Does cupping have medical benefits?

Question

Recently, in the Rio Olympics 2016, quite a few sportsmen and sportswomen have been seen with cupping marks, which allegedly result from the traditional Chinese/Oriental medicine treatment Hijama or potentially an alternative cupping method. A prominent example is Michael Phelps:

There has been a bit of a hype concerning the topic due to the popularity of the sportsmen, resulting in famous people speaking in and out of favour of the treatment. E.g. Penn and Teller linked to a blog post that seems to argue quite strongly against the treatment.

Now I am personally don't give alternative medicine much attention, since in a few cases (like accupuncture) it is quite well documented that the medical effect is mostly placebo. And it is simply not worth the effort fact checking every single one of these obscure methods.

However in this case I have a priori doubts if this is a purely traditional medicine treatment. There seem to be several forms of the treatment. This is also why I think there is room for expansion on this question: Does Hijama (cupping) alleviate pain and other ailments?.

E.g. I have been treated myself with a medical massage cupping by a German orthopedist as part of a posture treatment (as a scientist, unfortunately I sit down too much in weird positions in the lab). While I haven't looked into the evidence for its effectiveness, it has most certainly nothing to do with releasing blood or making the energy flow. The explanation I have been given is that the treatment simply loosens the connection between the fascia and the muscles. Of course this may be as much pseudo-science as the traditional treatments, intuitively it does sound more reasonable however. Hence the question:

Does cupping have medical benefits?

The different methods should be distinguished in an answer. The Hijama in particular is probably already resolved by the linked question.

Answer 1

Most of what I will repeat here comes from a blogger that goes by the moniker of Skeptical Raptor. In particular, his looking into the research. In his article, he cites two main sources (which unfortunately, some of us probably don't have access to depending on web settings):

• Huang CY, Choong MY, Li TS. Effectiveness of cupping therapy for low back pain: a systematic review. Acupunct Med. 2013 Sep;31(3):336-7. doi: 10.1136/acupmed-2013-010385. Epub 2013 Jul 25. Review. PubMed PMID: 23886511.

• Kim JI, Kim TH, Lee MS, Kang JW, Kim KH, Choi JY, Kang KW, Kim AR, Shin MS, Jung SY, Choi SM. Evaluation of wet-cupping therapy for persistent non-specific low back pain: a randomised, waiting-list controlled, open-label, parallel-group pilot trial. Trials. 2011 Jun 10;12:146. doi: 10.1186/1745-6215-12-146. PubMed PMID: 21663617; PubMed Central PMCID: PMC3141528.

The first critique is that traditional adherents to cupping talk about the body's qi... Whatever you may believe about cupping, let's dispense with the idea of qi. It's quackery and simply doesn't exist. Simon Singh and Edzard Ernst state in Trick or Treatment: The Undeniable Facts about Alternative Medicine

Scientists are still unable to find a shred of evidence to support the existence of meridians or Ch’i. The traditional principles of acupuncture are deeply flawed, as there is no evidence at all to demonstrate the existence of Ch’i or meridians. Acupuncture points and meridians are not a reality, but merely the product of an ancient Chinese philosophy.

According to Mark Crislip, cupping is “like most pseudo-medicine, it is an elaborate placebo with no real effects on real disease.”

Edzard Ernst, one of the leading scientists in debunking junk medicine, has stated:

In conclusion, this overview of SRs (systematic reviews) suggests that cupping may be effective for reducing pain. The evidence is insufficient for other indications. All SRs are based on primary studies with a high risk of bias. Therefore, considerable uncertainty remains about the therapeutic value of cupping.

Thank you to Jan Doggen for the Skpetoid link. That also gives some great gems regarding cupping. One telling thing is in the quote below (emphasis mine):

I searched and searched for any clinical trials of cupping as a treatment for any disease, but there simply aren't any. There is a large number of published articles in alternative medicine journals, nearly all from China, but none that come from any legitimate peer-reviewed journals. Part of the problem is that there is no specific condition that cupping is alleged to treat; even the Chinese articles are all over the map

Of course, there will be tons and tons of anecdotes as to why cupping works, and Brian does also address that (again, emphasis mine):

However, there's one very good reason that probably explains cupping's popularity in the modern world, despite its lack of any credible value. Modern cupping practitioners usually sell the service along with a massage, often both before and after the cupping procedure. Massage is extremely relaxing. It feels great and is a proven treatment for stress, anxiety, plus any number of muscular injuries and other pains.

Moreover, massage actually has a mechanism by which it provides relief. Popular research performed at McMaster University in Canada and published in 2012 analyzed samples of muscle tissue both before and after brutal, tissue-damaging exercise, and compared muscles that underwent therapeutic massage with muscles that did not. The analysis provided the mechanism and underscored what physical therapists and massage therapists have known for decades, that massage significantly improves the healing of muscle.

I think this quote from Skeptical Raptor sums it up best though:

Michael Phelps wins gold medals because he’s a freak athlete who trains at a level that is beyond my imagination. He doesn’t win those medals because he has a worthless and pseudoscientific procedure done to him. I don’t care what he says about cupping, it’s an anecdote at best.