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

SAR (Specific Absorption Rate)

Share:

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 the exposure to intermittent 1.8 GHz radio frequency electromagnetic fields on HSP70 expression and MAPK signaling pathways in PC12 cells.

Valbonesi P, Franzellitti S, Bersani F, Contin A, Fabbri E. · 2014

Researchers exposed rat PC12 cells to 1.8 GHz continuous wave or GSM-modulated signals at a SAR of 2 W/kg for 4, 16, or 24 hours. HSP70 gene expression was measured by RT-PCR, while HSP70 protein and MAPK phosphorylation were measured by Western blotting. Only the GSM-217Hz signal increased HSP70 transcription after 16 or 24 hours of exposure. HSP70 protein levels and three MAPK signaling pathways were unchanged by any of the signals.

Mobile Phone Radiation Alters Proliferation of Hepatocarcinoma Cells.

Ozgur E, Guler G, Kismali G, Seyhan N · 2014

Researchers exposed Hep G2 hepatocarcinoma cells to intermittent 900- and 1800-MHz radiofrequency radiation at a specific absorption rate of 2 W/kg for 1, 2, 3, or 4 hours. Cell viability changed according to the frequency and duration of the exposure. Four-hour exposure produced more pronounced effects than shorter durations. 1800-MHz radiation had a larger impact on cell viability and injury than 900-MHz radiation. Morphological analysis showed irregular nuclei and DNA damage after 4 hours of 1800-MHz exposure.

Oxidative changes and apoptosis induced by 1800-MHz electromagnetic radiation in NIH/3T3 cells.

Hou Q, Wang M, Wu S, Ma X, An G, Liu H, Xie F. · 2014

Researchers exposed mouse cells to 1800-MHz cell phone radiation at levels similar to what phones emit during calls (2 W/kg SAR). They found that even intermittent exposure for just one hour significantly increased harmful reactive oxygen species and caused more cells to die through a process called apoptosis. This demonstrates that cell phone radiation can trigger cellular stress and damage at exposure levels considered safe by current regulations.

Effect of a 2.45-GHz radiofrequency electromagnetic field on neutrophil chemotaxis and phagocytosis in differentiated human HL-60 cells.

Koyama S et al. · 2014

Researchers examined the effect of 2.45-GHz radiofrequency fields at SARs of 2 and 10 W/kg for 4 and 24 hours on neutrophil chemotaxis and phagocytosis in differentiated human HL-60 cells. Neutrophil chemotaxis was not affected by radiofrequency field exposure, and phagocytosis was not affected either compared with sham exposure conditions. Exposure at an SAR under 10 W/kg showed very little or no effects on either chemotaxis or phagocytosis.

Differential Pro-Inflammatory Responses of Astrocytes and Microglia Involve STAT3 Activation in Response to 1800 MHz Radiofrequency Fields.

Lu Y et al. · 2014

Researchers exposed microglial N9 and astroglial C8-D1A cells to 1800 MHz radiofrequency fields to study pro-inflammatory responses and the mechanisms involved. Radiofrequency exposure induced different expression and release profiles of inflammatory markers including IL-1β, TNF-α, IL-6, PGE2, nitric oxide, inducible nitric oxide synthase, and cyclooxygenase 2 in the two cell types. STAT3 was activated by radiofrequency exposure in microglia but not in astrocytes, and the STAT3 inhibitor Stattic reduced the release of pro-inflammatory cytokines in microglia but not in astrocytes.

Brain & Nervous SystemNo Effects Found

Effect of whole-body exposure to the 848.5-MHz code division multiple access (CDMA) electromagnetic field on adult neurogenesis in the young, healthy rat brain.

Kim HS et al. · 2014

Researchers assigned male Sprague-Dawley rats to cage-control, sham-exposed, and CDMA-exposed groups, with six rats per group. The CDMA-exposed rats received whole-body exposure to an 848.5 MHz CDMA signal at 2 W/kg for either 1 or 8 hours daily, five days a week, for two weeks. During the last five exposure days, all rats were injected with BrdU to label dividing cells, and the numbers of BrdU-positive cells in the subventricular zone and dentate gyrus were estimated using an unbiased stereological method. The study found no significant difference in BrdU-positive cell counts in either brain region between CDMA-exposed rats and both control groups.

Studying the protein expression in human B lymphoblastoid cells exposed to 1.8-GHz (GSM) radiofrequency radiation (RFR) with protein microarray.

Zhijian C et al. · 2013

The study used protein microarray to examine protein expression in human B lymphoblastoid cells intermittently exposed to 1.8-GHz GSM radiofrequency radiation at a specific absorption rate of 2.0 W/kg for 24 hours. The analysis identified 27 differentially expressed proteins associated with DNA damage repair, apoptosis, oncogenesis, cell cycle, and proliferation, with a fold change greater than 1.5 and P<0.05. Western blot validation confirmed that RPA32 expression was significantly down-regulated and p73 expression was significantly up-regulated in the exposed group (P<0.05).

Cellular EffectsNo Effects Found

Exposure to acute electromagnetic radiation of mobile phone exposure range alters transiently skin homeostasis of a model of pigmented reconstructed epidermis.

Simon D et al. · 2013

Researchers exposed reconstructed epidermis models with and without melanocytes to 900 MHz GSM radiation at 2 mW/g for 6 hours. No changes were observed in epidermal architecture, epidermal markers, apoptotic cells, p53 induction, melanocyte location, dendricity, or melanin transfer after exposure. Loricrin and cytokeratin 14 decreased significantly at 6 hours, but all marker levels increased at 24 hours compared to 6 hours, alongside decreased 20S proteasome activity. The presence or absence of melanocytes did not affect the response of the reconstructed epidermis to exposure.

Oxidative StressNo Effects Found

Effects of combined radiofrequency radiation exposure on levels of reactive oxygen species in neuronal cells.

Kang KA et al. · 2013

Researchers exposed neuronal brain cells to combined cell phone radiation (CDMA and WCDMA signals) for 2 hours to see if it would increase reactive oxygen species (ROS), which are harmful molecules that can damage cells. The study found no increase in ROS levels from the radiation exposure, even when combined with chemicals known to cause oxidative stress. This suggests the specific radiation levels tested did not trigger cellular damage in these lab-grown brain cells.

Sleep EEG alterations: effects of different pulse-modulated radio frequency electromagnetic fields.

Schmid MR et al. · 2012

Thirty young healthy men were exposed, at weekly intervals, for 30 minutes directly before an 8-hour sleep period to a 900-MHz RF EMF pulse-modulated at 14 Hz, at 217 Hz, or to a sham control. EEG power in the spindle frequency range was increased during non-rapid eye movement sleep after the 14-Hz pulse-modulated condition, while a similar but non-significant increase was also observed after the 217-Hz condition. No clear exposure-related effects on cognitive performance were seen, and the exposure-induced effect showed considerable individual variability.

Sleep EEG alterations: effects of pulsed magnetic fields versus pulse‐modulated radio frequency electromagnetic fields

Schmid MR et al. · 2012

Twenty-five young healthy men took part in a randomized double-blind crossover design, exposed at weekly intervals to different conditions for 30 minutes before sleep. The conditions were a 2-Hz pulse-modulated radio frequency field, a 2-Hz pulsed magnetic field, and sham. Radio frequency exposure increased electroencephalogram power in the spindle frequency range. Delta and theta activity during non-rapid eye movement sleep, and alpha and delta activity during rapid eye movement sleep, were affected following both exposure conditions. No effect on sleep architecture and no clear impact of exposure on cognition was observed.

Sleep EEG alterations: effects of pulsed magnetic fields versus pulse-modulated radio frequency electromagnetic fields.

Schmid MR et al. · 2012

Swiss researchers exposed 25 young men to cell phone radiation before sleep and monitored their brain waves overnight. The radiation measurably altered brain activity during sleep, changing specific wave patterns even though exposure lasted only 30 minutes before bedtime, demonstrating electromagnetic fields affect brain function.

Effect of exposure to the edge signal on oxidative stress in brain cell models.

Poulletier de Gannes F et al. · 2011

Researchers exposed three human brain cell lines and primary cortical neurons to the EDGE signal at 1800 MHz. Four exposure conditions were tested: 2 and 10 W/kg for 1 and 24 hours. Reactive oxygen species production was measured by flow cytometry using the DCFH-DA probe. All cells tested responded to rotenone treatment by increasing ROS production. The EDGE signal did not induce oxidative stress under any test condition, including at 10 W/kg.

Cancer & TumorsNo Effects Found

Lymphoma development of simultaneously combined exposure to two radiofrequency signals in AKR/J mice.

Lee HJ et al. · 2011

Six-week-old AKR/J mice were simultaneously exposed to CDMA and WCDMA RF-EMFs for 45 minutes per day, five days per week, for 42 weeks. The whole-body average SAR was 2.0 W/kg for each signal, totaling 4.0 W/kg. No differences were found in final survival, lymphoma incidence, or splenomegaly incidence between sham- and RF-exposed mice. However, brain metastasis infiltration in lymphoma-bearing mice was significantly different in RF-exposed mice compared to sham-exposed mice, with no consistent correlation between sexes. Infiltration to liver, lung, and spleen did not differ between groups.

Whole Body / GeneralNo Effects Found

One-year, simultaneous combined exposure of CDMA and WCDMA radiofrequency electromagnetic fields to rats.

Jin YB, Lee HJ, Seon Lee J, Pack JK, Kim N, Lee YS. · 2011

Researchers exposed two groups of 40 Sprague-Dawley rats to CDMA and WCDMA radiofrequency fields simultaneously at 2.0 W/kg each for 45 minutes per day, five days a week, for one year. No significant alteration in body weight was observed with the combined exposure. Total tumour incidence did not differ between exposed and sham-exposed animals. Most exposed rats showed no significant changes in urinalysis, haematology, blood biochemistry, or histopathology. However, some altered parameters in complete blood count and serum chemistry were seen in exposed rats.

Reproductive HealthNo Effects Found

The effects of simultaneous combined exposure to CDMA and WCDMA electromagnetic fields on rat testicular function.

Lee HJ et al. · 2011

Researchers examined the effects of combined exposure to radiofrequency electromagnetic fields on rat testicular function, specifically spermatogenesis. Male rats were exposed to CDMA and WCDMA RF signals for 12 weeks at 45 minutes per day, 5 days per week, with a whole-body average SAR of 2.0 W/kg each or 4.0 W/kg total. They investigated sperm count, testosterone concentration, malondialdehyde concentrations, spermatogenesis stages, and apoptotic cells in the testes.

Reproductive Health111 citations

The effect of pulsed 900-MHz GSM mobile phone radiation on the acrosome reaction, head morphometry and zona binding of human spermatozoa.

Falzone N, Huyser C, Becker P, Leszczynski D, Franken DR. · 2011

Highly motile human spermatozoa were exposed for 1 hour to 900-MHz mobile phone radiation at a specific absorption rate of 2.0 W/kg and examined at various times after exposure. The radiation did not affect the sperm acrosome reaction, but significant reductions were found in sperm head area and acrosome percentage of the head area among exposed sperm compared with unexposed controls. The mean number of zona-bound sperm was 22.8 in exposed samples versus 31.8 in controls, a statistically significant difference (p < 0.05). The researchers concluded that these results could indicate a significant effect of RF-EMF on sperm fertilization potential.

Oxidative StressNo Effects Found

Effect of Exposure to the Edge Signal on Oxidative Stress in Brain Cell Models

Poulletier de Gannes F et al. · 2011

French researchers exposed human brain cells (neurons, astrocytes, and microglia) to EDGE cell phone signals at 1800 MHz for 1 and 24 hours at high intensities up to 10 W/kg. They measured whether this radiofrequency exposure increased oxidative stress - a type of cellular damage linked to various health problems. The study found no increase in reactive oxygen species production, indicating the EDGE signals did not cause oxidative stress under these conditions.

Electromagnetic field effect or simply stress? Effects of UMTS exposure on hippocampal longterm plasticity in the context of procedure related hormone release.

Prochnow N et al. · 2011

Researchers applied UMTS radio-frequency signals to male Wistar rats at whole-brain SAR levels of 0, 2, and 10 W/kg for 120 minutes. They measured stress hormones corticosterone and ACTH and recorded hippocampal long-term potentiation (LTP) and long-term depression (LTD). Cage exposure increased corticosterone and ACTH levels and was associated with generally decreased LTP and LTD. At 2 W/kg the rats showed no difference from sham in LTP and LTD, while at 10 W/kg a significant reduction in both was observed.

Sleep & Circadian RhythmNo Effects Found

Effects of electromagnetic fields emitted by mobile phones (GSM 900 and WCDMA/UMTS) on the macrostructure of sleep

Danker-Hopfe H, Dorn H, Bahr A, Anderer P, Sauter C · 2011

German researchers exposed 30 young men to cell phone radiation at maximum power levels (2 W/kg SAR) for 8 hours nightly while they slept, testing both older GSM and newer 3G signals. They found no meaningful effects on sleep quality or architecture across multiple measured variables. The study suggests that cell phone radiation at current safety limits doesn't disrupt normal sleep patterns.

CardiovascularNo Effects Found

Analysis of proteome response to the mobile phone radiation in two types of human primary endothelial cells

Nylund R, Kuster N, Leszczynski D · 2010

Researchers exposed primary human umbilical vein endothelial cells and primary human brain microvascular endothelial cells to 1800 MHz GSM radiation for one hour at an average specific absorption rate of 2.0 W/kg. Protein expression patterns were examined immediately after exposure using two dimensional difference gel electrophoresis-based proteomics (2DE-DIGE). Exposure did not cause any statistically significant changes in protein expression in either cell type.

Exposure to 1800 MHz radiofrequency radiation induces oxidative damage to mitochondrial DNA in primary cultured neurons.

Xu S et al. · 2010

Researchers exposed primary cultured cortical neurons to pulsed radiofrequency electromagnetic fields at 1800 MHz modulated by 217 Hz at an average specific absorption rate of 2 W/kg. At 24 hours after exposure, researchers found a significant increase in levels of 8-hydroxyguanine, a common biomarker of DNA oxidative damage, in the mitochondria of neurons. The copy number of mitochondrial DNA and the levels of mitochondrial RNA transcripts showed an obvious reduction after RF exposure. Each of these mitochondrial DNA disturbances could be reversed by pretreatment with melatonin.

Exposure to 1800 MHz radiofrequency radiation induces oxidative damage to mitochondrial DNA in primary cultured neurons

Xu S et al. · 2010

Researchers exposed brain neurons to cell phone-frequency radiation (1800 MHz) at levels similar to heavy phone use and found it damaged the DNA inside cellular powerhouses called mitochondria. The radiation increased markers of DNA damage by 24 hours and reduced the neurons' ability to produce energy. Importantly, the antioxidant melatonin completely prevented this damage, suggesting oxidative stress was the underlying cause.