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

Effect of global system for mobile communication microwave exposure on the genomic response of the rat brain.

Fritze K et al. · 1997

Researchers studied the effect of GSM microwave exposure on gene activity in the rat brain by measuring messenger RNAs of hsp70, c-fos, c-jun, and GFAP using in situ hybridization histochemistry. The study used specific absorption rates of 0.3 W/kg, 1.5 W/kg, and 7.5 W/kg. Immediately after exposure, slight hsp70 messenger RNA induction was found in the cerebellum and hippocampus at 7.5 W/kg, but not at lower intensities. At 24 hours and seven days after exposure, no lasting protein changes, altered glial marker expression, or increased cell proliferation were observed.

Effects of cell phone radiation on lipid peroxidation, glutathione and nitric oxide levels in mouse brain during epileptic seizure

Esmekaya MA et al. · 2016

Researchers studied whether cellular phone radiation affects oxidative stress and nitric oxide levels in mouse brain during epileptic seizures induced by pentylenetetrazole (PTZ). Eight-week-old mice were divided into groups: a PTZ-only control group, a group exposed to 15 minutes of radiation before and 30 minutes after PTZ treatment, and a group exposed to 30 minutes of radiation before and 30 minutes after PTZ treatment. Lipid peroxidation and nitric oxide levels increased significantly in the radiation-exposed groups compared to the control group, while glutathione levels were significantly lower in those same groups.

Evaluation of the cytogenotoxic damage in immature and mature rats exposed to 900 MHz radio frequency electromagnetic fields.

Atlı Şekeroğlu Z, Akar A, Sekeroğlu V. · 2013

Researchers investigated the cytogenotoxic effects of 900 MHz radiofrequency electromagnetic fields on bone marrow cells of immature and mature rats. Rats in the treatment groups were exposed to RF-EMF for 2 hours per day for 45 days. Significant differences were observed in chromosome aberrations, micronucleus frequency, mitotic index, and ratio of polychromatic erythrocytes in all treatment and recovery groups. A 15-day recovery period after exposure did not reduce the damage to the same extent as the corresponding control groups.

Thermophysiological responses of human volunteers during controlled whole-body radio frequency exposure at 450 MHz.

Adair ER, Kelleher SA, Mack GW, Morocco TS, · 1998

Thermoregulatory responses of heat production and heat loss were measured in seven adult volunteers (four women and three men, aged 21–57 years) during 45-minute dorsal exposures of the whole body to 450 MHz continuous wave RF fields. Two power densities were tested at each of three ambient temperatures (24, 28, and 31 °C), plus control conditions with no RF. No changes in metabolic heat production occurred, and deep body temperature was regulated to within 0.1 °C of the normal level through vigorous increases in sweating rate on the back and chest.

Cancer & TumorsNo Effects Found

The effect of chronic exposure to 835.62 MHz FDMA or 847.74 MHz CDMA radiofrequency radiation on the incidence of spontaneous tumors in rats.

La Regina M et al. · 2003

Eighty male and 80 female rats were randomly placed in each of three irradiation groups: sham, 835.62 MHz FDMA, and 847.74 MHz CDMA, with exposure 4 hours per day, 5 days per week for 2 years. There were no significant differences in final body weights or survival days between groups, and no significant differences in any tumor incidence between treated and sham-exposed animals. The researchers concluded that chronic exposure to 835.62 MHz FDMA or 847.74 MHz CDMA RF radiation had no significant effect on spontaneous tumor incidence in F344 rats.

Effects of microwave exposure and Gemcitabine treatment on apoptotic activity in Burkitt's lymphoma (Raji) cells.

Canseven AG, Esmekaya MA, Kayhan H, Tuysuz MZ, Seyhan N. · 2014

Raji cells were exposed to microwave radiation at a specific absorption rate of 0.350 W/kg for 24 hours. Microwave exposure alone significantly increased apoptotic activity and significantly decreased cell viability, and combined exposure with Gemcitabine increased apoptotic cells further than microwave radiation alone.

Erythropoietic dynamic equilibrium in rats maintained after microwave irradiation.

Trosic I, Busljeta I. · 2006

Researchers exposed rats to 2.45 GHz microwave radiation at a whole-body SAR of 1.25+/-0.36 W/kg for 2 hours per day, 7 days a week. Bone marrow polychromatic erythrocytes increased on days 8 and 15, and peripheral blood polychromatic erythrocytes increased on days 2 and 8. Bone marrow micronucleated PCE frequency increased on day 15, and peripheral blood micronucleated PCEs increased on day 8, but all values declined nearly to control levels by the end of the experiment.

Cytotoxic and genotoxic effects of high-frequency electromagnetic fields (GSM 1800 MHz) on immature and mature rats

Sekeroğlu V, Akar A, Sekeroğlu ZA · 2012

Researchers investigated the cytogenotoxic effects of 1800 MHz electromagnetic fields on bone marrow cells of immature and mature rats over 45 days with a 15-day recovery period. Significant differences were observed in chromosome aberrations, micronucleus frequency, mitotic index, and polychromatic erythrocyte ratio in all treatment groups. A 15-day recovery period did not improve the cytogenotoxic damage in immature rats.

Brain & Nervous SystemNo Effects Found

No influence on selected parameters of human visual perception of 1970 MHz UMTS-like exposure.

Schmid G, Sauter C, Stepansky R, Lobentanz IS, Zeitlhofer J · 2005

Researchers exposed 58 healthy volunteers to a generic 1.97 GHz UMTS-like signal in a double-blinded crossover design. Each subject completed four clinical visual perception tests under high exposure, low exposure, and sham conditions. High exposure produced an average SAR of 0.63 W/kg (1 g) and 0.37 W/kg (10 g) in the left temporal cortex. No statistically significant differences in visual perception parameters were found between any exposure condition and sham.

Mobile phone radiation-induced free radical damage in the liver is inhibited by the antioxidants n-acetyl cysteine and epigallocatechin-gallate.

Ozgur E, Güler G, Seyhan N. · 2010

Researchers exposed guinea pigs to an 1800-MHz GSM-modulated signal at a whole body SAR of 0.38 W/kg for 10 or 20 minutes per day for seven days to study oxidative damage in the liver. After exposure, significant increases in malondialdehyde and total nitric oxide levels were observed, along with decreases in several antioxidant enzyme activities in the liver. The extent of oxidative damage was found to be proportional to the duration of exposure, and both NAC and EGCG were found to protect liver tissue against this damage.

The Effects of N-acetyl-L-cysteine and Epigallocatechin-3-gallate on Liver Tissue Protein Oxidation and Antioxidant Enzyme Levels After the Exposure to Radio Frequency Radiation.

Ozgur E et al. · 2015

Scientists exposed guinea pigs to cell phone radiation (900 MHz) for seven days and found it significantly reduced SOD, a protective antioxidant enzyme in liver tissue. Surprisingly, two common antioxidant supplements caused cellular damage when used alone, showing radiation's complex effects on cellular protection.

Microwave effect on diffusion: a possible mechanism for non-thermal effect.

Hinrikus H, Lass J, Karai D, Pilt K, Bachmann M. · 2014

Researchers tested whether microwave radiation could affect how a salt solution diffuses through water at constant temperature. The setup used two reservoirs, one filled with pure water and one with 0.9% NaCl solution, connected by a thin tube, with a 450 MHz continuous-wave microwave field applied at a maximal specific absorption rate of 0.4 W/kg on the connecting tube. Microwave exposure made the diffusion process faster, with the time required for a 10% reduction in initial resistance of the solution being 1.7 times shorter with microwave exposure.

Nonthermal Effects of Lifelong High-Frequency Electromagnetic Field Exposure on Social Memory Performance in Rats.

Schneider J, Stangassinger M · 2014

Researchers exposed male and female rats continuously to either 900-MHz GSM or 1.966-GHz UMTS electromagnetic fields at 0.4 W/kg. Memory was assessed using a social discrimination procedure, with differences in sniffing duration to familiar and novel juvenile rats used as the measure. EMF-exposed females showed no differences in sniffing duration compared with controls, but sniffing durations of EMF-exposed males at 3 months of age were significantly affected. At 6 months of age, GSM-exposed male adults showed a memory performance deficit, but UMTS-exposed males did not.

The Effects of N-acetyl-L-cysteine and Epigallocatechin-3-gallate on Liver Tissue Protein Oxidation and Antioxidant Enzyme Levels After the Exposure to Radio Frequency Radiation.

Ozgur E et al. · 2014

Researchers exposed adult male guinea pigs to GSM-modulated radio frequency radiation at an average whole body SAR of 0.4 W/kg for 10 or 20 minutes daily for seven consecutive days. The study measured protein oxidation, advanced oxidation protein products, and superoxide dismutase activity in liver tissue, and also tested NAC and EGCG as potential protective treatments. SOD activity significantly decreased after radio frequency radiation exposure, but protein damage did not change. NAC treatment alone increased PCO levels, and EGCG treatment alone elevated AOPP levels.

Oxidative stress induced by 1.8 GHz radio frequency electromagnetic radiation and effects of garlic extract in rats.

Avci B, Akar A, Bilgici B, Tunçel ÖK. · 2012

Researchers exposed rats to 1.8 GHz radiofrequency radiation (similar to cell phone frequencies) for one hour daily over three weeks at levels comparable to phone use. The radiation caused protein damage in brain tissue and increased nitric oxide levels in blood, indicating oxidative stress. When rats were given garlic extract alongside the radiation exposure, the brain protein damage was significantly reduced.

Oxidative stress induced by 1.8 GHz radio frequency electromagnetic radiation and effects of garlic extract in rats.

Avci B, Akar A, Bilgici B, Tunçel ÖK · 2012

Researchers divided 66 albino Wistar rats into three groups to study oxidative damage from radiofrequency electromagnetic radiation and whether garlic extract could protect against it. After radiofrequency exposure, advanced oxidation protein product levels in brain tissue increased compared with the control group. Garlic administration alongside radiofrequency exposure significantly reduced those protein oxidation levels in brain tissue. No significant differences were found among the groups for malondialdehyde levels in brain tissue and blood, or for serum paraoxonase levels.

Reactive Oxygen Species Formation and Apoptosis in Human Peripheral Blood Mononuclear Cell Induced by 900 MHz Mobile Phone Radiation

Lu YS, Huang BT, Huang YX. · 2012

Researchers studied reactive oxygen species (ROS) formation and apoptosis in human peripheral blood mononuclear cells (PBMC) exposed to 900 MHz radiofrequency electromagnetic fields at a specific absorption rate of ~0.4 W/kg. ROS was found to play an important role in apoptosis when exposure lasted longer than two hours, with apoptosis induced through the mitochondrial pathway and mediated by activating ROS and caspase-3, and decreasing the mitochondrial potential. The imbalance between antioxidant defenses and ROS formation was associated with about 37% human PBMC death in eight hours.

Reproductive Health469 citations

Mobile Phone Radiation Induces Reactive Oxygen Species Production and DNA Damage in Human Spermatozoa In Vitro.

De Iuliis GN, Newey RJ, King BV, Aitken RJ. · 2009

Researchers exposed human sperm to cell phone radiation at 1.8 GHz frequencies. Higher radiation levels reduced sperm movement and survival while increasing DNA damage and harmful molecules. The findings suggest that heavy mobile phone use could potentially affect male fertility and future children's health.

Reproductive Health464 citations

Mobile phone radiation induces reactive oxygen species production and DNA damage in human spermatozoa in vitro.

De Iuliis GN, Newey RJ, King BV, Aitken RJ. · 2009

Researchers exposed purified human spermatozoa in vitro to radio-frequency electromagnetic radiation tuned to 1.8 GHz across a range of specific absorption rates from 0.4 W/kg to 27.5 W/kg. As the SAR increased, sperm motility and vitality were significantly reduced, while mitochondrial reactive oxygen species generation and DNA fragmentation were significantly elevated (P<0.001). The researchers also observed highly significant relationships between SAR, the oxidative DNA damage biomarker 8-OH-dG, and DNA fragmentation after exposure.