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.
Based on Building Biology Institute guidelines (W/kg (watts per kilogram)):
See where common exposures fall on the scale:
Showing 871 studies with measured sar (specific absorption rate) exposure
Megha K et al. · 2015
Researchers exposed rats to cell phone radiation for 30 days and found significant decreases in brain chemicals like dopamine and serotonin that control mood and memory. This suggests wireless device radiation could potentially disrupt how brain cells communicate with each other.
Deshmukh PS et al. · 2015
Researchers exposed rats to low-level microwave radiation at cell phone frequencies (900-2450 MHz) for 6 months and found significant brain damage. The exposed animals showed impaired learning and memory, elevated stress proteins, and DNA damage in brain tissue. These effects occurred at radiation levels thousands of times lower than current safety limits, suggesting chronic exposure to common wireless devices may harm cognitive function.
Deshmukh PS et al. · 2013
Researchers exposed rats to extremely low-level microwave radiation at cell phone frequencies (900, 1800, and 2450 MHz) for two hours daily over 30 days and found DNA damage in brain tissue. The exposure levels were about 1,000 times lower than current safety limits, yet still caused measurable genetic damage. This suggests that even very weak microwave radiation can harm brain cells at the DNA level.
Deshmukh PS et al. · 2016
Researchers exposed rats to cell phone radiation (900 MHz) at extremely low levels for 90 days. The rats developed impaired learning and memory, elevated stress proteins, and DNA damage in brain cells at radiation levels thousands of times below current safety standards.
Deshmukh PS et al. · 2015
Researchers exposed rats to extremely low-intensity microwave radiation at cell phone frequencies (900, 1800, and 2450 MHz) for 180 days and found significant cognitive impairment and DNA damage in brain tissue. The exposure levels were thousands of times lower than current safety limits, yet still caused measurable harm including memory problems and genetic damage. This challenges the assumption that only high-intensity radiation poses health risks.
Deshmukh PS et al. · 2013
Scientists exposed rats to cell phone-level microwave radiation (900 MHz) for 30 days at extremely low power levels. They discovered DNA damage in brain tissue even at exposures thousands of times weaker than current safety limits, suggesting cellular harm may occur below regulatory thresholds.
Megha K et al. · 2012
Researchers exposed rats to cell phone-level microwave radiation (900 MHz) for 2 hours daily over 30 days and found significant brain damage including memory problems, cellular stress, and inflammation. The exposure level was extremely low - about 1,000 times weaker than current safety limits - yet still caused measurable harm to brain tissue. This challenges the assumption that only high-intensity radiation poses health risks.
Megha K et al. · 2012
Researchers exposed rats to cell phone frequency radiation (900 MHz) for 2 hours daily over 30 days and found significant cognitive impairment, brain inflammation, and oxidative stress damage. The rats showed worse memory and learning abilities, along with increased inflammatory markers in their brain tissue. This suggests that chronic exposure to microwave radiation at levels similar to cell phones may harm brain function through cellular damage.
Megha K et al. · 2012
Researchers exposed rats to cell phone-level microwave radiation (900 MHz and 1800 MHz) for 2 hours daily over 30 days and measured brain effects. The exposed rats showed significant cognitive impairment, increased brain inflammation, and oxidative stress (cellular damage from unstable molecules) compared to unexposed rats. This suggests that chronic microwave exposure at levels similar to cell phone use may harm brain function and memory.
Grafström G et al. · 2008
Swedish researchers exposed rats to GSM-900 mobile phone radiation for 2 hours weekly over 55 weeks at very low power levels (0.6 and 60 milliwatts per kilogram). When they examined the rats' brains afterward, they found no signs of damage including blood-brain barrier leakage, cell death, or aging-related changes. This contradicts some earlier studies from the same research group that found brain effects at similar exposure levels.
Nittby H et al. · 2008
Swedish researchers exposed rats to cell phone radiation (GSM-900) for 2 hours weekly over more than a year, using power levels similar to what your phone emits. The exposed rats showed significantly impaired memory, specifically struggling to remember objects and when they encountered them compared to unexposed control rats. This suggests that chronic low-level cell phone radiation exposure may affect cognitive function and memory formation.
Grafström G et al. · 2008
Swedish researchers exposed rats to GSM-900 cell phone radiation once weekly for over a year at power levels similar to what humans experience during phone calls. When they examined the rats' brains afterward, they found no signs of damage including blood-brain barrier leakage, cell death, or aging-related changes. This suggests that intermittent cell phone radiation exposure at typical usage levels may not cause detectable brain tissue damage.
Nittby H et al. · 2008
Swedish researchers exposed rats to cell phone radiation for 55 weeks and found significant memory problems compared to unexposed rats. The exposed animals had trouble remembering objects and when they encountered them, suggesting chronic mobile phone radiation may impair specific memory functions.
Pakhomov AG, Gaj ek P, Allen L, Stuck BE, Murphy MR · 2002
Researchers exposed yeast cell cultures to extremely high-powered microwave pulses (250,000 watts peak power) and compared the effects to continuous wave exposure at the same frequency and average power. Despite peak power levels 200,000 times higher than average, both exposure types produced identical effects on cell growth that correlated only with heating. The study found no evidence that extremely high peak power creates unique biological effects beyond thermal heating.
Grémiaux A et al. · 2015
French researchers exposed rose bushes to 900MHz electromagnetic fields (the same frequency used by cell phones) and tracked their growth for over a month. They found that EMF exposure significantly reduced growth by 45% in newly developing shoots, but only when plants were exposed at their earliest development stage. The effect occurred at extremely low power levels, ruling out heating as the cause.
Kesari KK, Behari J. · 2010
Researchers exposed male rats to 50 GHz microwave radiation (similar to 5G frequencies) for 2 hours daily over 45 days and examined the effects on sperm cells. The exposed rats showed significant damage to sperm quality, including increased cell death, disrupted cell division cycles, and reduced antioxidant defenses that normally protect cells from damage. These changes suggest the radiation could contribute to male fertility problems.
Kesari KK, Behari J. · 2009
Researchers exposed rats to 50-gigahertz microwave radiation (similar to 5G frequencies) for 2 hours daily over 45 days at very low power levels. The study found significant DNA damage in brain cells, along with disrupted antioxidant defenses and decreased protein kinase C activity. These cellular changes suggest that even low-level millimeter wave exposure may affect brain function and cellular health.
Cetin H et al. · 2014
Researchers exposed pregnant rats and their offspring to mobile phone radiation (900 and 1800 MHz) for 60 minutes daily, then measured oxidative stress markers in the brain and liver. The study found that EMF exposure decreased protective antioxidants in the liver while increasing oxidative stress markers in the brain, particularly affecting selenium levels. This suggests that mobile phone radiation can overwhelm the body's natural antioxidant defenses during critical developmental periods.
Hung CS, Anderson C, Horne JA, McEvoy P · 2007
Researchers exposed 10 healthy young adults to different mobile phone signal modes for 30 minutes, then measured how long it took them to fall asleep. They found that exposure to 'talk mode' signals significantly delayed sleep onset compared to listening mode or no signal exposure. The study suggests that the specific signal patterns phones emit during calls may interfere with the brain's natural transition to sleep.
Hung CS, Anderson C, Horne JA, McEvoy P. · 2007
Researchers exposed sleep-deprived people to mobile phone signals for 30 minutes, then monitored their brain waves during sleep. Active phone transmissions during "talk mode" significantly delayed deep sleep onset compared to other phone modes, suggesting cell phone use can disrupt natural sleep patterns.
de Pomerai D et al. · 2000
Researchers exposed tiny nematode worms to extremely low-power 750-MHz microwaves overnight and found increased production of heat shock proteins - cellular stress indicators that normally appear when organisms are damaged by heat or toxins. The microwave exposure was 1,000 times below current safety limits, yet still triggered this biological stress response, suggesting the effect was not caused by heating but by the electromagnetic fields themselves.
Wolke S, Neibig U, Elsner R, Gollnick F, Meyer R, · 1996
German researchers exposed guinea pig heart cells to cell phone radiation frequencies (900-1,800 MHz) and measured calcium levels, which are crucial for heart function. They found essentially no significant effects on cellular calcium balance, suggesting low-level RF exposure may not disrupt basic heart cell signaling.
Tattersall JE et al. · 2001
Researchers exposed rat brain tissue to cell phone-frequency radiation at 700 MHz and found it altered brain cell electrical activity by up to 120%, even at extremely low power levels that caused no heating, suggesting the brain responds to radiofrequency fields through non-thermal biological mechanisms.
Qureshi MRA, Alfadhl Y, Chen X, Peyman A, Maslanyj M, Mann S · 2018
Researchers calculated how much radiofrequency energy from smart meters gets absorbed by human bodies. Children absorbed the most energy, especially when within 15 centimeters of 2.4 GHz meters. Though levels stayed below safety limits, the study confirms smart meters cause measurable energy absorption in tissue.
S. Kwee, P. Raskmark & S. Velizarov · 2001
Danish researchers exposed human cells to weak 960 MHz microwave radiation (similar to cell phones) at extremely low power levels for 20 minutes. They found that cells produced significantly more heat-shock proteins (Hsp-70), which are cellular stress markers, even though the radiation was too weak to cause any heating. This suggests that cells can detect and respond to radiofrequency radiation through non-thermal biological mechanisms.