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

Thermophysiological responses of human volunteers to whole body RF exposure at 220 MHz.

Adair ER et al. · 2005

Researchers measured thermoregulatory responses in six adult volunteers during 45-minute whole-body exposures to 220 MHz radio frequency energy at three power densities and three ambient temperatures. Esophageal temperature showed small changes of no more than 0.35 °C and never exceeded 37.3 °C under any test condition. Vigorous sweating occurred at PD = 12 and 15 mW/cm(2), with sweating levels higher than those observed for equivalent PD at 100 MHz. The researchers concluded that exposed subjects thermoregulate efficiently through increased heat loss responses, particularly sweating.

Neural and behavioral teratological evaluation of rats exposed to ultra-wideband electromagnetic fields.

Cobb BL et al. · 2000

Researchers exposed pregnant rats to UWB electromagnetic fields during gestation days 3-18, with some pups also exposed for 10 days after birth, then evaluated offspring for behavioral, functional, and morphological effects. UWB-exposed pups emitted significantly more stress vocalizations than sham-exposed pups, and the medial-to-lateral length of the hippocampus was significantly longer in UWB-exposed pups than in sham-exposed animals. Researchers noted there does not appear to be a unifying physiological or behavioral relationship among the significant differences observed.

Electromagnetic fields at 2.45 GHz trigger changes in heat shock proteins 90 and 70 without altering apoptotic activity in rat thyroid gland.

Misa Agustiño MJ et al. · 2012

Fifty-four adult female Sprague-Dawley rats were individually exposed to 2.45 GHz radiation for 30 minutes in a GTEM cell at non-thermal SAR levels. Ninety minutes after exposure HSP-90 and HSP-70 decreased significantly at SAR values of 0.046±1.10 W/Kg and 0.104±5.10−3 W/Kg. Twenty-four hours after exposure HSP-90 had partially recovered and HSP-70 had recovered completely. There were few indications of lesions in the glandular structure and signs of apoptosis were negative in all radiated animals.

Analgetic effects of non-thermal GSM-1900 radiofrequency electromagnetic fields in the land snail Helix pomatia.

Nittby H et al. · 2012

Researchers exposed 29 land snails of the strain Helix pomatia to GSM electromagnetic fields at 1900 MHz at 48 mW/kg for 1 hour each, while 29 snails served as sham controls. Before and after exposure, snails were placed on a hot plate and the time until they retracted was measured by two blinded observers. GSM-exposed snails were less sensitive to thermal pain compared to sham controls, indicating a significant analgesia (Mann-Whitney p < 0.001).

Analgetic effects of non-thermal GSM-1900 radiofrequency electromagnetic fields in the land snail Helix pomatia

Nittby H et al. · 2012

Researchers exposed land snails to cell phone radiation at 1900 MHz for one hour and tested their response to heat-induced pain. The exposed snails showed reduced sensitivity to thermal pain compared to unexposed controls, suggesting the radiofrequency radiation acted as a pain reliever. This finding indicates that non-thermal levels of cell phone radiation can alter nervous system responses in living organisms.

Radiofrequency electromagnetic fields (UMTS, 1,950 MHz) induce genotoxic effects in vitro in human fibroblasts but not in lymphocytes.

Schwarz C et al. · 2008

Researchers exposed human cultured fibroblasts and human lymphocyte cultures to 1,950 MHz UMTS electromagnetic fields at specific absorption rates below the safety limit of 2 W/kg. UMTS exposure increased the comet tail factor and induced centromere-negative micronuclei in human cultured fibroblasts in a dose- and time-dependent way. Incubation for 24 hours at a SAR of 0.05 W/kg produced a statistically significant rise in both the comet tail factor and micronuclei (P = 0.02). No UMTS effect was found in lymphocytes, whether unstimulated or stimulated with Phytohemagglutinin. The researchers concluded that UMTS exposure may cause genetic alterations in some but not in all human cells in vitro.

Radiofrequency electromagnetic fields (UMTS, 1,950 MHz) induce genotoxic effects in vitro in human fibroblasts but not in lymphocytes.

Schwarz C et al. · 2008

Researchers exposed human cells to 3G mobile phone radiation (UMTS at 1,950 MHz) at levels well below safety limits to test for DNA damage. They found that certain cells called fibroblasts showed significant genetic damage after exposure, while immune cells called lymphocytes were unaffected. This suggests that 3G radiation can cause DNA damage in some human cell types even at supposedly safe exposure levels.

Effects of continuous and intermittent exposure to RF fields with a wide range of SARs on cell growth, survival, and cell cycle distribution.

Takashima Y et al. · 2006

Researchers exposed cells to radio frequency electromagnetic fields at 2.45 GHz to examine cell growth, survival, and cell cycle distribution across a wide range of specific absorption rates. When cells were exposed to a continuous RF field at SARs from 0.05 to 100 W/kg for 2 h, cellular growth rate, survival, and cell cycle distribution were not affected. At 200 W/kg, the cell growth rate was suppressed and cell survival decreased, and the temperature of the medium rose to 44.1 degrees C. The researchers suggested that the proliferation disorder is caused by the thermal effect.

Frequency-dependent alterations in enolase activity in Escherichia coli caused by exposure to electric and magnetic fields.

Dutta SK, Verma M, Blackman CF · 1994

Researchers exposed Escherichia coli cultures to electric and magnetic fields and measured the activity of enolase, an enzyme being tested clinically for detection of neoplasia. Exposure to a 147 MHz carrier wave amplitude-modulated at 16 Hz enhanced enolase activity by 62%, while modulation at 60 Hz reduced it by 28%. Exposure to 16 Hz fields alone enhanced enolase activity by 59%, while 60 Hz fields alone reduced activity by 24%. Sham exposures and continuous-wave 147 MHz radiation showed no change in enolase activity.

Increased sensitivity of the non-human primate eye to microwave radiation following ophthalmic drug pretreatment.

Kues HA et al. · 1992

Researchers exposed anesthetized monkeys to pulsed 2.45 GHz microwaves after topical treatment with timolol maleate or pilocarpine. Drug pretreatment lowered the power-density threshold for corneal endothelial lesions and increased iris vascular permeability from 10 to 1 mW/cm². Effects occurred at an average SAR of 0.26 W/kg and were confirmed with specular microscopy, fluorescein angiography, and horseradish peroxidase tracer techniques.

Brain & Nervous SystemNo Effects Found

Effects of thirty-minute mobile phone exposure on saccades

Terao Y et al. · 2007

Researchers used a double-blind, counterbalanced crossover design with 10 normal subjects to test saccade performance before and after 30 minutes of mobile phone EMF exposure or sham exposure. They also measured hand reaction time to a visual signal. Saccade task parameters were unchanged after real or sham exposure, except for VGS and MGS latencies which also did not differ between exposure conditions. Hand reaction time shortened with repeated trials similarly for both exposures. The authors concluded that 30 minutes of mobile phone exposure has no significant short-term effect on saccade performance.

Circadian Rhythmicity of Antioxidant Markers in Rats Exposed to 1.8 GHz Radiofrequency Fields.

Cao H, Qin F, Liu X, Wang J, Cao Y, Tong J, Zhao H. · 2015

Researchers exposed rats to cell phone-level radiation for 2 hours daily over 32 days. The radiation disrupted natural 24-hour cycles of antioxidant production, with nighttime exposures causing the biggest drops in protective compounds like melatonin. This suggests RF radiation may interfere with the body's internal clock.

Circadian Rhythmicity of Antioxidant Markers in Rats Exposed to 1.8 GHz Radiofrequency Fields

Cao H, Qin F, Liu X, Wang J, Cao Y, Tong J, Zhao H · 2015

Researchers exposed male Sprague Dawley rats to 1.8 GHz radiofrequency fields at different times of day to study whether circadian rhythms of plasma antioxidants were affected. Six groups of animals were exposed at a power density of 201.7 μW/cm2 and a specific absorption rate of 0.05653 W/kg for 2 hours per day for 32 consecutive days, each at a different time of day, while a seventh group served as sham-exposed controls. The circadian rhythms of melatonin, GSH-Px, and SOD were shifted in exposed rats, with levels significantly decreased when exposure was given at 23 and 3 h GMT. The researchers concluded that there may be adverse effects of radiofrequency exposure on antioxidant function, affecting both daily antioxidant levels and circadian rhythmicity.

Sleep & Circadian RhythmNo Effects Found

No short-term effects of high-frequency electromagnetic fields on the mammalian pineal gland.

Vollrath L, Spessert R, Kratzsch T, Keiner M, Hollmann H · 1997

Researchers exposed male and female Sprague-Dawley rats and Djungarian hamsters to 900 MHz electromagnetic fields at 0.1 to 0.6 mW/cm2, continuous or pulsed at 217 Hz, for 15 min to 6 h. At day or night had no notable short-term effect on pineal melatonin synthesis in male and female Sprague-Dawley rats and Djungarian hamsters. Pineal synaptic ribbon profile numbers (studied in rats only) were likewise not affected The 900 MHz electromagnetic fields, unpulsed or pulsed at 217 Hz, as applied in the present study, have no short-term effect on the mammalian pineal gland.

Reproductive HealthNo Effects Found

Lack of adverse effects of whole-body exposure to a mobile telecommunication electromagnetic field on the rat fetus.

Takahashi S et al. · 2010

Researchers exposed pregnant rats to 2.14 GHz electromagnetic fields for 20 hours per day during gestation and lactation at low and high specific absorption rates. No abnormal findings were observed in the dams, the F1 generation, or the F2 offspring across multiple parameters including growth, organ weights, survival, development, hormonal status, memory function, reproductive ability, embryotoxicity, and teratogenicity. The authors concluded that under their experimental conditions, whole-body exposure to 2.14 GHz for 20 hours per day during gestation and lactation did not cause any adverse effects on pregnancy or the development of rats.

Brain & Nervous SystemNo Effects Found

Effects of UMTS Cellular Phones on Human Hearing: Results of the European Project "EMFnEAR".

Parazzini M et al. · 2009

European researchers exposed 134 healthy young adults to radiofrequency radiation from UMTS mobile phones for 20 minutes and tested their hearing immediately before and after exposure. The study found no measurable effects on hearing function, including hearing thresholds, inner ear responses, or brain processing of sound. This suggests that short-term exposure to cell phone radiation at typical usage levels doesn't immediately impact the auditory system.

Brain & Nervous SystemNo Effects Found

Effects of UMTS cellular phones on human hearing: results of the European project EMFnEAR

Parazzini M et al. · 2009

Participants received 20 minutes of genuine or sham RF exposure at maximum phone output with 69 mW/kg SAR in the cochlea region. Auditory function was measured before and after exposure using hearing thresholds, otoacoustic emissions, and auditory evoked potentials. No consistent pattern of effects was found, and an isolated high-frequency threshold change was not statistically significant after multiple comparison correction. Researchers concluded that short-term UMTS exposure at maximum consumer phone output does not cause measurable immediate auditory effects.

Immune System108 citations

In vitro exposure of human lymphocytes to 900 MHz CW and GSM modulated radiofrequency: studies of proliferation, apoptosis and mitochondrial membrane potential.

Capri M et al. · 2004

Researchers exposed human peripheral blood mononuclear cells (PBMCs) from healthy donors in vitro to a 900 MHz GSM or continuous-wave (CW) radiofrequency field for 1 hour per day for 3 days. The researchers studied mitogen-induced proliferation, cell cycle progression, spontaneous and induced apoptosis, and mitochondrial membrane potential. GSM-exposed cells showed a slight decrease in proliferation at the lowest mitogen concentration and a slight increase in cells with altered phosphatidylserine distribution, but cell cycle phases, mitochondrial membrane potential, and susceptibility to apoptosis were unaffected. When cells were exposed to the CW radiofrequency field, no significant modifications were observed for any of the endpoints studied.

Ultrawide-band electromagnetic pulses induced hypotension in rats.

Lu ST, Mathur SP, Akyel Y, Lee JC · 1999

Researchers exposed male Wistar-Kyoto rats to ultrawide-band electromagnetic pulses at 0.5-kHz and 1-kHz for 6 minutes. They measured cardiovascular functions including heart rate, systolic, mean, and diastolic pressures using a noninvasive tail-cuff sphygmomanometer. Exposure caused a significant decrease in arterial blood pressure that was robust, consistent, and persistent, while heart rate did not change. Cardiovascular functions were evaluated from 45 minutes to 4 weeks after exposure.

Temporal bisection in rats: the effects of high-peak-power pulsed microwave irradiation

Raslear TG, Akyel Y, Bates F, Belt M, Lu ST · 1993

Researchers studied the effects of high-peak-power pulsed microwaves on a time perception and discrimination task in rats. Time perception, response bias, and total trials did not change with power level. Dose-response effects were observed for discriminability, session time, and trial completions (null responses). Exposures used the TEMPO system with 80 nanosecond pulses exceeding 700 megawatts peak power, whole-body SAR of 0.072 W/kg, well below the 0.4 W/kg limit.

Cancer & TumorsNo Effects Found

No effect of short-term exposure to GSM-modulated low-power microwaves on benzo(a)pyrene-induced tumours in rat.

Chagnaud, JL, Moreau, JM, Veyret, B · 1999

Two-month-old female Sprague-Dawley rats were treated by injection of benzo(a)pyrene and irradiated with GSM (Global System for Mobile)-modulated 900-MHz microwaves in an anechoic chamber at 55 or 200 mu W cm-2 (75 and 270mWkg-1 average whole-body SAR, 2h daily for 2 weeks). Microwave exposure had no effect on tumour development, no acceleration or delays in tumour onset were observed, and animal survival was not modified while serum auto-antibody levels were similar in exposed and sham-exposed groups.

Noninvasive Assessment of Metabolic Effects of Exposure to 900 MHz Electromagnetic Fields on Djungarian Hamsters ( Phodopus sungorus).

Taberski K et al. · 2014

Researchers exposed 16 male Djungarian hamsters to 900 MHz GSM-modulated RF-EMF at SAR levels of 0, 0.08, 0.4, and 4 W/kg for one week per condition. Only at the highest SAR level did fur temperature increase by about 0.5°C, food consumption decrease, and daytime carbon dioxide production and respiratory quotient decrease.

Brain & Nervous SystemNo Effects Found

Multigenerational effects of whole body exposure to 2.14 GHz W-CDMA cellular phone signals on brain function in rats

Shirai T et al. · 2014

Researchers exposed rats to 2.14 GHz W-CDMA signals for 20 hours a day over three generations. No abnormalities were observed in mother rats or offspring across any biological parameters including neurobehavioral function. The study used three SAR levels: high (<0.24 W/kg), low (<0.08 W/kg), and sham exposure. Pregnant rats were exposed from gestational day 7 to weaning, and offspring were continuously exposed until 6 weeks of age.

Brain & Nervous SystemNo Effects Found

Multigenerational effects of whole body exposure to 2.14 GHz W-CDMA cellular phone signals on brain function in rats.

Shirai T et al. · 2014

Japanese researchers exposed rats to cell phone radiation (2.14 GHz W-CDMA signals) for 20 hours daily across three generations to see if it affected brain development and behavior. They found no abnormalities in brain function, behavior, or general health in any generation of rats, even with continuous exposure from pregnancy through adulthood. The study suggests that this type of cell phone radiation at these exposure levels does not cause harmful effects that pass from parents to offspring.