Thanks to Michael Phelps’s public display of cupping back at the Olympics in 2016, you’ve probably heard of the ancient Chinese therapy that leaves those infamous red circles on your back. And ever since then, more and more celebs have been showing off their alternative medicine battle wounds too (we’re looking at you, Kaley Cuoco). But what exactly is this whole cupping thing—and should you try it yourself?

Cupping: A Brief History

First things first, cupping therapy may be so-called “trendy” right now, but it is certainly not a trend. “It’s been used in many cultures around the world for possibly 5,000 years,” says cupping practitioner Frances Wocicki, MS, founder of Crow Heart Acupuncture & Chinese Herbs in Oakland, CA.

Evidence of cupping as a practice has been documented in early Chinese and Egyptian medicine. Historically, the first cups in China were made from animal horns and used to extract puss (blech). But these days, the cups—which are made from glass, plastic, silicone, or even copper—are thankfully not used to extract puss (sorry, we said it again) but to create a suction that draws blood to that area of the body.

To do this, when you go for cupping, a practitioner places multiple jars on your skin and either keeps them there or moves them around with oil. “It’s basically like a reverse massage, in that with a massage you are pushing the skin around, whereas, with cupping, you are pulling the skin up,” says Iman Majd, M.D., licensed acupuncturist and director of the Osher Clinic for Integrative Medicine at the University of Washington.

But don’t worry: Although the process sounds like it could be painful, you’ll actually likely enjoy it—with one exception. “Most patients actually find cupping really relaxing and soothing,” Majd says. “It’s not a painful treatment, but if their muscles are tight in a certain area, there could be some discomfort for one to two sessions,” he says.

The suction that the cups create increases blood flow to that particular region, which can loosen your muscles, relieve muscle tension, and can help reduce inflammation, Wocicki says.

“In Chinese medicine, there is a saying that ‘stagnation equals pain,'” she continues. Cupping aims to alleviate that pain by getting rid of the stagnation that may cause it in the first place. Blood contains nutrients and oxygen that help pick up toxins and waste products, so by increasing your blood flow to various parts of your body, you are increasing its ability to repair any damage that has been caused along the way.

“When you get rid of the ‘stagnation,’ you get rid of the pain by bringing this healing fluid—your blood—into the tissues,” Wocicki says.

When Do People Actually Use Cupping?

Most people don’t go for cupping just because. Rather, they usually go to treat something that ails them, whether it’s muscular pain and weakness, sports injuries, gastrointestinal and circulatory issues, lung ailments like a cough, skin troubles, or even stress.

Just like acupuncture, cupping doesn’t require a physician’s referral (unless your health insurance requires it), but Mark Carter, M.D., an internist and founder of Zero to Healthy, says it’s something a lot of M.D.s are trained in. “I’d recommend it to someone with muscle tension issues, problems relaxing certain muscles, or limited range of motion.”

And the actual number of cupping sessions depends on the case. “In some cases, I’ve done one to two treatments, and the issue has been resolved, but for others, it could take six to seven sessions. It all depends on the condition, how active the person is, and how chronic the condition is,” Majd says, adding that “the sooner we start the treatment, the faster we get results.”

Majd explains the whole process by telling patients to think of their muscles as a steak and their muscles’ layers as a Ziplock bag covering the steak. “When you put a steak in a Ziplock bag in the freezer, ultimately, the bag will get stuck on the steak, and it won’t move—which is where cupping comes in. Cupping ultimately pulls away the covering of the muscle—i.e., the Ziplock bag—so that your muscles can loosen up and move,” he says. And that’s when the blood flows.

The Acupuncture Addition

Another important thing to know about cupping is that it usually does not end with just cupping. Most patients who go for cupping get acupuncture too—and that’s because cupping is only part of the full story.

“A traditional medicine approach usually aims to treat both the branch—often the physical symptoms—and the root of the problem. In this way, cupping can be thought of as the branch, whereas acupuncture is the root,” Wocicki says. Cupping addresses the muscular pain on a local level, but acupuncture, which releases endorphins, may be better able to address the deeper, more systemic issues in the body, helping to encourage healing at the root level, Wocicki says.

“I almost always use acupuncture if I’m doing a cupping treatment, but I don’t always do cupping if I’m doing acupuncture,” she says. In fact, Majd says that most qualified cupping practitioners are actually acupuncturists first—so to get the best and safest cupping procedure, you’ll want to look for a qualified acupuncturist to do the job.

So, Is Cupping for You?

If you feel pain in your body or have issues elsewhere (skin, digestion), Carter suggests that it might be worth a shot. “Cupping is reportedly low risk, so there’s minimal downside if someone wants to try it,” he says. And although it looks like it might, Majd says there isn’t any data that it causes clots.

That said, there are still some limitations. Pregnant women should not be cupped on their abdomens or upper parts of their leg. People with high fevers or convulsions should also not be cupped. And cups should never be applied over areas of broken bones, fractures, ruptured tendons, or injuries that involved bleeding.

“I would also not cup a patient with a bleeding disorder or anyone in a fragile medical state in general,” Wocicki says. And if you have a history of deep vein thrombosis (DVT) in your legs—which is essentially a blood clot in a deep vein—it’s also best to avoid those areas too, to make sure that the clots will not get dislodged, Majd says.

Also, keep in mind: You will have those infamous cupping bruises for a while. How long depends on how dark the mark is, which varies depending on the person (and, importantly, isn’t an indication of how strong the process was).

“Someone with a healthy blood flow and not a lot of stagnation will tend to have lighter marks from the cupping than someone with more stagnation,” Wocicki says. Lighter marks tend to disappear more quickly—maybe around a day or two—whereas darker marks can last longer, for a week or more, and fade slowly with time.

In the end, of course, the decision to give it a go is yours. But one thing is for sure: Cupping is definitely on the up and up, so if you are feeling some sort of physical pain, it couldn’t hurt to check in with a practitioner to see if the treatment could be helpful for you.

Annie Daly is a freelance writer and editor based in Brooklyn Heights, New York. You can follow her on Instagram and Twitter at @anniemdaly, and find more of her work on her website,