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

Immune SystemNo Effects Found

Early life exposure to 2.45GHz WiFi-like signals: effects on development and maturation of the immune system

Sambucci M et al. · 2011

Italian researchers exposed newborn mice to WiFi-like signals (2.45 GHz) for 5 weeks during early development to see if young immune systems are more vulnerable to wireless radiation. They found essentially no effects on immune system development at either low (0.08 W/kg) or high (4 W/kg) exposure levels, with only one minor change in male mice at the higher level. The study suggests that developing immune systems may not be as sensitive to WiFi radiation as some have theorized.

Cellular EffectsNo Effects Found

2-GHz band CW and W-CDMA modulated radiofrequency fields have no significant effect on cell proliferation and gene expression profile in human cells.

Sekijima M et al. · 2010

Japanese researchers exposed human brain cells and lung cells to 2.1 GHz radiofrequency radiation (similar to 3G cell phones) for up to 96 hours at various power levels. They found no significant changes in cell growth, survival, or gene expression patterns compared to unexposed cells. The study suggests that RF exposure within current safety guidelines doesn't trigger obvious cellular stress responses in laboratory conditions.

Computational dosimetry in embryos exposed to electromagnetic plane waves over the frequency range of 10 MHz-1.5 GHz.

Kawai H, Nagaoka T, Watanabe S, Saito K, Takahashi M, Ito K. · 2010

Scientists used computer models to study how much electromagnetic radiation developing embryos absorb from radio frequencies. They found embryos absorbed up to 0.08 watts per kilogram when exposed to current safety guideline levels, helping researchers understand potential effects from everyday wireless devices.

Cellular EffectsNo Effects Found

2-GHz Band CW and W-CDMA modulated radiofrequency fields have no significant effect on cell proliferation and gene expression profile in human cells.

Takeda H et al. · 2010

Researchers exposed three types of human cells to 2.1 GHz radiofrequency radiation (similar to 3G cell phone signals) for up to 96 hours at various power levels. They found no significant effects on cell growth, survival, or gene activity compared to unexposed cells. The study suggests that RF exposure at levels within current safety guidelines doesn't cause immediate cellular stress or damage.

Reproductive HealthNo Effects Found

Effects of radiofrequency electromagnetic fields (UMTS) on reproduction and development of mice: A Multi-generation Study

Sommer et al. · 2009

Researchers exposed mice to cell phone radiation (UMTS signals at 1966 MHz) continuously for their entire lives across four generations to study effects on reproduction and development. They found no harmful effects on fertility, pup development, or reproductive health, even at exposure levels up to 1.3 W/kg SAR. The only minor finding was some changes in food consumption patterns without a clear dose-response relationship.

Proportion-corrected scaled voxel models for Japanese children and their application to the numerical dosimetry of specific absorption rate for frequencies from 30 MHz to 3 GHz

Nagaoka T, Kunieda E, Watanabe S · 2008

Japanese scientists created computer models of children's bodies to study how radiofrequency radiation from cell phones and WiFi affects kids differently than adults. They found children's smaller size and body proportions change how much electromagnetic energy they absorb, highlighting potential increased vulnerability.

Cancer & TumorsNo Effects Found

Mobile phone base station radiation does not affect neoplastic transformation in BALB/3T3 cells.

Hirose H et al. · 2008

Researchers exposed mouse cells to radiofrequency radiation from mobile phone base stations for six weeks to see if it would cause cancerous changes. Even at high exposure levels (800 mW/kg), the radiation did not increase the rate of cell transformation into cancer cells. This suggests that base station radiation at these levels doesn't directly promote tumor formation in laboratory conditions.

Whole Body / GeneralNo Effects Found

Effects of mobile phone electromagnetic fields at nonthermal SAR values on melatonin and body weight of Djungarian hamsters (Phodopus sungorus).

Lerchl A et al. · 2008

German researchers exposed hamsters to cell phone radiation 24 hours a day for 60 days at levels matching the maximum allowed for humans. While melatonin levels (the sleep hormone) remained unchanged, hamsters exposed to certain frequencies gained up to 6% more body weight than unexposed animals, suggesting the radiation may affect metabolism even at supposedly safe levels.

Cellular EffectsNo Effects Found

Mobile phone base station‐emitted radiation does not induce phosphorylation of Hsp27

Hirose H et al. · 2007

Researchers exposed human brain and lung cells to cell phone tower radiation at levels up to 10 times higher than public safety limits to test whether it triggers heat shock proteins (cellular stress markers). After continuous exposure for up to 48 hours, they found no increase in these stress proteins compared to unexposed cells. This suggests that cell phone tower radiation at these levels doesn't cause detectable cellular stress responses.

Cellular EffectsNo Effects Found

Mobile phone base station-emitted radiation does not induce phosphorylation of Hsp27.

Hirose H et al. · 2007

Japanese researchers exposed human brain and lung cells to radiofrequency radiation at levels similar to cell tower emissions (2.1 GHz) for up to 48 hours. They found no changes in heat shock proteins (cellular stress markers that increase when cells are damaged) even at exposure levels 10 times higher than public safety limits. This suggests that cell tower-level RF radiation does not trigger detectable cellular stress responses in laboratory conditions.

DNA & Genetic DamageNo Effects Found

DNA strand breaks are not induced in human cells exposed to 2.1425 GHz band CW and W-CDMA modulated radiofrequency fields allocated to mobile radio base stations.

Sakuma N et al. · 2006

Researchers exposed human brain and lung cells to 2.1425 GHz radiofrequency radiation at levels up to 10 times higher than public safety limits for up to 24 hours. They found no DNA damage in either cell type, even at the highest exposure levels tested. This suggests that cell phone tower radiation at these frequencies doesn't break DNA strands under laboratory conditions.

DNA & Genetic DamageNo Effects Found

Phosphorylation and gene expression of p53 are not affected in human cells exposed to 2.1425 GHz band CW or W-CDMA modulated radiation allocated to mobile radio base stations.

Hirose H et al. · 2006

Researchers exposed human brain and lung cells to radiofrequency radiation at 2.14 GHz (similar to cell tower frequencies) for up to 48 hours to see if it would trigger cell death or DNA damage responses. They tested exposure levels from 0.08 to 0.8 watts per kilogram - with the lowest level matching international safety limits for public exposure. The study found no evidence that this RF radiation caused cells to die, damaged DNA, or activated stress response pathways even at levels 10 times higher than safety guidelines.

CardiovascularNo Effects Found

Membrane potential and currents of isolated heart muscle cells exposed to pulsed radio frequency fields.

Linz et al. · 1999

German researchers exposed isolated heart muscle cells from guinea pigs and rats to cell phone frequencies (900 MHz and 1800 MHz) to see if radio waves affected the cells' electrical activity. They found no significant changes to the heart cells' membrane potential, action potentials, or calcium and potassium currents even at exposure levels up to 880 mW/kg. The study suggests that cell phone radiation at these levels does not directly disrupt the basic electrical functions of heart muscle cells.

Effect of 900-, 1800-, and 2100-MHz radiofrequency radiation on DNA and oxidative stress in brain

Alkis ME et al. · 2019

Turkish researchers exposed rats to cell phone radiation at three different frequencies (900, 1800, and 2100 MHz) for 2 hours daily over 6 months to study brain effects. They found increased DNA damage and oxidative stress in brain tissue across all frequency groups compared to unexposed control rats. This suggests that chronic exposure to the radiofrequency radiation emitted by mobile phones may harm brain cells at the genetic level.

Modulation of heat shock protein response in SH-SY5Y by mobile phone microwaves

Calabrò E et al. · 2012

Italian researchers exposed human brain cells to cell phone radiation at 1800 MHz for 2-4 hours and measured stress protein responses. They found that the radiation triggered cellular stress responses in the neurons, specifically decreasing one protective protein (Hsp20) and increasing another (Hsp70) after longer exposure. This suggests that cell phone radiation can activate stress pathways in brain cells even at levels considered safe by current standards.

Impact of radio frequency electromagnetic radiation on DNA integrity in the male germline.

Aitken RJ, Bennetts LE, Sawyer D, Wiklendt AM, King BV. · 2005

Researchers exposed mice to cell phone-level radiation (900 MHz) for 12 hours daily over a week and examined sperm DNA for damage. While the mice appeared healthy and sperm counts looked normal, detailed genetic analysis revealed significant DNA damage in both the mitochondria (cellular powerhouses) and nuclear DNA of sperm cells. This suggests that radiofrequency radiation can harm genetic material in reproductive cells even when other measures appear normal.

Immunohistopathologic demonstration of deleterious effects on growing rat testes of radiofrequency waves emitted from conventional Wi-Fi devices

Atasoy HI, Gunal MY, Atasoy P, Elgun S, Bugdayci G · 2013

Researchers exposed young male rats to Wi-Fi radiation (2.4 GHz) 24 hours a day for 20 weeks and found significant DNA damage in their reproductive organs. The Wi-Fi exposure caused increased markers of genetic damage and reduced the activity of protective enzymes that normally defend against cellular harm. These findings suggest that chronic Wi-Fi exposure during development may threaten reproductive health and fertility.

Superposition of an incoherent magnetic field inhibited EGF receptor clustering and phosphorylation induced by a 1.8 GHz pulse-modulated radiofrequency radiation.

Sun W, Shen X, Lu D, Lu D, Chiang H · 2013

Researchers exposed human cells to 1.8 GHz radiofrequency radiation (similar to cell phone signals) and found it triggered abnormal clustering and activation of cellular receptors that control cell growth. Interestingly, when they added a weak 'noise' magnetic field alongside the RF exposure, it completely blocked these cellular changes at moderate power levels, suggesting the magnetic field provided some protection against RF-induced cellular disruption.

Melatonin modulates wireless (2.45 GHz)-induced oxidative injury through TRPM2 and voltage gated Ca(2+) channels in brain and dorsal root ganglion in rat.

Nazıroğlu M et al. · 2012

Researchers exposed rats to 2.45 GHz radiation (the same frequency used in WiFi and microwave ovens) for one hour daily over 30 days and found it caused brain damage including increased calcium levels in neurons, oxidative stress, and abnormal brain wave patterns. However, when rats were given melatonin supplements, these harmful effects were significantly reduced, suggesting melatonin may protect against WiFi radiation damage to the brain and nervous system.

A 1.8-GHz radiofrequency radiation induces EGF receptor clustering and phosphorylation in cultured human amniotic (FL) cells. Int J Radiat Biol. 88(3):239-244, 2012.

Sun W, Shen X, Lu D, Fu Y, Lu D, Chiang H · 2012

Cell phone radiation (1.8 GHz) activated growth receptors in human cells after just 15 minutes of exposure. The effects occurred at radiation levels of 0.5 W/kg and higher but not at 0.1 W/kg, showing radiofrequency radiation can directly trigger cellular responses that control cell growth and communication.

Modulator effects of L-carnitine and selenium on wireless devices (2.45 GHz)-induced oxidative stress and electroencephalography records in brain of rat

Naziroğlu M, Gümral N. · 2009

Researchers exposed rats to WiFi-frequency radiation (2.45 GHz) for one hour daily over four weeks. The radiation significantly reduced protective antioxidant vitamins A, C, and E in brain tissue. This suggests wireless devices may deplete the brain's natural defenses against cellular damage.

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.