Unless you’ve been living underneath a rock, you’re aware that Michael Phelps has been tearing it up in the Olympic pool for what seems like the umpteenth time.  And chances are you’ve noticed that America’s favorite swimmer is covered in weird reddish purple circles. If you’re like most of us, you have no idea where they come from.

The answer is that Phelps, along with many of his teammates, has adopted the ancient Chinese practice of “cupping.”  The process involves placing a cup on the skin and then creating a vacuum that sucks the skin upwards.  The process often results in broken blood vessels, causing red marks.  The process is supposed to accelerate recovery and prevent future injury.

But does “cupping” really work?

Some authors who have reported on Phelps and cupping display a knee-jerk reaction to the procedure, categorizing it as a sham treatment.  Are these sceptics right?  There really hasn’t been a lot of research done on cupping therapy although that’s certain to change.  Additionally, the few studies that have been performed test the efficacy of cupping on different conditions: acne, chronic pain, and fibromyalgia that don’t really correlate with the effects Michael Phelps is after.

The best known study to measure the effects of cupping was conducted in 2015 by a team of German scientists.  The study looked at the efficacy of cupping for the treatment of fibromyalgia.   There were three main groups tested: a control group that received no cupping therapy, a group that received a “sham” cupping therapy, and a group that received cupping therapy.  The “sham” control had a cup applied to their skin, but a vacuum was never created.  The study concluded both cupping groups had more reduction in pain than the control group, but there was no difference in pain reduction between true cupping therapy and the sham cupping therapy.  The study suggests that the cupping treatment does not reduce pain reduction and any perceived effects could be explained by the placebo effect.

However, one study is not enough to reach a definitive conclusion about whether or not cupping really works.  Some other, less rigorous studies have concluded that cupping does in fact bring about a reduction in pain.  So does cupping really work? The jury’s still out.

As the scientific community investigates whether or cupping works, it is important to understand that Michael Phelps’s adoption of the treatment may not be a testament to its efficacy.  It seems unlikely that Michael Phelps has come across a life changing medical treatment that relies on heated cups to conquer chronic pain.  But, so as to not be hypocritical, it is important to wait for a real consensus before dismissing the treatment without hard evidence.  After all, Michael Phelps did seem to be swimming pretty well.