6,486 Studies Reviewed. 85.2% of Original Studies Found Biological Effects. The Evidence is Clear.
All Exposure Types

SAR (Specific Absorption Rate)

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Specific Absorption Rate (SAR) measures the rate at which RF energy is absorbed by body tissue, expressed in watts per kilogram (W/kg). SAR is used to rate cell phones and other devices held against the body. The FCC limit for cell phones is 1.6 W/kg averaged over 1 gram of tissue.

Concern Level Thresholds

Based on Building Biology Institute guidelines (W/kg (watts per kilogram)):

No Concern
< 0.4 W/kg
Slight Concern
0.4 – 1.0 W/kg
Severe Concern
1.0 – 1.6 W/kg
Extreme Concern
> 1.6 W/kg (FCC limit)

See where common exposures fall on the scale:

A logarithmic scale showing your reading relative to Building Biology concern thresholds and FCC regulatory limits.Your SAR Exposure in ContextNo ConcernSlightSevereExtreme0.0010.010.1FCC Limit →0.00110 W/kg

Showing 898 studies with measured sar (specific absorption rate) exposure

Effects of GSM 1800 MHz on dendritic development of cultured hippocampal neurons.

Ning W, Xu SJ, Chiang H, Xu ZP, Zhou SY, Yang W, Luo JH · 2007

Researchers cultured hippocampal neurons from rats and exposed them to GSM 1800 MHz microwaves at either 2.4 or 0.8 W/kg for 15 minutes each day from DIV6 to DIV14. At 2.4 W/kg, the density and mobility of dendritic filopodia at DIV8 and the density of mature spines at DIV14 were significantly decreased, and the average length of dendrites per neuron at DIV10 and DIV14 was also decreased. Dendritic arborization was unaltered in the exposed neurons, and no significant changes were found in neurons exposed to 0.8 W/kg.

Oxidative StressNo Effects Found

Evaluation of Parameters of Oxidative Stress after In Vitro Exposure to FMCW- and CDMA-Modulated Radiofrequency Radiation Fields.

Hook et al. · 2004

Researchers exposed J774.16 mouse macrophage cells to FMCW radiation at 835.62 MHz and CDMA radiation at 847.74 MHz for 20–22 hours at a specific absorption rate of 0.8 W/kg. Cells were stimulated with γ-interferon and bacterial lipopolysaccharide before exposure. The results indicated that FMCW- and CDMA-modulated RF radiation did not alter parameters indicative of oxidative stress in J774.16 cells.

Oxidative StressNo Effects Found

Evaluation of parameters of oxidative stress after in vitro exposure to FMCW- and CDMA-modulated radiofrequency radiation fields.

Hook et al. · 2004

Researchers exposed mouse immune cells to cell phone radiation at 835-847 MHz for over 20 hours to test whether radiofrequency signals cause oxidative stress (cellular damage from harmful molecules). They found no evidence that either FMCW or CDMA modulated signals at 0.8 W/kg caused oxidative stress, cellular damage, or changes in the cells' natural antioxidant defenses. The study suggests that cell phone-type radiation at these levels does not trigger the cellular stress responses that can lead to health problems.

Effects of GSM signals during exposure to event related potentials (ERPs)

Bak M, Dudarewicz A, Zmyślony M, Sliwinska-Kowalska M · 2010

Researchers assessed the effect of electromagnetic field from the GSM mobile phone system on human brain function in volunteers. The assessment was based on event related potentials, with P300 latency, amplitude, and latency of the N1, N2, P2 waves analysed. The statistical analysis revealed an effect of EMF on P300 amplitude, with lower amplitudes observed only during exposure. No statistically significant changes were noted in the latencies of the N1, N2, P2 waves or in the latency of the P300 itself.

Effect of bluetooth headset and mobile phone electromagnetic fields on the human auditory nerve

Mandalà M et al. · 2013

Researchers conducted a study to verify whether Bluetooth devices reduce the auditory nerve effects seen with direct mobile phone electromagnetic field exposure, using the same experimental protocol as a prior investigation. Twelve patients underwent retrosigmoid vestibular neurectomy to treat definite unilateral Ménière's disease while being monitored with acoustically evoked CNAPs during direct mobile phone or Bluetooth headset exposure. Bluetooth electromagnetic fields did not produce any significant change in cochlear nerve activity, while mobile phone electromagnetic fields caused a significant decrease in CNAP amplitude and an increase in latency in all subjects.

Brain & Nervous SystemNo Effects Found

No effects of mobile phone use on cortical auditory change-detection in children: An ERP study.

Kwon MS et al. · 2010

Researchers tested whether cell phone radiation affects children's brain processing of sounds by placing GSM phones emitting 902 MHz signals next to 17 children's heads for 12 minutes while measuring brain activity. They found no statistically significant changes in the children's auditory processing abilities during exposure. However, the study was only large enough to detect major effects, meaning smaller impacts could have been missed.

Brain & Nervous SystemNo Effects Found

No effects of mobile phone use on cortical auditory change-detection in children: an ERP study

Kwon MS et al. · 2010

Auditory event-related potentials including P1, N2, mismatch negativity, and P3a were recorded from 17 children aged 11–12 years using the multi-feature paradigm. During recording, an ordinary GSM mobile phone emitting 902 MHz pulsed at 217 Hz was placed on the ear over the left or right temporal area with SAR1g = 1.14 W/kg and SAR10g = 0.82 W/kg. The short exposure of two 6 min blocks per side had no statistically significant effects on the neural change-detection profile measured with MMN. The study only had sufficient statistical power to detect a large effect size.

Brain & Nervous SystemNo Effects Found

Preattentive auditory information processing under exposure to the 902 MHz GSM mobile phone electromagnetic field: A mismatch negativity (MMN) study.

Kwon MS et al. · 2009

Researchers tested whether cell phone radiation affects the brain's ability to automatically detect changes in sounds by measuring brain waves in 17 healthy adults while a GSM phone was placed next to their ear. They found no differences in brain responses whether the phone was on or off, suggesting that acute exposure to cell phone radiation doesn't impair this basic auditory processing function. This study adds to research examining how electromagnetic fields might affect brain function during everyday phone use.

Brain & Nervous SystemNo Effects Found

Preattentive auditory information processing under exposure to the 902 MHz GSM mobile phone electromagnetic field: A mismatch negativity (MMN) study

Kwon MS et al. · 2009

Researchers recorded mismatch negativity responses to duration, intensity, frequency, and gap changes in 17 healthy young adults while a GSM phone was placed on either ear with the field on or off. The mismatch negativity was elicited by all deviant types, but its amplitude and latency showed no significant differences due to EMF exposure for any deviant type. The authors concluded there was no conclusive evidence that acute GSM mobile phone EMF exposure affects cortical auditory change detection processing reflected by the mismatch negativity.

The effect of pulsed electromagnetic radiation from mobile phone on the levels of monoamine neurotransmitters in four different areas of rat brain

Aboul Ezz HS, Khadrawy YA, Ahmed NA, Radwan NM, El Bakry MM · 2013

Researchers investigated the effect of electromagnetic radiation on concentrations of dopamine, norepinephrine, and serotonin in the hippocampus, hypothalamus, midbrain, and medulla oblongata of adult rats. Adult rats were exposed daily to electromagnetic radiation at 1800 MHz, with a specific absorption rate of 0.843 W/kg and power density of 0.02 mW/cm2, modulated at 217 Hz. Measurements were taken after 1, 2, and 4 months of daily exposure, and also after stopping exposure for 1 month following 4 months of daily exposure. The exposure resulted in significant changes in dopamine, norepinephrine, and serotonin in all four brain areas studied.

The effect of pulsed electromagnetic radiation from mobile phone on the levels of monoamine neurotransmitters in four different areas of rat brain.

Aboul Ezz HS, Khadrawy YA, Ahmed NA, Radwan NM, El Bakry MM. · 2013

Researchers exposed rats to cell phone radiation (1800 MHz, similar to 2G networks) for up to 4 months and measured key brain chemicals called neurotransmitters that control mood, memory, and learning. The radiation significantly altered levels of dopamine, serotonin, and norepinephrine across four different brain regions. These chemical changes could explain why some people report memory problems, learning difficulties, and increased stress after heavy cell phone use.

Cell Phone Generated Radio Frequency Electromagnetic Field Effects on the Locomotor Behaviors of the Fishes Poecilia reticulata and Danio rerio.

Lee D, Lee J, Lee I. · 2015

Researchers tracked the movement of 10 pairs of guppies and 15 pairs of zebrafish in a fish tank under a cell phone-generated RF EMF. Fish locomotion was observed under normal conditions, in the visual presence of a cell phone, after feeding, and under starvation. Fish locomotor behavior was random both in normal conditions and in the presence of an off-signaled cell phone, but there were significant changes in locomotion after feeding under the RF EMF. The researchers also demonstrated that temperature elevation caused by the cell phone was not relevant to the observed effects.

The alteration of spontaneous low frequency oscillations caused by acute electromagnetic fields exposure

Lv B, Chen Z, Wu T, Shao Q, Yan D, Ma L, Lu K, Xie Y. · 2013

Eighteen subjects participated in a double-blind, crossover, randomized and counterbalanced experiment including real and sham exposure sessions. Resting-state fMRI signals were collected before and after exposure, with the radiation source placed close to the right ear. After real exposure, decreased ALFF values were found in the left superior temporal gyrus, left middle temporal gyrus, right superior temporal gyrus, right medial frontal gyrus, and right paracentral lobule.

Reproductive Health164 citations

Effects of Radiofrequency Electromagnetic Wave Exposure from Cellular Phones on the Reproductive Pattern in Male Wistar Rats.

Kesari KK, Kumar S, Behari J. · 2011

The study investigated the effect of mobile phone exposure on fertility-related markers in 70-day-old male Wistar rats. Rats were exposed in Plexiglas cages for 2 hours a day for 35 days, with a specific absorption rate estimated at 0.9 W/kg. In exposed rats, antioxidant enzymes glutathione peroxidase and superoxide dismutase decreased, while malondialdehyde and free radical generation increased significantly. The researchers concluded that radiofrequency electromagnetic waves from commercially available cell phones might affect the fertilizing potential of spermatozoa.

900-MHz microwave radiation promotes oxidation in rat brain

Kesari KK, Kumar S, Behari J. · 2011

Researchers exposed 35-day old Wistar rats to a mobile phone for 2 hours per day for 45 days at a specific absorption rate of 0.9 W/Kg. Animals were divided into a sham exposed group and an exposed group, each with 6 animals. The exposed group showed a significant decrease in glutathione peroxidase and superoxide dismutase, and a significant increase in reactive oxygen species. The researchers concluded that these findings on biomarkers are clear indications of possible health implications.

Mobile phone usage and male infertility in Wistar rats.

Kesari KK, Kumar S, Behari J. · 2010

Researchers exposed male Wistar rats to mobile phone frequencies at 0.9 W/kg specific absorption rate for 2 hours per day over 35 days. A significant decrease in protein kinase C and total sperm count, along with increased apoptosis, were observed in the exposed rats. The results suggest that a reduction in protein kinase activity may be related to overproduction of reactive oxygen species under microwave field exposure.

Upregulation of Specific mRNA Levels in Rat Brain After Cell Phone Exposure

Yan JG, Agresti M, Zhang LL, Yan Y, Matloub HS. · 2008

Researchers exposed adult Sprague-Dawley rats to cell phones for 6 hours per day for 126 days and measured mRNA levels of several injury-associated proteins in the brain. The proteins evaluated included Calcium ATPase, Neural Cell Adhesion Molecule, Neural Growth Factor, and Vascular Endothelial Growth Factor. The results showed statistically significant mRNA up-regulation of these proteins in the brains of exposed rats.

Cancer & TumorsNo Effects Found

TP53 tumor suppressor protein in normal human fibroblasts does not respond to 837 MHz microwave exposure.

Li et al. · 1999

Researchers exposed human fibroblast cells to 837 MHz continuous microwaves for 2 hours at SAR levels of 0.9 or 9.0 W/kg. TP53 protein levels were measured by Western blot at 2, 8, 24, and 48 hours after exposure. No significant changes in TP53 protein expression were found in exposed cells compared to sham or untreated cells at any time point. No morphological alterations were observed in microwave-treated cells compared to sham-treated cells.

Effects of cell phone radiofrequency signal exposure on brain glucose metabolism

Volkow ND et al. · 2011

Researchers used positron emission tomography to measure brain glucose metabolism in 47 healthy participants, once with the right cell phone activated for 50 minutes and once with both cell phones deactivated. Whole-brain metabolism did not differ between the on and off conditions, but metabolism in the region closest to the antenna was significantly higher in the on condition than the off condition. The researchers noted that this finding is of unknown clinical significance.

CardiovascularNo Effects Found

Effects of 900 MHz electromagnetic field emitted by cellular phones on electrocardiograms of guinea pigs

Meral I, Tekintangac Y, Demir H · 2014

Researchers used 30 healthy guinea pigs weighing 500-800 g, randomly assigning 10 to a control group and 20 to an EMF-exposed group after a one-week adaptation period. The exposed group received 890-915 MHz EMF with a 217 Hz pulse rate, 2 W maximum peak power, and 0.95 wt kg(-1) specific absorption rate for 12 h per day (11 h 45 min stand-by and 15 min speaking mode) over 30 days. ECGs were recorded at baseline and on days 10, 20, and 30 using leads I, II, III, aVR, aVL, and aVF, with wave durations and amplitudes measured in lead II. The authors recommended further investigation with longer exposure durations to clarify cardiovascular effects.

The effect of mobile phone on the number of Purkinje cells: A stereological study.

Rağbetlı MC et al. · 2010

Researchers exposed pregnant mice to mobile phone radiation at levels similar to what humans experience (0.95 W/kg SAR) and found a significant decrease in Purkinje cells in the developing cerebellum of offspring. Purkinje cells are critical neurons that control movement, balance, and coordination. This study suggests that prenatal exposure to mobile phone radiation may affect brain development in areas responsible for motor function.

Induction of oxidative stress in male rats subchronically exposed to electromagnetic fields at non-thermal intensities.

Achudume A, Onibere B, Aina F, Tchokossa P. · 2010

Researchers exposed rats to cell phone radiation (900 MHz and 1800 MHz) for 40 or 60 days. While 40 days showed no effects, 60 days significantly weakened the animals' antioxidant defenses and altered cellular chemistry, suggesting prolonged exposure may overwhelm natural protection against cellular damage.

Effects of mobile phone use on brain tissue from the rat and a possible protective role of vitamin C - a preliminary study.

Imge EB, Kiliçoğlu B, Devrim E, Cetin R, Durak I · 2010

Forty female rats were divided into four groups: control, mobile phone, mobile phone plus vitamin C, and vitamin C alone. The mobile phone groups were exposed to a mobile phone signal (900 MHz), and vitamin C was administered orally for four weeks. Mobile phone exposure caused an inhibition in 5'-NT and CAT activities compared to the control group, while GSH-Px activity and MDA levels were reduced but not significantly. The researchers suggested that vitamin C may play a protective role against detrimental effects of mobile phone radiation in brain tissue.

The effect of mobile phone on the number of Purkinje cells: a stereological study

Rağbetli MC et al. · 2010

Researchers investigated the effect of mobile phone exposure on Purkinje and granule neurons in the developing cerebellum. Pregnant Swiss albino mice were exposed to GSM mobile phone radiation at 890–915 MHz at 0.95 W/Kg specific absorption rate (SAR). The study found a significant decrease in the number of Purkinje cells and a tendency for granule cells to increase.