "blind" their subjects, meaning the participants don't know whether they are receiving a given treatment. But with cupping therapy, this is difficult because the therapy can leave marks, according to the 2011 study. Some researchers have tried to get around this problem by providing a "sham" treatment, which is similar to the real treatment but is done in a way that should not provide benefit.
In a 2015 study, researchers from Germany tested whether cupping therapy worked better than a sham treatment for patients with fibromyalgia, a chronic disorder that causes widespread pain, tenderness and muscle stiffness. Both the real treatment and the sham treatment used the same type of cups, but with the sham treatment, the cups had a hole at the top so that they couldn't create the proper suction. (Patients in the study were told they would receive either traditional cupping or "soft cupping," but they were not told that the so-called soft cupping was a sham treatment.)
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Most patients in the study correctly guessed whether they'd been given the traditional cupping or the soft cupping. Patients in both groups experienced about the same reductions in pain, which suggests "the effects of cupping therapy might be confounded" by effects that are not specific to the treatment itself, the researchers said.
Regardless of whether cupping therapy's perceived benefits result from a physiological effect or a placebo effect, the therapy could still be useful for some people, Bauer said. "If that's the treatment that gives me benefit ... if that's the time that I reduce my suffering [with this therapy] ... then I think we have to be a little more open to the idea of allowing patients some choice," as long as the therapy is safe, Bauer said.
Harmful effects from cupping therapy are rare, Bauer said. In one study of cupping, some patients reported a tingling sensation in their hands and arms, strain or pain in the treated area, and slight headache and tiredness, but none of the effects lasted longer than four hours. In some cases, people may develop infections over bruised skin, but the risk is small, Bauer said.
Original article on Live Science.