This piece is almost identical with today’s Spectator Health article.
This week there has been enormously wide coverage in the press for one of the worst papers on acupuncture that I’ve come across. As so often, the paper showed the opposite of what its title and press release, claimed. For another stunning example of this sleight of hand, try Acupuncturists show that acupuncture doesn’t work, but conclude the opposite: journal fails, published in the British Journal of General Practice).
Presumably the wide coverage was a result of the hyped-up press release issued by the journal, BMJ Acupuncture in Medicine. That is not the British Medical Journal of course, but it is, bafflingly, published by the BMJ Press group, and if you subscribe to press releases from the real BMJ. you also get them from Acupuncture in Medicine. The BMJ group should not be mixing up press releases about real medicine with press releases about quackery. There seems to be something about quackery that’s clickbait for the mainstream media.
As so often, the press release was shockingly misleading: It said
Acupuncture may alleviate babies’ excessive crying Needling twice weekly for 2 weeks reduced crying time significantly
This is totally untrue. Here’s why.
Luckily the Science Media Centre was on the case quickly: read their assessment.
The paper made the most elementary of all statistical mistakes. It failed to make allowance for the jelly bean problem.
The paper lists 24 different tests of statistical significance and focusses attention on three that happen to give a P value (just) less than 0.05, and so were declared to be "statistically significant". If you do enough tests, some are bound to come out “statistically significant” by chance. They are false postives, and the conclusions are as meaningless as “green jelly beans cause acne” in the cartoon. This is called P-hacking and it’s a well known cause of problems. It was evidently beyond the wit of the referees to notice this naive mistake. It’s very doubtful whether there is anything happening but random variability.
And that’s before you even get to the problem of the weakness of the evidence provided by P values close to 0.05. There’s at least a 30% chance of such values being false positives, even if it were not for the jelly bean problem, and a lot more than 30% if the hypothesis being tested is implausible. I leave it to the reader to assess the plausibility of the hypothesis that a good way to stop a baby crying is to stick needles into the poor baby.
One of the people asked for an opinion on the paper was George Lewith, the well-known apologist for all things quackish. He described the work as being a "good sized fastidious well conducted study ….. The outcome is clear". Thus showing an ignorance of statistics that would shame an undergraduate.
On the Today Programme, I was interviewed by the formidable John Humphrys, along with the mandatory member of the flat-earth society whom the BBC seems to feel obliged to invite along for "balance". In this case it was professional acupuncturist, Mike Cummings, who is an associate editor of the journal in which the paper appeared. Perhaps he’d read the Science media centre’s assessment before he came on, because he said, quite rightly, that
"in technical terms the study is negative" "the primary outcome did not turn out to be statistically significant"
to which Humphrys retorted, reasonably enough, “So it doesn’t work”. Cummings’ response to this was a lot of bluster about how unfair it was for NICE to expect a treatment to perform better than placebo. It was fascinating to hear Cummings admit that the press release by his own journal was simply wrong.
Listen to the interview here
Another obvious flaw of the study is that the nature of the control group. It is not stated very clearly but it seems that the baby was left alone with the acupuncturist for 10 minutes. A far better control would have been to have the baby cuddled by its mother, or by a nurse. That’s what was used by Olafsdottir et al (2001) in a study that showed cuddling worked just as well as another form of quackery, chiropractic, to stop babies crying.
Manufactured doubt is a potent weapon of the alternative medicine industry. It’s the same tactic as was used by the tobacco industry. You scrape together a few lousy papers like this one and use them to pretend that there’s a controversy. For years the tobacco industry used this tactic to try to persuade people that cigarettes didn’t give you cancer, and that nicotine wasn’t addictive. The main stream media obligingly invite the representatives of the industry who convey to the reader/listener that there is a controversy, when there isn’t.
Acupuncture is no longer controversial. It just doesn’t work -see Acupuncture is a theatrical placebo: the end of a myth. Try to imagine a pill that had been subjected to well over 3000 trials without anyone producing convincing evidence for a clinically useful effect. It would have been abandoned years ago. But by manufacturing doubt, the acupuncture industry has managed to keep its product in the news. Every paper on the subject ends with the words "more research is needed". No it isn’t.
Acupuncture is pre-scientific idea that was moribund everywhere, even in China, until it was revived by Mao Zedong as part of the appalling Great Proletarian Revolution. Now it is big business in China, and 100 percent of the clinical trials that come from China are positive.
if you believe them, you’ll truly believe anything.
29 January 2017
Soon after the Today programme in which we both appeared, the acupuncturist, Mike Cummings, posted his reaction to the programme. I thought it worth posting the original version in full. Its petulance and abusiveness are quite remarkable.
I thank Cummings for giving publicity to the video of our appearance, and for referring to my Wikipedia page. I leave it to the reader to judge my competence, and his, in the statistics of clinical trials. And it’s odd to be described as a "professional blogger" when the 400+ posts on dcscience.net don’t make a penny -in fact they cost me money. In contrast, he is the salaried medical director of the British Medical Acupuncture Society.
It’s very clear that he has no understanding of the error of the transposed conditional, nor even the mulltiple comparison problem (and neither, it seems, does he know the meaning of the word ‘protagonist’).
I ignored his piece, but several friends complained to the BMJ for allowing such abusive material on their blog site. As a result a few changes were made. The “baying mob” is still there, but the Wikipedia link has gone. I thought that readers might be interested to read the original unexpurgated version. It shows, better than I ever could, the weakness of the arguments of the alternative medicine community. To quote Upton Sinclair:
“It is difficult to get a man to understand something, when his salary depends upon his not understanding it.”
It also shows that the BBC still hasn’t learned the lessons in Steve Jones’ excellent “Review of impartiality and accuracy of the BBC’s coverage of science“. Every time I appear in such a programme, they feel obliged to invite a member of the flat earth society to propagate their make-believe.
Acupuncture for infantile colic – misdirection in the media or over-reaction from a sceptic blogger?
26 Jan, 17 | by Dr Mike Cummings
So there has been a big response to this paper press released by BMJ on behalf of the journal Acupuncture in Medicine. The response has been influenced by the usual characters – retired professors who are professional bloggers and vocal critics of anything in the realm of complementary medicine. They thrive on oiling up and flexing their EBM muscles for a baying mob of fellow sceptics (see my ‘stereotypical mental image’ here). Their target in this instant is a relatively small trial on acupuncture for infantile colic. Deserving of being press released by virtue of being the largest to date in the field, but by no means because it gave a definitive answer to the question of the efficacy of acupuncture in the condition. We need to wait for an SR where the data from the 4 trials to date can be combined.
So what about the research itself? I have already said that the trial was not definitive, but it was not a bad trial. It suffered from under-recruiting, which meant that it was underpowered in terms of the statistical analysis. But it was prospectively registered, had ethical approval and the protocol was published. Primary and secondary outcomes were clearly defined, and the only change from the published protocol was to combine the two acupuncture groups in an attempt to improve the statistical power because of under recruitment. The fact that this decision was made after the trial had begun means that the results would have to be considered speculative. For this reason the editors of Acupuncture in Medicine insisted on alteration of the language in which the conclusions were framed to reflect this level of uncertainty.
DC has focussed on multiple statistical testing and p values. These are important considerations, and we could have insisted on more clarity in the paper. P values are a guide and the 0.05 level commonly adopted must be interpreted appropriately in the circumstances. In this paper there are no definitive conclusions, so the p values recorded are there to guide future hypothesis generation and trial design. There were over 50 p values reported in this paper, so by chance alone you must expect some to be below 0.05. If one is to claim statistical significance of an outcome at the 0.05 level, ie a 1:20 likelihood of the event happening by chance alone, you can only perform the test once. If you perform the test twice you must reduce the p value to 0.025 if you want to claim statistical significance of one or other of the tests. So now we must come to the predefined outcomes. They were clearly stated, and the results of these are the only ones relevant to the conclusions of the paper. The primary outcome was the relative reduction in total crying time (TC) at 2 weeks. There were two significance tests at this point for relative TC. For a statistically significant result, the p values would need to be less than or equal to 0.025 – neither was this low, hence my comment on the Radio 4 Today programme that this was technically a negative trial (more correctly ‘not a positive trial’ – it failed to disprove the null hypothesis ie that the samples were drawn from the same population and the acupuncture intervention did not change the population treated). Finally to the secondary outcome – this was the number of infants in each group who continued to fulfil the criteria for colic at the end of each intervention week. There were four tests of significance so we need to divide 0.05 by 4 to maintain the 1:20 chance of a random event ie only draw conclusions regarding statistical significance if any of the tests resulted in a p value at or below 0.0125. Two of the 4 tests were below this figure, so we say that the result is unlikely to have been chance alone in this case. With hindsight it might have been good to include this explanation in the paper itself, but as editors we must constantly balance how much we push authors to adjust their papers, and in this case the editor focussed on reducing the conclusions to being speculative rather than definitive. A significant result in a secondary outcome leads to a speculative conclusion that acupuncture ‘may’ be an effective treatment option… but further research will be needed etc…
Now a final word on the 3000 plus acupuncture trials that DC loves to mention. His point is that there is no consistent evidence for acupuncture after over 3000 RCTs, so it clearly doesn’t work. He first quoted this figure in an editorial after discussing the largest, most statistically reliable meta-analysis to date – the Vickers et al IPDM. DC admits that there is a small effect of acupuncture over sham, but follows the standard EBM mantra that it is too small to be clinically meaningful without ever considering the possibility that sham (gentle acupuncture plus context of acupuncture) can have clinically relevant effects when compared with conventional treatments. Perhaps now the best example of this is a network meta-analysis (NMA) using individual patient data (IPD), which clearly demonstrates benefits of sham acupuncture over usual care (a variety of best standard or usual care) in terms of health-related quality of life (HRQoL).
30 January 2017
I got an email from the BMJ asking me to take part in a BMJ Head-to-Head debate about acupuncture. I did one of these before, in 2007, but it generated more heat than light (the only good thing to come out of it was the joke about leprechauns). So here is my polite refusal.
Thanks for the invitation, Perhaps you should read the piece that I wrote after the Today programme
Why don’t you do these Head to Heads about genuine controversies? To do them about homeopathy or acupuncture is to fall for the “manufactured doubt” stratagem that was used so effectively by the tobacco industry to promote smoking. It’s the favourite tool of snake oil salesman too, and th BMJ should see that and not fall for their tricks.
Such pieces night be good clickbait, but they are bad medicine and bad ethics.
All the best
‘We know little about the effect of diet on health. That’s why so much is written about it’. That is the title of a post in which I advocate the view put by John Ioannidis that remarkably little is known about the health effects if individual nutrients. That ignorance has given rise to a vast industry selling advice that has little evidence to support it.
The 2016 Conference of the so-called "College of Medicine" had the title "Food, the Forgotten Medicine". This post gives some background information about some of the speakers at this event. I’m sorry it appears to be too ad hominem, but the only way to judge the meeting is via the track record of the speakers.
Quite a lot has been written here about the "College of Medicine". It is the direct successor of the Prince of Wales’ late, unlamented, Foundation for Integrated Health. But unlike the latter, its name is disguises its promotion of quackery. Originally it was going to be called the “College of Integrated Health”, but that wasn’t sufficently deceptive so the name was dropped.
For the history of the organisation, see
The conference programme (download pdf) is a masterpiece of bait and switch. It is a mixture of very respectable people, and outright quacks. The former are invited to give legitimacy to the latter. The names may not be familiar to those who don’t follow the antics of the magic medicine community, so here is a bit of information about some of them.
The introduction to the meeting was by Michael Dixon and Catherine Zollman, both veterans of the Prince of Wales Foundation, and both devoted enthusiasts for magic medicne. Zollman even believes in the battiest of all forms of magic medicine, homeopathy (download pdf), for which she totally misrepresents the evidence. Zollman works now at the Penny Brohn centre in Bristol. She’s also linked to the "Portland Centre for integrative medicine" which is run by Elizabeth Thompson, another advocate of homeopathy. It came into being after NHS Bristol shut down the Bristol Homeopathic Hospital, on the very good grounds that it doesn’t work.
Now, like most magic medicine it is privatised. The Penny Brohn shop will sell you a wide range of expensive and useless "supplements". For example, Biocare Antioxidant capsules at £37 for 90. Biocare make several unjustified claims for their benefits. Among other unnecessary ingredients, they contain a very small amount of green tea. That’s a favourite of "health food addicts", and it was the subject of a recent paper that contains one of the daftest statistical solecisms I’ve ever encountered
"To protect against type II errors, no corrections were applied for multiple comparisons".
If you don’t understand that, try this paper.
The results are almost certainly false positives, despite the fact that it appeared in Lancet Neurology. It’s yet another example of broken peer review.
It’s been know for decades now that “antioxidant” is no more than a marketing term, There is no evidence of benefit and large doses can be harmful. This obviously doesn’t worry the College of Medicine.
Margaret Rayman was the next speaker. She’s a real nutritionist. Mixing the real with the crackpots is a standard bait and switch tactic.
Eleni Tsiompanou, came next. She runs yet another private "wellness" clinic, which makes all the usual exaggerated claims. She seems to have an obsession with Hippocrates (hint: medicine has moved on since then). Dr Eleni’s Joy Biscuits may or may not taste good, but their health-giving properties are make-believe.
Andrew Weil, from the University of Arizona
gave the keynote address. He’s described as "one of the world’s leading authorities on Nutrition and Health". That description alone is sufficient to show the fantasy land in which the College of Medicine exists. He’s a typical supplement salesman, presumably very rich. There is no excuse for not knowing about him. It was 1988 when Arnold Relman (who was editor of the New England Journal of Medicine) wrote A Trip to Stonesville: Some Notes on Andrew Weil, M.D..
“Like so many of the other gurus of alternative medicine, Weil is not bothered by logical contradictions in his argument, or encumbered by a need to search for objective evidence.”
This blog has mentioned his more recent activities, many times.
Alex Richardson, of Oxford Food and Behaviour Research (a charity, not part of the university) is an enthusiast for omega-3, a favourite of the supplement industry, She has published several papers that show little evidence of effectiveness. That looks entirely honest. On the other hand, their News section contains many links to the notorious supplement industry lobby site, Nutraingredients, one of the least reliable sources of information on the web (I get their newsletter, a constant source of hilarity and raised eyebrows). I find this worrying for someone who claims to be evidence-based. I’m told that her charity is funded largely by the supplement industry (though I can’t find any mention of that on the web site).
Stephen Devries was a new name to me. You can infer what he’s like from the fact that he has been endorsed byt Andrew Weil, and that his address is "Institute for Integrative Cardiology" ("Integrative" is the latest euphemism for quackery). Never trust any talk with a title that contains "The truth about". His was called "The scientific truth about fats and sugars," In a video, he claims that diet has been shown to reduce heart disease by 70%. which gives you a good idea of his ability to assess evidence. But the claim doubtless helps to sell his books.
Prof Tim Spector, of Kings College London, was next. As far as I know he’s a perfectly respectable scientist, albeit one with books to sell, But his talk is now online, and it was a bit like a born-again microbiome enthusiast. He seemed to be too impressed by the PREDIMED study, despite it’s statistical unsoundness, which was pointed out by Ioannidis. Little evidence was presented, though at least he was more sensible than the audience about the uselessness of multivitamin tablets.
Simon Mills talked on “Herbs and spices. Using Mother Nature’s pharmacy to maintain health and cure illness”. He’s a herbalist who has featured here many times. I can recommend especially his video about Hot and Cold herbs as a superb example of fantasy science.
Annie Anderson, is Professor of Public Health Nutrition and
Founder of the Scottish Cancer Prevention Network. She’s a respectable nutritionist and public health person, albeit with their customary disregard of problems of causality.
Patrick Holden is chair of the Sustainable Food Trust. He promotes "organic farming". Much though I dislike the cruelty of factory farms, the "organic" industry is largely a way of making food more expensive with no health benefits.
The Michael Pittilo 2016 Student Essay Prize was awarded after lunch. Pittilo has featured frequently on this blog as a result of his execrable promotion of quackery -see, in particular, A very bad report: gamma minus for the vice-chancellor.
Nutritional advice for patients with cancer. This discussion involved three people.
Professor Robert Thomas, Consultant Oncologist, Addenbrookes and Bedford Hospitals, Dr Clare Shaw, Consultant Dietitian, Royal Marsden Hospital and Dr Catherine Zollman, GP and Clinical Lead, Penny Brohn UK.
Robert Thomas came to my attention when I noticed that he, as a regular cancer consultant had spoken at a meeting of the quack charity, “YestoLife”. When I saw he was scheduled tp speak at another quack conference. After I’d written to him to point out the track records of some of the people at the meeting, he withdrew from one of them. See The exploitation of cancer patients is wicked. Carrot juice for lunch, then die destitute. The influence seems to have been temporary though. He continues to lend respectability to many dodgy meetings. He edits the Cancernet web site. This site lends credence to bizarre treatments like homeopathy and crystal healing. It used to sell hair mineral analysis, a well-known phony diagnostic method the main purpose of which is to sell you expensive “supplements”. They still sell the “Cancer Risk Nutritional Profile”. for £295.00, despite the fact that it provides no proven benefits.
Robert Thomas designed a food "supplement", Pomi-T: capsules that contain Pomegranate, Green tea, Broccoli and Curcumin. Oddly, he seems still to subscribe to the antioxidant myth. Even the supplement industry admits that that’s a lost cause, but that doesn’t stop its use in marketing. The one randomised trial of these pills for prostate cancer was inconclusive. Prostate Cancer UK says "We would not encourage any man with prostate cancer to start taking Pomi-T food supplements on the basis of this research". Nevertheless it’s promoted on Cancernet.co.uk and widely sold. The Pomi-T site boasts about the (inconclusive) trial, but says "Pomi-T® is not a medicinal product".
There was a cookery demonstration by Dale Pinnock "The medicinal chef" The programme does not tell us whether he made is signature dish "the Famous Flu Fighting Soup". Needless to say, there isn’t the slightest reason to believe that his soup has the slightest effect on flu.
In summary, the whole meeting was devoted to exaggerating vastly the effect of particular foods. It also acted as advertising for people with something to sell. Much of it was outright quackery, with a leavening of more respectable people, a standard part of the bait-and-switch methods used by all quacks in their attempts to make themselves sound respectable. I find it impossible to tell how much the participants actually believe what they say, and how much it’s a simple commercial drive.
The thing that really worries me is why someone like Phil Hammond supports this sort of thing by chairing their meetings (as he did for the "College of Medicine’s" direct predecessor, the Prince’s Foundation for Integrated Health. His defence of the NHS has made him something of a hero to me. He assured me that he’d asked people to stick to evidence. In that he clearly failed. I guess they must pay well.
This is my version of a post which I was asked to write for the Independent. It’s been published, though so many changes were made by the editor that I’m posting the original here (below).
Superstition is rife in all sports. Mostly it does no harm, and it might even have a placebo effect that’s sufficient to make a difference of 0.01%. That might just get you a medal. But what does matter is that superstition has given rise to an army of charlatans who are only to willing to sell their magic medicine to athletes, most of whom are not nearly as rich as Phelps.
So much has been said about cupping during the last week
that it’s hard to say much that’s original. Yesterday I did six radio interviews and two for TV, and today Associated Press TV came to film a piece about it. Everyone else must have been on holiday. The only one I’ve checked was the piece on the BBC News channel. That one didn’t seem to go too badly, so it’s here
BBC news coverage
It starts with the usual lengthy, but uninformative, pictures of someone being cupped, The cupper in this case was actually a chiropractor, Rizwhan Suleman. Chiropractic is, of course a totally different form of alternative medicine and its value has been totally discredited in the wake of the Simon Singh case. It’s not unusual for people to sell different therapies with conflicting beliefs. Truth is irrelevant. Once you’ve believed one impossible thing, it seems that the next ones become quite easy.
The presenter, Victoria Derbyshire, gave me a fair chance to debunk it afterwards.
Nevertheless, the programme suffered from the usual pretence that there is a controversy about the medical value of cupping. There isn’t. But despite Steve Jones’ excellent report to the BBC Trust, the media insist on giving equal time to flat-earth advocates. The report, (Review of impartiality and accuracy of the BBC’s coverage of science) was no doubt commissioned with good intentions, but it’s been largely ignored.
Still worse, the BBC News Channel, when it repeated the item (its cycle time is quite short) showed only Rizwhan Suleman and cut out my comments altogether. This is not false balance. It’s no balance whatsoever. A formal complaint has been sent. It is not the job of the BBC to provide free advertising to quacks.
After this, a friend drew my attention to a much worse programme on the subject.
The Jeremy Vine show on BBC Radio 2, at 12.00 on August 10th, 2016. This was presented by Vanessa Feltz. It was beyond appalling. There was absolutely zero attempt at balance, false or otherwise. The guest was described as being am "expert" on cupping. He was Yusef Noden, of the London Hijama Clinic, who "trained and qualified with the Hijama & Prophetic Medicine Institute". No doubt he’s a nice bloke, but he really could use a first year course in physiology. His words were pure make-believe. His repeated statements about "withdrawing toxins" are well know to be absolutely untrue. It was embarrassing to listen to. If you really want to hear it, here is an audio recording.
The Jeremy Vine show
This programme is one of the worst cases I’ve heard of the BBC mis-educating the public by providing free advertising for quite outrageous quackery. Another complaint will be submitted. The only form of opposition was a few callers who pointed out the nonsense, mixed with callers who endorsed it. That is not, by any stretch of the imagination, fair and balanced.
It’s interesting that, although cupping is often associated with Traditional Chinese Medicine, neither of the proponents in these two shows was Chinese, but rather they were Muslim. This should not be surprising as neither cupping nor acupuncture are exclusively Chinese. Similar myths have arisen in many places. My first encounter with this particular branch of magic medicine was when I was asked to make a podcast for “Things Unseen”, in which I debated with a Muslim hijama practitioner and an Indian Ayurvedic practitioner. It’s even harder to talk sense to practitioners of magic medicine who believe that god is on their side, as well as believing that selling nonsense is a good way to make a living.
An excellent history of the complex emergence of similar myths in different parts of the world has been published by Ben Kavoussi, under the title "Acupuncture is astrology with needles".
Now the original version of my blog for the Independent.
Cupping: Michael Phelps and Gwyneth Paltrow may be believers, but the truth behind it is what really sucks
The sight of Olympic swimmer, Michael Phelps, with bruises on his body caused by cupping resulted in something of a media feeding-frenzy this week. He’s a great athlete so cupping must be responsible for his performance, right? Just as cupping must be responsible for the complexion of an earlier enthusiast, Gwyneth Paltrow.
The main thing in common between Phelps and Paltrow is that they both have a great deal of money, and neither has much interest in how you distinguish truth from myth. They can afford to indulge any whim, however silly.
And cupping is pretty silly. It’s a pre-scientific medical practice that started in a time when there was no understanding of physiology, much like bloodletting. Indeed one version does involve a bit of bloodletting. Perhaps bloodletting is the best argument against the belief that it’s ancient wisdom, so it must work. It was a standard part of medical treatment for hundreds of years, and killed countless people.
It is desperately implausible that putting suction cups on your skin would benefit anything, so it’s not surprising that there is no worthwhile empirical evidence that it does. The Chinese version of cupping is related to acupuncture and, unlike cupping, acupuncture has been very thoroughly tested. Over 3000 trials have failed to show any benefit that’s big enough to benefit patients. Acupuncture is no more than a theatrical placebo. And even its placebo effects are too small to be useful.
At least it’s likely that cupping usually does no lasting damage.. We don’t know for sure because in the world of alternative medicine there is no system for recording bad effects (and there is a vested interest in not reporting them). In extreme cases, it can leave holes in your skin that pose a serious danger of infection, but most people probably end up with just broken capillaries and bruises. Why would anyone want that?
The answer to that question seems to be a mixture of wishful thinking about the benefits and vastly exaggerated claims made by the people who sell the product.
It’s typical that the sales people can’t even agree on what the benefits are alleged to be. If selling to athletes, the claim may be that it relieves pain, or that it aids recovery, or that it increases performance. Exactly the same cupping methods are sold to celebs with the claim that their beauty will be improved because cupping will “boost your immune system”. This claim is universal in the world of make-believe medicine, when the salespeople can think of nothing else. There is no surer sign of quackery. It means nothing whatsoever. No procedure is known to boost your immune system. And even if anything did, it would be more likely to cause inflammation and blood clots than to help you run faster or improve your complexion.
It’s certainly most unlikely that sucking up bits of skin into evacuated jars would have any noticeable effect on blood flow in underlying muscles, and so increase your performance. The salespeople would undoubtedly benefit from a first year physiology course.
Needless to say, they haven’t tried to actually measuring blood flow, or performance. To do that might reduce sales. As Kate Carter said recently “Eating jam out of those jars would probably have a more significant physical impact”.
The problem with all sports medicine is that tiny effects could make a difference. When three hour endurance events end with a second or so separating the winner from the rest, that is an effect of less than 0.01%. Such tiny effects will never be detectable experimentally. That leaves the door open to every charlatan to sell miracle treatments that might just work. If, like steroids, they do work, there is a good chance that they’ll harm your health in the long run.
You might be better off eating the jam.
Here is a very small selection of the many excellent accounts of cupping on the web.
There have been many good blogs. The mainstream media have, on the whole, been dire. Here are three that I like,
In July 2016, Orac posted in ScienceBlogs. "What’s the harm? Cupping edition". He used his expertise as a surgeon to explain the appalling wounds that can be produced by excessive cupping.
Photo from news,com.au
Timothy Caulfield, wrote "Olympic debunk!". He’s Chair in Health Law and Policy at the University of Alberta, and the author of Is Gwyneth Paltrow Wrong about Everything.
“The Olympics are a wonderful celebration of athletic performance. But they have also become an international festival of sports pseudoscience. It will take an Olympic–sized effort to fight this bunk and bring a win to the side of evidence-based practice.”
Jennifer Raff wrote Pseudoscience is common among elite athletes outside of the Olympics too…and it makes me furious. She works on the genomes of modern and ancient people at the University of Kansas, and, as though that were not a full-time job for most people, she writes blogs, books and she’s also "training (and occasionally competing) in Muay Thai, boxing, BJJ, and MMA".
"I’m completely unsurprised to find that pseudoscience is common among the elite athletes competing in the Olympics. I’ve seen similar things rampant in the combat sports world as well."
What she writes makes perfect sense. Just don’t bother with the comments section which is littered with Trump-like post-factual comments from anonymous conspiracy theorists.