In August 2016, people watching the Rio Olympics noticed something odd on Michael Phelps’s shoulders: a row of dark purple circles. Some members of the US men’s gymnastics team had them too. Within days, newspapers around the world were explaining cupping to readers who had never heard of it.
Cupping itself is very old. Chinese medicine has used it for centuries, and the Science Museum in London holds a bronze cupping vessel from Pompeii, around two thousand years old, along with a cupping set made in London in the nineteenth century, when cupping still had a regular place in Western medicine. The Olympians brought an old treatment back into view. The interesting question is what the cups actually do.
How fire cupping works
In fire cupping, the practitioner holds a lit ball of alcohol-soaked cotton wool inside a glass cup for a second or two, takes it out, and places the cup on the skin. The flame heats the air inside the cup and drives some of it out. As the remaining air cools, the pressure inside drops and the cup grips. The flame never touches you.
The practitioner can leave the cups in place for several minutes, glide them slowly across oiled skin, or apply and lift them quickly one after another. All of these are forms of dry cupping, in which the skin stays intact. Wet cupping, which involves small cuts to draw blood, is a separate practice.
What happens beneath the skin
The suction pulls the skin and the layers beneath it up into the cup. A 2017 review in Complementary Therapies in Clinical Practice describes what follows: the negative pressure stretches the skin and the tissue underneath, and it widens the small blood vessels, which increases blood flow to the area. With enough suction for long enough, some of the smallest vessels, the capillaries, give way and release a little blood into the surrounding tissue. That blood creates the round marks.
The marks look dramatic, but nothing has struck or crushed the tissue, and most people feel little or nothing where they appear. They fade over several days to a week or so. Practitioners of Chinese medicine read their colour: a dark mark suggests more stagnation of Qi and Blood in that area, and a pale one less.
How this might ease pain or stiffness is less clear. A 2019 review in the Journal of Traditional and Complementary Medicine set out six different theories for how cupping works and concluded that no single one explains its effects. The authors called for more research to support or rule out each theory. The simplest explanation is mechanical. Massage and most hands-on treatments press into tissue, while cupping lifts and stretches it.
Why athletes use it
Elite athletes have access to almost every recovery method there is, so it makes sense that they would try cupping. Those who use it generally describe it as part of their recovery, a way to loosen muscles after hard training, and the marks seen in Rio sat mostly on the shoulders and back.
The research is thinner than the publicity. In 2018, a systematic review in the Journal of Alternative and Complementary Medicine gathered 11 randomised trials of cupping in amateur and professional athletes, with 498 participants between them. Several reported benefits for pain, disability and range of movement, mostly compared with no treatment at all. However, most of the trials had an unclear or high risk of bias, and none of them reported on safety. The authors could not recommend cupping for athletes either way, and they called for more studies.
The US National Center for Complementary and Integrative Health takes a similar view of cupping in general: it may help reduce pain, but the evidence for this is not very strong. Expectation and the experience of treatment probably play a part, as they do with many recovery methods in sport.
Put together, cupping produces real, visible changes in the skin and in local blood flow, many people enjoy how it feels, and the trials so far are too small and too flawed to say how much it helps.
What a session feels like
Cupping feels like a firm pull, a little strange for the first few seconds and then usually comfortable. Many people find it relaxing, particularly on the upper back and shoulders, where the broad muscles give the cups plenty of room to sit. Cups that stay in one place create a steady, drawing sensation. When the practitioner glides them over oiled skin, it feels more like a deep, slow massage.
Afterwards, the marks stay visible for a while. If you have an event coming up where your back or shoulders will be on show, plan your session around it.
Who should take care
Like any treatment, cupping carries some risk. The US National Center for Complementary and Integrative Health lists lasting skin discolouration, scars, burns and infection among the possible problems, and notes that cupping may worsen eczema or psoriasis. Before a session:
- Tell your practitioner if you take blood-thinning medication, bruise easily or have a bleeding disorder.
- Expect your practitioner to avoid broken, inflamed or sunburnt skin, varicose veins, and patches of eczema or psoriasis.
- Mention it if you are pregnant or might be.
- Let your GP, physiotherapist or anyone else treating you know about the cupping, so nobody mistakes the marks for an injury.
The marks that caught the world’s attention in Rio are the visible part of a simple physical process. If you try cupping, whether in Watford or anywhere else, choose a registered practitioner who asks about your health first and explains what the cups are for.