Why does anyone believe this works? The dangers of cupping.

Cupping therapy. If this looks painful and possibly damaging

to the skin, that's because it is.

People are easily fooled. Even smart people.

I'm not talking about voters in the U.S. and the UK, although both groups have recently demonstrated how easily they can be conned into voting against their own interests. You can read plenty of articles about that elsewhere.

No, I'm talking about the wide variety of health treatments that call themselves alternative medicine, integrative medicine, traditional Chinese medicine, energy medicine, and other names. These are all just marketing terms, but many people, including some physicians and scientists, seem captivated by them.

This week I'm going to look at "cupping," a rather bizarre treatment that, for reasons that escape me, seems to be growing in popularity.

I just returned from a scientific conference, where I happened to speak with an editor for a major scientific journal who also follows this blog. She remarked that she liked some of my articles, but she disagreed with me about cupping, which I wrote about during the 2016 Olympics, where swimmer Michael Phelps was observed to have the circular welts that are after-effects of cupping. This editor's argument boiled down to "it works for me," which left me somewhat flabbergasted.

And just two weeks ago, when I was at my physical therapist's office getting treatment for a shoulder injury, I heard her discussing cupping with another therapist. I then noticed a large box containing cupping equipment on one of the counters. Thankfully, my therapist didn't suggest cupping for me; I'm not sure how I would have replied.

What is cupping? It's a technique where you take glass cups, heat the air inside them, and then place them on the skin. Because hot air is less dense, it creates suction as it cools, which sucks your skin up into the glass. (Some cupping sets use pumps rather than heat to create this effect.) Imagine someone giving you a massive hickey, and then doing another dozen or so all over your back, or legs, or wherever the cupping therapist thinks you need it. If that sounds kind of gross, it is.

Quacktitioners Practitioners of cupping think that it somehow corrects your "qi," a mysterious life force that simply doesn't exist. When pressed, they often remark that it "improves blood flow," a catch-all explanation that has no scientific basis and that is more or less meaningless. What really happens, as the physician and blogger Orac noted, is this:

"The suction from cupping breaks capillaries, which is why not infrequently there are bruises left in the shape of the cups afterward.... If you repeatedly injure the same area of skin over time ... by placing the cups in exactly the same place over and over again, the skin there can actually die."

So maybe cupping isn't so good for you.

Cupping is ridiculous. There's no scientific or medical evidence that it provides any benefit, and it clearly carries some risk of harm. A recent review in a journal dedicated to alternative medicine–one of the friendliest possible venues for this kind of pseudoscience–concluded that

"No explicit recommendation for or against the use of cupping for athletes can be made. More studies are necessary."

Right. That's what proponents of pseudoscience always say when the evidence fails to support their bogus claims. Let us do more studies, they argue, and eventually we'll prove what we already believe. That's a recipe for bad science.

Even NCCIH, the arm of NIH dedicated to studying complementary and integrative nonsense medicine, can't bring itself to endorse cupping. Their summary states:

• There’s been some research on cupping, but most of it is of low quality.
• Cupping may help reduce pain, but the evidence for this isn’t very strong.
• There’s not enough high-quality research to allow conclusions to be reached about whether cupping is helpful for other conditions.

In other words, some bad scientists have conducted a few studies but haven't proven anything. But wait, it gets worse. NCCIH goes on to warn that:

• Cupping can cause side effects such as persistent skin discoloration, scars, burns, and infections, and may worsen eczema or psoriasis. 
• Rare cases of severe side effects have been reported, such as bleeding inside the skull (after cupping on the scalp) and anemia from blood loss (after repeated wet cupping). 

And still, otherwise intelligent people say "it works for me." I'm left speechless.

The bottom line: save your money and your skin. Don't let anyone suck it into those cups.

Someone needs to tell Michael Phelps to stop bruising himself

It happens every four years. No, not the Olympics, though of course that happens too. I'm talking about new wackadoodle performance enhancement fads. In the 2008 and 2012 Olympics, it was magic tape, which we saw plastered across the arms and legs of many swimmers. This year it's "cupping," a crude technique that leaves nasty red or purple welts all over your body. Michael Phelps, one of the best male swimmers in Olympic history, featured these lovely welts in photos this week, and you can catch a glimpse of him getting the treatment in the UnderArmour "Rule Yourself" ad featuring Phelps (which is otherwise an excellent ad).

Phelps isn't the only one. Former Olympic swimmer Natalie Coughlin and gymnast Alex Naddour have displayed the distinctive circular welts too.

The New York Times, USA Today, and People all ran articles yesterday explaining what those nasty red bruises were all over Phelps' torso and shoulders. USA Today reported, unquestioningly, that athletes use cupping "to relieve tension in their muscles." The NY Times (from which we might expect a bit more skepticism) reported blithely that "Physiologically, cupping is thought to draw blood to the affected area, reducing soreness and speeding healing of overworked muscles." People used the same argument, and then added this bit of illogic:

"given that Phelps took home his 23rd Olympic medal last night, it's tough to argue."

No, it's not. Cupping is ridiculous. There's no scientific or medical evidence that it provides any benefit. The NY Times did express a bit of doubt (though not much), summarizing two small experiments that showed that cupping worked no better than placebo. But the Times couldn't help itself, and went back to quoting anecdotal evidence from true believers.

Rather than review the evidence here, I refer you to a thorough takedown of cupping written last month by Orac, a well-known science blogger who is also a surgeon:

"Among the silliest of alternative medicine therapies is something called cupping.... The suction from cupping breaks capillaries, which is why not infrequently there are bruises left in the shape of the cups afterward."

As Orac points out, repeated cupping in the same spot can destroy your skin and lead to dangerous infections. Another physician, Dr. Harriett Hall, in an article for Slate in 2012, made similar points.

I'm not sure who told Michael Phelps that cupping would help him swim faster, but I am sure that it's terrible advice–definitely not helpful and maybe harmful.

I know athletes are notoriously superstitious, and they get some psychological benefits from the various rituals they use to prepare for competition. There's no harm in believing that magic tape, or a lucky shirt, or always stepping onto the field with your left foot first–or whatever–will help you win. But Michael Phelps and his fellow Olympians should run as fast as possible from unproven treatments (and make no mistake, cupping is one of these) that can only cause them harm.