Ian Luxmoore investigates the claims for BioMag underlays.

I hear and see advertising for the BioMag Underlay on a regular basis in New Zealand media. They advertise extensively on TV and radio and have become a very well-known brand in this country. They produce a wool bed underlay that includes magnets which are promoted as providing pain relief. There are several other brands of magnetic underlay in the market in New Zealand and the conclusions here most likely apply to those as well, but for simplicity I focused my efforts on the most popular one.

The first step is to see what the BioMag actually claims and in the age of the internet the best resource for this is usually the company’s website (www.biomag.co.nz). In this case Bio-Mag have a pretty good site which is easy to follow and has a lot of information on it.

While their claims are restated in several different ways in different parts of the website, this premise really stood out:

“For years, the mainstream medical establishment’s response to pain has been to throw a pill at it.”

While there is some evidence that drug prescription rates are higher than necessary, any doctor trivially throwing pills at a problem would soon lose his or her practising license. The fact is that mainstream pain relief does work. It works effectively, time and time again, in clinical trials beyond count and in day-to-day life.

The website’s claim looks like an attempt to trivialise mainstream medicine so that people will be more inclined to consider the BioMag. This is not an uncommon tactic amongst alternative medicines and it also builds on the cynical view of drug companies held by many. They promote the BioMag as drug-free pain relief for a variety of ailments from arthritis to sciatica and numerous other causes to take advantage of this.

It is important to note here that nowhere do they say that the BioMag cures anything but it does claim to reduce the pain from various ailments. Some magnetic healing devices claim to cure cancer or other serious ailments and I think it is clear these are fraudulent, but the Bio-Mag does not claim this as far as I can tell.

How Does It Work?

So how is BioMag supposed to do what it claims? There are a myriad claims on the website. The main one however is that circulation is improved, and the connection between magnets and iron in the blood is invoked to explain this. They go on to explain:

“It does this by drawing trace elements, for instance, iron, towards the magnets. The human body contains about 5 grams of iron, much of it in the form of haemoglobin which plays a vital role moving oxygen from your lungs around your body.”

Firstly if the magnets do attract the iron in your blood won’t that just draw the blood towards the bed and hold it there? Logically one would expect it to do the exact opposite of increasing circulation. However that proves to be irrelevant because the iron in the body is locked up in haemoglobin molecules and is so diffuse that it is incapable of forming any kind of magnetic attraction. In fact it turns out that haemoglobin is actually slightly repelled by magnetic fields.

Perhaps the best response to the claim that magnets affect blood however was made on a blog entitled Crap-Based Medicine:

“The last time you got an MRI, did the enormous magnets tear all the blood out of your stupid body?”

MRIs are magnetic resonance imaging devices at hospitals that use very powerful magnets (0.5-3.0 Tesla) to create 3D images of the body. To put the power of these magnets in context, the biomag magnets are probably around the 0.01-0.05 Tesla mark so if anything was going to move blood an MRI would!

The second claim the BioMag makes is that the magnets stimulate nerve endings:

“The general consensus is that the magnetic force stimulates nerve-endings to improve blood flow to injured or swollen joints, causing the blood vessels to dilate.”

There are numerous papers exploring the impact of magnetic fields on nerve actions, and the results are quite variable. One common thread though seems to be that the mechanisms are largely unknown. One paper I found that did find an effect made the point that the strength and nature of the magnet need to be quite specific to have an impact on isolated mouse nerve impulses.

Even if the nerve endings are stimulated by magnets and this does lead to increased blood flow, if there is pain there then the nerves are already stimulated and the blood flow is already increased! The magnet has no work left to do. Moreover it seems very unlikely that a general magnetic field from the underlay would stimulate nerves only in places where there are injured or swollen joints – in fact one might expect the magnets to dilute this effect given that, if it does stimulate nerve endings, it would stimulate them everywhere. All told this line of reasoning simply doesn’t add up.

The BioMag site also claims that increased circulation increases the delivery of trace elements and nutrients around the body and aids in the removal of toxins. Both of these are irrelevant to the main claim of pain relief and are also highly suspect.

Other claims include influences on melatonin production (to aid sleep) although a 2003 paper by Touitou et al discovered large magnetic fields had no effect whatsoever on melatonin levels.

Finally they claim that the BioMag can correct excess acidity or alkalinity to bring the body “into a position of natural balance”. There is no obvious connection between magnets and pH levels, and it is worth noting that various parts of the body have varying pH levels for different purposes so one would hope these levels aren’t all affected.


I can find absolutely nothing on the website or elsewhere that indicates the product itself has been tested for efficacy in pain relief and sleep improvement. The BioMag site offers some journal papers and anecdotal evidence. I will deal with the anecdotal information in the next section.

The main reference on the site is to a 1997 paper entitled Response of pain to static magnetic fields in postpolio patients: A double-blinded pilot study, by Vallbona et al. There are a few points to note about this paper. Firstly it is a pilot study which is a rather tenuous basis for an entire product line. Secondly they only applied the magnets for 45 minutes which is quite different to sleeping on them overnight. Thirdly there was no follow-up so while this paper is potentially interesting, it doesn’t really tell us very much at all.

Good science is built up on as many studies as possible in order to give us the best possible picture, especially in highly subjective areas like pain. Twelve other papers are listed on the site but to save time I went hunting for any meta-analyses of static magnet therapy. A meta-analysis is where the author compiles the results from as many studies as he or she can find and determines if there is an overall benefit to be found given the breadth of studies conducted.

I found a 2007 meta-analysis that looked pretty thorough entitled Static magnets for reducing pain: systematic review and meta-analysis of randomized trials, by Pittler et al. This paper pulled together 29 studies, including the Vallbona study and most of the other references listed on the site. Their conclusion is telling:

“Overall, the meta-analysis suggested no significant effects of static magnets for pain relief relative to placebo.”

They did note that for one ailment (peripheral joint osteoarthritis) the “evidence is insufficient to exclude a clinically important benefit” but for all other ailments their conclusion was that there was no significant effect over placebo.

At the very best one can say that the literature is uncertain about the impact of magnets. What we can say is that there appears to be no peer-reviewed research about the BioMag products specifically and therefore its clinical efficacy rests on the somewhat inconclusive (and mostly negative) evidence for magnets in general.

The anecdotal evidence

While clinical evidence for the BioMag’s efficacy is sparse at best the anecdotal evidence is all over their website and advertising campaigns. Anecdotal evidence is much harder to take seriously than clinical evidence because it is uncontrolled and wide open to placebo, misinterpretation and even manipulation.

The BioMag site particularly emphasises the celebrities that endorse the product. While not an uncommon tactic amongst both legitimate and illegitimate products, ask yourself this: is a rugby star any more qualified than anyone else to comment on the efficacy of a bed product? Celebrities they may be. Sleep experts or medical doctors they are not. Their opinion is no more or less valid than any other lay opinion. Looking through the testimonials page we find videos of several prominent celebrities doing promos on Murray Deaker’s radio show plus numerous written endorsements on the site. I read through all the testimonials I could find and noted that, while every single testimonial mentions improved sleep, less than half specifically mention pain relief. In fact most of the video testimonials didn’t even mention pain, but they did spend a fair bit of time on how nice the wool is! Notably almost none of the testimonials made any specific mention of the magnets.

Explaining the anecdotal evidence

On the surface the anecdotal evidence seems convincing but it doesn’t take too much thought to find a logical explanation for most of it.

Firstly the BioMag is a luxury woollen underlay for a bed and relatively few people that already had a high-quality woollen underlay on their bed would actually purchase a BioMag. This means that the majority of people purchasing one are actually significantly improving their bed’s comfort and luxury. This in itself would be enough to account for a better night’s sleep, the most common reported benefit.

Secondly a lot of people suffer problematic pain in bed. Once you are comfortable and asleep you don’t feel pain so anything that makes your bed more comfortable and makes it easier for you to sleep will effectively alleviate pain. Also it is fairly well known that good sleep gives your body a chance to recuperate and that well-rested people are more likely to be motivated and lively. This builds a powerful explanatory scenario for the observed pain relief due to the BioMag.

Thirdly, a lot of people that buy this product expect to receive pain relief and better sleep. Given the cost, celebrity endorsements, and supposed science behind it, there cannot be a better environment for the placebo effect to manifest itself. Given how subjective pain is, if you curl up in a warm comfortable bed that never used to be that soft and comfortable it is no surprise that you’d think it was working and that would potentially increase the effect that the good sleep already has.


I think it is safe to say improving sleeping conditions is beneficial to people with all sorts of problems so it is most likely a benefit to installing a luxury wool underlay on a bed without one. However given everything I have read, the nature of the benefits of using the BioMag, and the general conclusions of the magnetic healing literature, I am strongly inclined to believe that the magnets do not contribute to any of the benefits of using the BioMag underlay.

Recommended Posts