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Pulsed Electromagnetic Field Woo

Donate The latest form of magnet therapy promises to cure everything from headaches to cancer.  

by Brian Dunning

Filed under Alternative Medicine, Consumer Ripoffs

Skeptoid Podcast #863
December 20, 2022
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Pulsed Electromagnetic Field Woo

Today we're going back to our alternative medicine files, and have a look at one of the more expensive and exotic-sounding treatments on the market: Pulsed Electromagnetic Field (PEMF) devices, promising to end your pain and cure virtually any disease using nothing more than a magnet. If this sounds too good to be true, then you might not be too surprised to learn what the medical consensus is on this. Nevertheless the market is flooded with countless such devices, prompting one to wonder: Is it possible that health and pain-free living are really that easy? Let's find out.

An electromagnet is just a coil of wire, and when you pass electricity through the wire, the coil becomes a magnet. Think of the big ones at junkyards that lift old cars: power on, it's a magnet; power off, it's just a chunk of metal. By adjusting the power you can make it stronger or weaker, you can turn it on and off to pulse it, you can do just about anything you want by modulating the amount of electricity you send to it. That's how PEMF devices work. They're sold as mats that you can lay on, caps that cover your head, handheld versions, recliners, versions that strap to your back, even beds for your pets and full-body covers for your horse. Any way you can imagine to put an electromagnet near your body, someone sells a PEMF device that does that.

And they're not cheap — no, not cheap at all. Although you can sometimes find small handheld versions costing in the hundreds of dollars, most are in the thousands — some well into multiple thousands of dollars.

Also, before we go too far into this topic, let's take a really quick review of the electromagnetic field. The electromagnetic field is a property of space that applies to the entire universe. It is a vector field, meaning it is represented at every single point in space by a directional vector and a magnitude. Imagine a simple bar magnet. It doesn't create a magnetic field or have its own; it influences the magnetic field around it. You've seen diagrams of the magnetic field around a bar magnet; it's surrounded by arc-shaped lines that converge at its two poles, and the further away you get from it the less pronounced it is. Those lines don't really exist; they are made of little tiny arrows describing the strength and direction of the magnetic field at every point in space around the magnet. As a radio signal flies through, all those little arrows vibrate the tiniest bit, and that's electromagnetic radiation. Obi-Wan Kenobi described the electromagnetic field best: "It surrounds us and penetrates us; it binds the galaxy together."

So when you buy a PEMF device, the electromagnetic coils in it turn on and curve those flux lines in the magnetic field. Just as do so many devices in your house: Not just your refrigerator magnets, but every electrical appliance and every wireless device.

So considering the high cost, we should probably hope that these devices are medically beneficial. Here's a list of claimed benefits from one website that sells all kinds of PEMF mats and pads and other devices:

Pain relief.
Faster and better healing.
Reduced inflammation.
Improved circulation.
Better sleeping patterns.
Faster recovery from trauma, illness or injury because of enhanced cellular repair.
Elevated moods.
Increased physical energy.
Improved memory.
Anti-aging effects.

But note: they add that those are only "some" of the benefits! It goes on to say that it can also treat "old or recent injuries, certain types of cancer, and diseases such as arthritis." There are claims for migraines, for fibromyalgia, for chronic fatigue, for COVID-19. In fact, if you want to amuse yourself, google the name of any medical condition you can think of, plus the term PEMF. Seriously, do it. If there's one little maxim that we can draw from the entire history of examining medical devices or drugs that are said to cure just about everything you can be afflicted with, it is:

If it claims to treat everything,
it probably treats nothing.

If a medical product is a scam, there is one person you can bet your bottom dollar will be out there selling it, making false claims, aggressively lying about whatever he can to separate you from your money: Dr. Oz. Have a listen to his extraordinary word salad as he explains how PEMF supposedly works on his TV show:

Now the magnetic field turns on, and when it does, it activates these ions, these charged particles, and they're proteins and they're in their signals, and they stir these things up. And these charged particles bring in nutrients, but they also begin to influence things like blood supply. Now, when the blood vessels are going in here, the red blood cells are actually stacked, see they're stacked like that, they're not supposed to be stacked. When they're irritated, that happens. So when you pass magnetic fields through there, that yellow line, it opens up the blood vessel. It breaks apart these red cells so they're not stacked like coins. So you can get deep healing, better oxygen supply. So the healing process takes place. You don't just feel better, you are better. And that's an important advance for us, one that we haven't really been practicing until today, because today we're going to change that.

Well that's a bold claim. Oz also had a compelling argument for the skeptics:

And if you don't think this is real. Who here has had an MRI scan? A lot of folks. MRI scans work on these basic principles that magnets do. They are magnets. And so we had magnets in use in hospitals every single day.

Perhaps Oz is not aware that an MRI machine is used for non-invasive imaging, it's not used to treat pain. And it's great for imaging, because magnetic fields don't interact with the human body. It's not going to do anything to you, which is the basic reason all PEMF devices can be considered worthless snake oil.

Dr. Oz went on to explain how scientists find out what works and what doesn't, in his opinion:

You need to tell your doctor, do you know why? Because every other patient that that doctor sees is going to benefit because you were willing to put your hand up and say, you know what, I was having bad pain. I wasn't getting relief. The medications, the injections, the operations, they weren't working for me. I want to try this new therapy out. And you know what? It worked for me. Please share it with other people. That's how we learn medicine.

No, that's actually a very, very horrible way to learn medicine. It's a great way to learn what biases, preconceived notions, and expectations one individual patient might interpret on that particular day. Pardon me, who is not a doctor, for correcting an actual doctor on this; but Dr. Oz is speaking as a television pitchman and not as a medical researcher. We learn which treatments work and which ones don't not from personal anecdotes, but from randomized controlled trials.

So then let's be fair and see what the clinical trials of PEMF have found. I found one published study from 2007 that was properly randomized and placebo controlled, and sought to find out if these devices could treat chronic pain. They fitted PEMF devices to the heads of chronic pain patients for twice-daily sessions over a weeklong period. The result? "A differential effect of PEMF over sham treatment was noticed in patients with fibromyalgia, which approached statistical significance." In case you need help deciphering "approached statistical significance," it means "was not statistically significant."

The majority of articles promoting PEMF all refer back to a single old trial from way back in 1990, that found pulsed electromagnetic fields "significantly influence healing in tibial fractures with delayed union," meaning it can help broken bones heal faster when they weren't doing so on their own. This one study appears to be the cornerstone upon which most marketing of PEMF devices is based. However a 2011 analysis published in the Cochrane Database of Systematic Reviews sought to shed more light on all such research. They found a total of four such studies that included 125 participants, and found the use of PEMF in non-union bone fractures was "inconclusive and insufficient to inform current practice." Meaning, in short, there's no reason to use it.

Nevertheless a few PEMF devices are FDA approved for helping with non-union fractures. The vast majority of devices, however, are not. One of these websites has what I consider a completely honest explanation for why the gadgets they sell are not FDA approved:

FDA approval is not necessary for a treatment to work. Most PEMF manufacturers do not pursue this. It can be sought, but often comes with strict limitations on how devices can be marketed. The research needed to achieve approval can also be prohibitively expensive.

That's perfectly true. If you get FDA approved, you can no longer just say whatever you want to make up about your product, because now you're accountable to regulators. You can only make narrow statements about the specific condition they approved it for. And why do that when you're just trying to bilk customers out of money? I could sell a baseball bat as a massage device — and it would be perfectly legal for me to do so, as long as I wasn't making claims that it treats some disease. But if I sought FDA approval for that, I'd have to do all these studies and submit results and prove that it doesn't cause any harm, which it might.

And they're right about FDA approval not proving that a product works. All it means is the product is safe and can be manufactured to federal quality standards. Plenty of snake oil products meet that standard and are FDA approved, and yet don't have any therapeutic value at all.

Particularly entertaining are the "science explanations" given by sellers claiming to describe how and why these work — and, of course, no two websites give the same explanations, because the fact is that there is no mechanism by which these devices might interact with the human body. On the Science-Based Medicine blog in 2016, Dr. Steven Novella discussed the supposedly "science" claims made by a company that manufactured a PEMF pad, something that you'd lay on and it would be magnetic. One of these claims was "The EMPpad's PEMF technology has been developed to deliver an electromagnetic pulse at an intensity and frequency which mimics the Earth's magnetic field." Novella wrote:

One immediate question I had — if the device exactly mimics the Earth's magnetic field... then why is the device necessary? Aren't we all being exposed to the Earth's magnetic field all the time?

Of course we are. But moreover, at human scale, the Earth's magnetic field is relatively weak. It's just enough to keep a compass needle pointing toward magnetic North. But have you ever held even the smallest magnet near a compass? Even a tiny magnet's influence on the magnetic field is far stronger than the Earth's. What they are claiming is that if you were to take a compass and lay it on their PEMF mat, then turn it on, nothing would happen at all. Basic science tells us that, assuming the product actually does contain electromagnetic coils, turning it on would snap the compass needle around. If you feel you need to heal in an electromagnetic environment that mimics the Earth's, then all you need to do is be on Earth; the last thing you should want to do is buy a device that would spoil that.

And so, save your money. Please do not buy any PEMF device hoping to get miraculous treatment of some painful condition. As we so often observe here on Skeptoid, miraculously easy solutions to difficult problems are easy to sell, because we're all hopeful; but unfortunately, miracles usually don't have much science supporting them.

By Brian Dunning

Please contact us with any corrections or feedback.


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Cite this article:
Dunning, B. "Pulsed Electromagnetic Field Woo." Skeptoid Podcast. Skeptoid Media, 20 Dec 2022. Web. 20 Jul 2024. <>


References & Further Reading

Barrett, S. "Magnet Therapy: A Skeptical View." Quackwatch. Center for Inquiry, 29 Jun. 2008. Web. 8 Dec. 2022. <>

Griffin, X., Costa, M., Parsons, N., Smith, N. "Electromagnetic field stimulation for treating delayed union or non-union of long bone fractures in adults." Cochrane Database of Systematic Reviews. 13 Apr. 2011, Number 4: CD008471.

Light, D., Lexchin, J., Darrow, J. "Institutional Corruption of Pharmaceuticals and the Myth of Safe and Effective Drugs." Journal of Law, Medicine and Ethics. 1 Jun. 2013, Volume 14, Number 3: 590-610.

Novella, S. "Pulsed Electromagnetic Field Snake Oil." Science-Based Medicine. New England Skeptical Society, 8 Jun. 2016. Web. 6 Dec. 2022. <>

Sharrad, W. "A double-blind trial of pulsed electromagnetic fields for delayed union of tibial fractures." The Journal of Bone and Joint Surgery. 1 May 1990, Volume 72, Number 3: 347-355.

Thomas, A., et. al. "A randomized, double-blind, placebo-controlled clinical trial using a low-frequency magnetic field in the treatment of musculoskeletal chronic pain." Pain Research & Management. 1 Jan. 2007, Volume 12, Number 4: 249-258.


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