3,138 Studies Reviewed. 77.4% 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:

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

Showing 871 studies with measured sar (specific absorption rate) exposure

Brain & Nervous SystemNo Effects Found

Effects of weak mobile phone - electromagnetic fields (GSM, UMTS) on event related potentials and cognitive functions.

Kleinlogel H et al. · 2008

Swiss researchers tested whether cell phone radiation from both older GSM and newer UMTS networks affects brain function and cognitive performance in 15 healthy adults. They measured brain wave responses and reaction times during various mental tasks while exposing participants to phone radiation at levels similar to actual phone use (SAR 0.1 and 1 W/kg). The study found no significant changes in any measured brain or cognitive functions compared to fake exposure.

Brain & Nervous SystemNo Effects Found

Effects of weak mobile phone - electromagnetic fields (GSM, UMTS) on well-being and resting EEG.

Kleinlogel H et al. · 2008

Swiss researchers exposed 15 healthy adults to mobile phone signals from both older GSM phones (900 MHz) and newer UMTS phones (1950 MHz) for 30 minutes to see if the radiation affected brain activity or how people felt. Using brain wave monitoring (EEG) and self-reported wellness measures, they found no significant changes compared to fake exposure sessions. This suggests that typical mobile phone radiation levels don't immediately alter brain function or cause noticeable symptoms in healthy users.

Brain & Nervous SystemNo Effects Found

Effects of weak mobile phone - electromagnetic fields (GSM, UMTS) on event related potentials and cognitive functions.

Kleinlogel H et al. · 2008

Researchers tested whether cell phone radiation from GSM and UMTS networks affects brain activity and cognitive performance in 15 healthy adults. They measured brain waves and reaction times during various mental tasks while participants were exposed to phone radiation at levels typical of actual phone use. The study found no significant changes in brain activity or cognitive function during EMF exposure compared to fake (sham) exposure.

DNA & Genetic DamageNo Effects Found

Analysis of gene expression in two human-derived cell lines exposed in vitro to a 1.9 GHz pulse-modulated radiofrequency field.

Chauhan V et al. · 2007

Canadian researchers exposed two types of human cells to 1.9 GHz radiofrequency radiation (similar to cell phone signals) for up to 24 hours at power levels ranging from very low to high. They found no changes in gene expression - meaning the RF exposure didn't turn genes on or off differently than unexposed cells. However, when they heated the same cells to 43°C (109°F) for comparison, multiple heat-shock genes activated as expected.

DNA & Genetic DamageNo Effects Found

Microarray gene expression profiling of a human glioblastoma cell line exposed in vitro to a 1.9 GHz pulse-modulated radiofrequency field.

Qutob SS et al. · 2006

Researchers exposed human brain cancer cells (glioblastoma) to 1.9 GHz radiofrequency radiation for 4 hours at power levels ranging from very low to quite high (0.1 to 10 W/kg SAR). They found no changes in gene expression at any exposure level, while heat treatment successfully triggered expected cellular stress responses. This suggests that RF fields at these levels don't alter how genes function in these particular brain cells.

Modest increase in temperature affects ODC activity in L929 cells: low-level radiofrequency radiation does not.

Hoyto A, Sihvonen AP, Alhonen L, Juutilainen J, Naarala J · 2006

Researchers exposed mouse cells to cell phone-level radiofrequency radiation for 24 hours. The RF radiation itself caused no biological effects, but tiny temperature increases (less than 1°C) significantly affected cellular enzyme activity, showing temperature control is crucial in EMF studies.

Investigation of potential effects of cellular phones on human auditory function by means of distortion product otoacoustic emissions.

Janssen T, Boege P, von Mikusch-Buchberg J, Raczek J. · 2005

Researchers tested whether 900-MHz cell phone radiation affects inner ear hearing cells in 28 people. They found extremely small changes (less than 1 decibel) in some subjects, but concluded these tiny shifts are physiologically meaningless given humans' 120-decibel hearing range.

Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate.

Huber R et al. · 2003

Swiss researchers exposed volunteers to cell phone-level radiation (900 MHz) and monitored their sleep. RF exposure increased brain wave activity in the 9-14 Hz range during deep sleep and altered heart rate patterns, suggesting cell phone radiation affects brain structures that control sleep and heart function.

DNA & Genetic DamageNo Effects Found

Genotoxic Potential of 1.6 GHz Wireless Communication Signal: In Vivo Two-Year Bioassay.

Vijayalaxmi, Sasser LB, Morris JE, Wilson BW, Anderson LE. · 2003

Researchers exposed pregnant rats and their offspring to 1.6 GHz wireless signals (similar to cell phones) for two years, then examined their bone marrow cells for DNA damage. They found no difference in genetic damage between exposed rats and unexposed control rats, with damage rates around 5-6 micronuclei per 2,000 cells in all groups. This suggests that chronic exposure to these wireless signals at the tested levels did not cause detectable DNA damage in the bone marrow.

The effect of low level continuous 2.45 GHz waves on enzymes of developing rat brain.

Paulraj R, Behari J · 2002

Researchers exposed young rats to 2.45 GHz microwave radiation (the same frequency used in WiFi and microwave ovens) for 2 hours daily over 35 days at very low power levels. They found significant changes in brain chemistry, including disrupted calcium levels and altered enzyme activity that controls cell growth and development. The authors concluded these changes could promote tumor development in the developing brain.

DNA & Genetic DamageNo Effects Found

DNA damage and micronucleus induction in human leukocytes after acute in vitro exposure to a 1.9 GHz continuous-wave radiofrequency field

McNamee JP et al. · 2002

Researchers exposed human white blood cells to cell phone radiation (1.9 GHz) for 2 hours at various power levels to see if it would damage DNA or cause genetic abnormalities. They found no evidence of DNA damage or genetic changes at any exposure level tested, including levels 5 times higher than typical cell phone use. This Canadian government study suggests that short-term radiofrequency exposure may not directly harm genetic material in immune cells.

Disruption of a putative working memory task and selective expression of brain c-fos following microwave-induced hyperthermia

Mickley GA, Cobb BL, Mason PA, Farrell S · 1994

Researchers exposed rats to microwave radiation at different power levels and tested their ability to recognize familiar objects versus new ones. Rats exposed to higher levels (above 5 W/kg) showed memory problems and couldn't distinguish between familiar and new objects, while unexposed rats could. The study also found that microwave exposure activated stress response genes in key brain regions including the hypothalamus and amygdala.

Neoplastic transformation of C3H/10T1/2 cells following exposure to 120-Hz modulated 2.45-GHz microwaves and phorbol ester tumor promoter.

Balcer-Kubiczek EK, Harrison GH. · 1991

Researchers exposed mouse cells to microwave radiation (same frequency as WiFi) plus a tumor-promoting chemical. While microwaves alone caused no harm, the combination significantly increased cancer-like cell transformation to levels matching X-ray exposure, suggesting microwaves may promote cancer under certain conditions.

Transient and cumulative memory impairments induced by GSM 1.8 GHz cell phone signal in a mouse model

Ntzouni MP et al. · 2013

Researchers exposed mice to cell phone radiation (GSM 1.8 GHz) for 90 minutes daily to test effects on memory. After weeks of exposure, the mice showed significant problems with both spatial memory (remembering locations) and non-spatial memory (recognizing objects). These memory problems persisted for two weeks after radiation stopped but fully recovered after a month, suggesting the brain can repair this type of damage over time.

Individual differences in the effects of mobile phone exposure on human sleep: Rethinking the problem

Loughran SP, McKenzie RJ, Jackson ML, Howard ME, Croft RJ. · 2012

Australian researchers exposed 20 people to cell phone radiation before sleep and monitored their brain waves. The radiation increased brain activity during deep sleep, but effects varied greatly between individuals. This suggests previous studies may have missed real impacts by averaging results across all participants.

Mutagenic response of 2.45 GHz radiation exposure on rat brain.

Kesari KK, Behari J, Kumar S. · 2010

Researchers exposed rats to 2.45 GHz microwave radiation (the same frequency used in WiFi routers and microwave ovens) for 2 hours daily over 35 days at relatively low power levels. They found significant DNA damage in brain cells, disrupted antioxidant defenses, and changes in proteins that regulate cell division. The authors concluded this chronic exposure pattern may promote brain tumor development.

Reproductive HealthNo Effects Found

Effects of gestational exposure to 1.95‐GHz W‐CDMA signals for IMT‐2000 cellular phones: Lack of embryotoxicity and teratogenicity in rats

Ogawa K et al. · 2009

Researchers exposed pregnant rats to cell phone radiation (1.95-GHz W-CDMA signals) for 90 minutes daily during the critical period of fetal development (days 7-17 of pregnancy). They found no harmful effects on pregnancy outcomes, fetal development, or birth defects at exposure levels up to 2.0 W/kg brain SAR. This suggests that typical cell phone radiation exposure during pregnancy may not cause developmental problems in offspring.

The effect of mobile phone electromagnetic fields on the alpha rhythm of human electroencephalogram.

Croft RJ et al. · 2008

Researchers measured brain waves in 120 people while they used mobile phones for 30 minutes, finding that phone radiation significantly changed the brain's electrical activity patterns. Specifically, the phones increased "alpha waves" (brain rhythms associated with relaxed awareness) more on the side of the head closest to the phone. This study confirms that mobile phone radiation can alter normal brain function in real-time.

Brain & Nervous SystemNo Effects Found

The sensitivity of human event-related potentials and reaction time to mobile phone emitted electromagnetic fields.

Hamblin DL, Croft RJ, Wood AW, Stough C, Spong J. · 2006

Researchers exposed 120 people to mobile phone radiation for 30 minutes while measuring their brain activity and reaction times during cognitive tasks. They found no significant changes in brain function, reaction speed, or electrical brain patterns compared to fake exposure sessions. This contradicts some earlier studies that suggested cell phones might affect how quickly the brain processes information.

Protein Kinase C Activity in developing rat brain cells exposed to 2.45 GHz radiation

Paulraj R, Behari J · 2006

Researchers exposed developing rat brains to 2.45 GHz radiation (the same frequency as WiFi and microwaves) for 2 hours daily over 35 days. They found significant decreases in protein kinase C activity in the hippocampus, a brain region crucial for learning and memory, plus increased glial cells which can indicate brain inflammation. The study suggests that chronic microwave exposure during brain development may interfere with normal growth and cellular function.

Disturbance of cell proliferation in response to mobile phone frequency radiation.

Trosić I, Pavicić I. · 2009

Researchers exposed hamster cells to mobile phone radiation (935 MHz) at low power levels for 1-3 hours and tracked their growth over four days. They found that cells exposed for three hours showed reduced growth 72 hours later and immediate damage to their internal scaffolding structures called microtubules. This suggests that even brief exposures to cell phone-level radiation can disrupt normal cellular function and growth patterns.

No mutagenic or recombinogenic effects of mobile phone fields at 900 MHz detected in the yeast saccharomyces cerevisiae.

Gos P, Eicher B, Kohli J, Heyer WD · 2000

Scientists tested whether 900 MHz mobile phone radiation could damage DNA in yeast cells using multiple genetic tests. They found no evidence of mutations, DNA damage, or cellular dysfunction, even when combined with known toxic chemicals, suggesting these radiation levels may not directly harm genetic material.

Comparison of numerical and experimental methods for determination of SAR and radiation patterns of handheld wireless telephones.

Gandhi OP, Lazzi G, Tinniswood A, Yu QS, · 1999

Researchers compared computer calculations with actual measurements to determine how much radiofrequency energy cell phones deposit in human tissue (called SAR). They tested phones operating at cellular frequencies and found SAR levels ranged dramatically from 0.13 to 5.41 watts per kilogram, with some older-technology phones exceeding current safety limits of 1.6 W/kg unless antennas were carefully designed and positioned away from the head.