The Rio Olympics passed with record-breaking feats and heart-melting moments, but some of us are still scratching our heads over those weird-looking welts that decorated several olympians, including U.S. swimmer Michael Phelps.

Cupping is the source of these marks, but the name doesn’t shed much light onto the purpose behind the practice. A flame heats the rims of special cups, or air is suctioned through the cups creating a vacuum when placed on a body. Pulling skin and blood vessels upward, the cups leave behind the signature purple circles that cuppers say will lead to increased blood flow. 

Cupping advocates also say that it soothes pain and inflammation, promoting relaxation and athletic performance. However, there’s technically no evidence that it actually does anything besides bruising people’s bodies. Bruises are blood clots, meaning that blood is not flowing. 

Recently, “Big Bang Theory” star Kaley Cuoco gave cupping a try, and she isn’t the first celebrity. Gwyneth Paltrow and Jennifer Aniston dabbled in cupping back in 2013. Ranging from $40-$80 a session, cupping is accessible to the Hollywood crowd, but is definitely a price jump from the bag of ice or aspirin that most people use.

While the practice dates back centuries to when the Chinese used horns to draw toxins out of snakebites, cupping hasn’t proved to be much more than a case of the placebo effect. Tricking the mind into improving the body’s health is useful, but some have taken to buying their own cups to use on themselves. Outside of a trained environment, people have suffered severe burns and blisters from the treatment.

If you want to avoid the risks, discomfort, and giant bruises, there are legitimate ways to find what cupping claims to offer. Regular stretching and deep tissue massages will lead to increased relaxation and athleticism. Staying hydrated and exercising will also promote blood flow. It may not be a trendy health fad, but proper diets and consistent workouts are what built olympians like Phelps, not questionable, ancient therapies.