Michael Phelps and the Great Cupping Debate: Why the Olympic Gold Medalist May Actually Be Right

If you've been watching the 2016 Rio Olympics, you've probably heard about cupping. It's an ancient Chinese medical practice that uses small suction cups to bring blood to the skin, which adherents claim helps improve circulation and treat pain. It also tends to leave prominent hickey-like marks, as seen on swimming legend Michael Phelps and gymnast Alex Naddour.

But does cupping actually work? Or is it more akin to something ridiculous like ear candling? Like many "alternative" therapies, cupping hasn't been studied in a very thorough and well-designed way. Some early research, however, indicates that it may be helpful. A 2014 review in the Journal of Traditional Chinese Medical Sciences that analyzed 16 studies on the topic suggests that cupping reduces pain in the short-term "compared with no treatment, heat therapy, usual care, or conventional drugs."

Another study, conducted in March, used cupping on half of 60 patients with neck pain. It found that those who underwent the process reported significantly less pain than those who didn't. And one trial of the technique on people with arthritis in the knee reported a similar benefit.

A comprehensive 2012 review suggests it could have potential to treat pain as well as herpes zoster and other conditions. But it also found studies looking at cupping to be "generally of low methodological quality," and concluded that 84 percent of the 135 trials on the topic were at high risk of bias.

Despite the inconclusive evidence, some athletes swear by cupping. "I've done it before meets, pretty much every meet I go to," Phelps said at a press conference on August 8. Naddour told USA Today that cupping has "been the secret that I have had through this year that keeps me healthy," adding "it's been better than any money I've spent on anything else."

But don't trust those dumb athletes, right? That's what some media commentators seem to be suggesting. "Please, Michael Phelps, Stop Cupping," reads a headline in The Atlantic, in astory arguing that cupping "invites people to distrust science." ScienceBlogs had a similar take, with a post entitled "Thanks, Michael Phelps, for glamorizing cupping quackery!" Many others made similar arguments on Twitter.

Cupping could be nothing more than a placebo effect. Yet the reactions, which purport to be science-based, don't seem to look carefully at the research itself, which suggests some benefits to the practice. People seem to be dismissing cupping because, like acupuncture—which also hasn't been thoroughly studied, but shows promise in treating some conditions—it falls outside the purview of Western science.

It may be too soon to declare that cupping works, and it should be studied more. But it's also too soon to declare that cupping doesn't work. Either way, if performed by a skilled and trained practitioner, it seems unlikely to cause harm. Which means critics and non-athletes, especially those who have never tried cupping, perhaps should be less critical of Olympic medalists who say it helps.