Science in Society Archive

Mobile Phones Damage the Brain

Laboratory experiments show that electromagnetic fields from mobile phones destroy the blood brain barrier and damage neurons even 50 days after a single exposure in rats Dr. Mae-Wan Ho

Leif Salford at Lund University, Sweden, is head of an interdisciplinary team that has been studying the effects of EMFs on rat brain since 1988, with a major interest in the blood-brain barrier (BBB). In mammals including humans, the BBB protects the brain from potentially harmful compounds circulating in the blood, so normally, very little passes from the blood to the brain.

Their studies revealed that EMFs emitted by mobile phones at extremely low ‘non-thermal’ levels leads to increased permeability of the BBB both immediately after 2 hour of exposure, and also at 7, 14 and 50 days afterwards. Furthermore, damaging effects on neurons have been found even at 28 and 50 days after the single exposure [1]. The human BBB is very similar to that of rats.

We have described these studies in 2004 [2] (Mobile Phones & Brain Damage, SiS 24), and this is an updated, more in-depth report.  

Mobile phone EMFs up to 1018 times over natural background

The power density of the microwave background in space is about 0.4 mW/m2. On earth, the natural MW background is much lower, estimated to be in the order of 10-15 to 10-8 mW/m2. Artificial MWs were not produced until 1886, when German physicist Heinrich Hertz first broadcast and received radio waves. Since then, MWs have been the carriers of telegraphic data between stations on earth and between earth and the satellites. In the 1950s, the high frequency radio waves (RFs) were used in FM radio and television. Later, MWs were increasing used by many in mobile phones, and a far greater population became exposed to MWs through passive mobile phoning and MW-emitting base stations sited everywhere. As a result, the artificially produced general MW background in our environment is some 1011 to 1018 times the natural MW background from space.

Blood brain barrier prevents harmful compounds getting to the brain

The BBB was discovered by German bacteriologist Paul Ehrlich and his student Edwin Goldman. They found that when dyes were injected into the blood, the brain tissue was not stained, and only became stained when trypan blue was injected directly into the brain ventricles. A barrier between blood and brain at the site of the brain micro blood vessels appeared to be a logical explanation.

In fact, a BBB exists not only in mammals, but in all vertebrates and many invertebrates including insects, crustaceans, cephalopod molluscs such as the cuttlefish, and in land snails.

The BBB is formed by the endothelial cells lining the inside of the capillaries (fine blood vessels of the brain), which are sealed together with tight junctions composed of the proteins occluding, claudin, and zonula occludens (see Fig. 1). No gaps are left between the endothelial cells.

Outside the blood vessel, 25 percent of  the surface is covered with pericytes, a kind of blood cells capable of phagocytosis (engulfing bacteria and viruses), and contribute significantly to the immune response of the central nervous system, as well as to maintaining  the stability of the blood vessels. Surrounding the endothelial cells and the pericytes is a bilayer basal membrane that supports the outside surface of the endothelium and may also act as a barrier to macromolecules. The outer surface of the basal membrane is surrounded by brain cells called protoplasmic astrocytes, which are thought to be involved in regulation and repair of the BBB. Their protrusions, called end feet, cover the basal membrane and form a second barrier to hydrophilic molecules, but also connect the endothelium to the neurons. The BBB is not just a physical barrier, but also an enzymatic barrier with the special capability of metabolizing solutes such as drugs and nutrients.

Figure 1 Anatomy of the blood brain barrier

In humans, the protoplasmic astrocytes are 27 times the volume of those in rats, and far more elaborate. They reside near blood vessels, and their end feet completely encompass the vessels while those of rat form rosettes around the vessels.

The BBB allows water, most lipid-soluble molecules, oxygen and carbon dioxide to diffuse from blood to nerve cells; it is also slightly permeable to ions such as Na+, K+, Cl-. However, proteins and most-water-soluble compounds are excluded. During certain pathological conditions such as tumour formation, infarct, infections, traumas, epileptic seizures or severe hypertension, the selective permeability of the BBB is compromised. The result can be cerebral oedema (water in the brain), increased intracranial pressure and irreversible brain damage. Also, toxic substances from the blood can now enter the neurons in the brain.

EMF exposure and BBB

Experiments carried out as early as the 1970s have demonstrated an increased leakage of fluorescein dye into the brain after 30 minutes of pulsed and continuous waves exposure at 1 200 MHz. However, these findings could not be replicated in all laboratories and a debate broke out on whether the effect was due to microwave heating of the tissues.

Salford’s group began work on the rat brain in 1988, and found increased permeability of the BBB for albumin, which is a natural constituent of the blood, without the need to inject any foreign substance.

They started their experiments with the frequency modulation 16 Hz and its harmonics, 4, 8, 16, and also 50 Hz, which was believed to be relevant, as it is the standard line frequency of the European power system, with a carrier wave of 915 MHz. Initially, 217 Hz modulation was added, as that was the frequency of the then planned GSM (Global System for Mobile Communication). The early work, published in the 1990s concluded that there was a significant difference between the albumin leaked from the brain capillaries into the brain tissue between the exposed and control groups.

Amplitude window for effect on BBB

On re-analysis of the data, they found that for the experiment with 217 Hz modulation, and at SAR values of 0.2 to 4 mW/kg, the 48 exposed rats had increased albumin leakage significant at p<0.001 compared with the 48 controls. But at SAR (specific absorption rate) values of 25-50 mW/kg, there was no significant difference between the 22 exposed rats compared with the matched controls. Thus, there was a remarkable amplitude window, such that a more pronounced effect was demonstrated at non-thermal levels below10 mw/kg. The SAR value of around 1 mW/kg exists at a distance of more than 1 m away from the mobile phone antenna, and at a distance of about 150-200 m from a base station.

Long lasting effect of a single exposure

In the early experiments, the effects on BBB were investigated immediately after whole animal exposure. Later, Salford’s team performed a series of experiments where the animals were allowed to survive for 7 day, 14 days, 28 days or 50 days after a single 2-hour exposure to the radiation from a GSM mobile phone (915 MHz, 217 Hz modulation). The peak power output from the GSM mobile phone fed into the exposure chambers containing the animals were 1, 10, 100 and 1 000 mW, resulting in average whole-body SAR of 0.12, 1.2, 12 and 120 mW/kg for the four different exposure groups.

Albumin leakage was detected in rats that had survived for 7 and 14 days after exposure, but not for those surviving for 28 days. After 50 days, however, albumin leakage was significantly increased again.

The albumin leaked into the brain also spread to the surrounding brain tissue, and a significantly increased uptake of albumin in the cytoplasm of neurons could be seen in the GSM exposed animals surviving 7 and 14 days after exposure, but not in those surviving 28 or 50 days (see Fig. 2).

Figure 2 Albumin leakage and neurone damage after EMF exposure

It has been suggested that albumin is the most likely neurotoxin in serum. Injection of albumin into the brain of rats gave rise to neuronal damage and neuronal death. It also caused leakage of the rat’s own albumin in and around the area of neuronal damage. Salford thinks that the initial albumin leakage into the brain tissue, though not sufficient to damage neurons, may have started a vicious cycle of further leakages that led to damaged neurons at the later times. Damaged neurons or dark neurons have irregular cell outlines, increased chromatin density in the nucleus and cytoplasm and intensely and homogenously stained nucleus.

In a recent long-term study, rats were exposed to GSM radiation 2 hours weekly during a period of 55 weeks at 0.5mW/kg and 60 mW/kg. After the protracted exposure, the rats’ behaviour and memory were tested. The behaviour of the animals was not affected, but the GSM exposed rats had significantly impaired episodic memory compared to controls. However, no significant histological differences could be found between exposed and control groups for albumin leakage or neuronal damage. The researchers suggested that during the long period of exposure, some adaptation process might have occurred to prevent albumin leakage and neuronal damage, but that did not compensate for the cognitive impairment.

The distinctive approach of the Salford group is the use of extremely low intensity and non-thermal levels of exposure, whereas most other laboratories that failed to find significant effects have used exposure levels 10 or 100 times higher (though still non-thermal). This is reminiscent of the amplitude window seen in a whole range of ion cyclotron resonance effects of combined static and alternating magnetic fields that occur only at extremely weak fields (see [2] Quantum Coherent Water, Non-thermal EMF effects, & Homeopathy, SiS 51) that can only be explained in terms of quantum electrodynamical coherence of water.

Relevance to human mobile phone use

The SAR value of around 1 mW/kg exists at a distance of more than 1 m away from the mobile phone antenna, and about 150-200 m from a base station. When the mobile phone is held next to the ear, the SAR value of about 1 mW/kg exists in the most central part of the brain, and when a hands-free set is used, and the phone is for example in the pocket, there will still be microwaves reaching the brain, though the value of around 1 mWkg will be in more superficial parts of the brain.

In many safety standard documents, a SAR limit of 4W/kg is set for localized SAR of limbs, and 2W/kg for localized SAR of head and trunk. The reasons for choosing this value is a series of studies performed in the 1970s and 1980s, which tested the trained behaviour of rats, squirrel monkeys and rhesis monkeys after MW exposure. It was found that body temperature increases of 1 C or more above the baseline body temperature resulted in changes of behaviour. Notably, a SAR of nearly 4 W/kg was needed to produce this 1 C change of body temperature. These safety limits are clearly inadequate for all the described non-thermal effects.

Salford is in no doubt that [1] “non-thermal electromagnetic fields from mobile phones and base stations do have effects upon the human brain.”

Article first published 06/07/11


  1. Salford LG, Nittby H, Brun A, Eberhardt J Malmgren L and Persson BRR. Effects of microwave radiation upon the mammalian blood-brain barrier. In Giuliani L and Soffritti M. eds. Non-thermal Effects and Mechanisms of Interaction between electromagnetic Fields and Living Matter, an ICEMS Monograph, Ramazzini Institute, European Journal of Oncology Library vol.5, pp. 333-55, Bologna, Italy, 2010.
  2. Ho MW. Mobile phones & brain damage. Science in Society 24, 50-51, 2004.
  3. Ho MW. Non-thermal EMF effects, quantum coherent water & homeopathy. Science in Society 51 (to appear).

Got something to say about this page? Comment

Comment on this article

Comments may be published. All comments are moderated. Name and email details are required.

Email address:
Your comments:
Anti spam question:
How many legs on a tripod?

There are 5 comments on this article so far. Add your comment above.

Pam Peterson Comment left 9th July 2011 19:07:30
I want to thank you very much for a great web site and great informantion you give to the people who care to know what is being aloud in this country. My question is does the same go for using the speeker phone instead of using the hand held to your head? Thank you, Pam

claude saint-jarre Comment left 9th July 2011 19:07:50
Perhaps you should give informations on how to protect one self from this pollution: what parents should say to teenagers. Thank you ery much, claude saint-jarre

maewan Comment left 9th July 2011 19:07:04
Pam Peterson, thanks for your praise. Speaker phones as such are not the problem. But if they are attached to cordless phones, the same hazards apply because the base station of cordless phones sends out wireless signals constantly, see recent article: Wireless phones & Brain Cancer. Claude SJ, you should read other articles in the series such as the one here for advice on how to make mobile phone usage more safe:

Sagar Comment left 14th July 2011 01:01:46
This is good research, and we are lucky to have you good people at isis doing this for the planet. The next wave of wireless is of course broadband. I dont have it at home, but cant avoid it outside, as I am surrounded by laptops, ipad, etc, etc. Is there any technology being developed to make wireless safer ofr not emit so much radiation? What is Scalar technology. I have been told that scalar can reduce emf? With this research now coming out, is it feasible to now produce a video on emf effects on birds, bees and humans?

Leon Comment left 5th May 2012 23:11:50
By the way, what about that so-called "research" many people quote like the WHO EMF Project? This testimony about Michael Repacholi is particularly interesting: