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
Sokolovic D et al. · 2008
Researchers exposed rats to cell phone radiation for 60 days and found it damaged brain cells through oxidative stress (harmful free radicals). Melatonin, a natural hormone, partially protected against this brain damage, suggesting phone radiation may harm brain tissue but antioxidants could help.
Chauhan P, Verma HN, Sisodia R, Kesari KK. · 2017
Researchers exposed 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. The exposed rats showed significant tissue damage and oxidative stress in their brain, liver, kidney, testis, and spleen compared to unexposed control rats. This suggests that even low-level microwave radiation exposure over time may cause cellular damage throughout the body.
Meena R, Kumari K, Kumar J, Rajamani P, Verma HN, Kesari KK · 2014
Researchers exposed male rats to WiFi-frequency radiation (2.45 GHz) for 2 hours daily over 45 days, finding significant damage to sperm production and testosterone levels. Melatonin supplements prevented most reproductive harm, suggesting microwave radiation threatens male fertility but antioxidants may offer protection.
Meena R, Kumari K, Kumar J, Rajamani P, Verma HN, Kesari KK. · 2014
Researchers exposed male rats to Wi-Fi frequency radiation (2.45 GHz) for 2 hours daily over 45 days, finding it damaged sperm DNA and caused oxidative stress in testicular tissue. The antioxidant melatonin prevented this damage, suggesting everyday microwave radiation may harm male fertility but antioxidants could provide protection.
Kesari KK, Kumar S, Behari J. · 2012
Researchers exposed young rats to 2.45 GHz microwave radiation (the same frequency used in WiFi and microwaves) for 2 hours daily over 45 days at power levels similar to many consumer devices. The exposed rats showed decreased melatonin production and increased markers of brain cell damage and death. This suggests that chronic exposure to common microwave frequencies may harm brain tissue and disrupt sleep-regulating hormones.
de Gannes FP et al. · 2009
French researchers exposed rats' heads to cell phone radiation (900 MHz GSM) for 2 hours to test whether it damages the blood-brain barrier (the protective layer around the brain) or kills brain cells. They found no evidence of brain damage or barrier leakage at exposure levels both below and above typical cell phone use. This study contradicted earlier research that had suggested cell phone radiation could harm the brain's protective barrier.
Dasdag et al. · 1999
Researchers exposed male rats to cell phone radiation for 2 hours daily over one month and examined their reproductive organs. They found that phones actively making calls (not just on standby) caused structural changes in the testes, specifically shrinking the seminiferous tubules where sperm are produced. The study also recorded higher body temperatures in rats exposed to active phone radiation.
Houston BJ, Nixon B, King BV, Aitken RJ, De Iuliis GN. · 2018
Researchers exposed mouse sperm to cell phone radiation (1.8 GHz) for 3-4 hours at low power. The radiation damaged sperm DNA, reduced sperm movement, and created harmful molecules in cell energy centers. This provides biological evidence for how wireless signals might affect male fertility.
Manta AK et al. · 2017
Researchers exposed fruit flies to mobile phone radiation for just 30 minutes and found it triggered a cascade of harmful cellular changes in their ovaries. The exposure increased damaging molecules called reactive oxygen species by 60%, altered the activity of 168 genes, and doubled the rate of cell death within hours. This demonstrates that brief mobile phone exposure can disrupt fundamental biological processes at the cellular level.
Manta AK et al. · 2017
Researchers exposed fruit flies to mobile phone radiation for 30 minutes. The radiation increased harmful molecules by 60%, altered 168 genes within 2 hours, and triggered cell death in reproductive organs within 4 hours, showing cellular damage from brief phone exposure.
Manta AK et al. · 2017
Researchers exposed fruit flies to mobile phone radiation for just 30 minutes and found significant biological disruptions in their ovaries. The exposure caused a 60% increase in harmful molecules called reactive oxygen species, altered the activity of 168 genes, and doubled the rate of cell death in reproductive tissue. These findings suggest that even brief exposure to cell phone radiation can trigger cellular stress and damage reproductive cells.
Zeni O et al. · 2012
Researchers exposed human immune cells (lymphocytes) to 3G cell phone radiation at various power levels for 20 hours, then treated them with a DNA-damaging chemical. They discovered that cells pre-exposed to radiation at 0.3 watts per kilogram showed less genetic damage than unexposed cells, suggesting the radiation triggered protective mechanisms. This adaptive response indicates that low-level radiofrequency exposure may prime cells to better defend against subsequent toxic challenges.
Chou CK, Guy AW, Kunz LL, Johnson RB, Crowley JJ, Krupp JH · 1992
Researchers exposed 200 rats to low-level microwave radiation (similar to cell phone frequencies) for nearly their entire lifetimes, 21.5 hours daily for 25 months. The study monitored blood chemistry, hormone levels, immune function, and overall health throughout the animals' lives. This represents one of the most comprehensive long-term studies of microwave radiation effects on living organisms.
Dasdag S; Akdag MZ; Ayy ld z O et al. · 2000
Researchers exposed pregnant rats to cell phone radiation at levels similar to human exposure (0.155 W/kg SAR) and found that while blood parameters remained normal, offspring were born with significantly lower birth weights. The effect disappeared in the next generation, suggesting the impact was limited to direct exposure during pregnancy.
Grigoriev YG et al. · 2010
Russian researchers exposed rats to microwave radiation at levels similar to what cell phones emit (2450 MHz frequency) for 7 hours daily over 30 days. They found the radiation triggered immune system changes in brain tissue, causing the body to produce antibodies against its own brain cells. This suggests that even low-level microwave exposure may cause autoimmune reactions where the immune system mistakenly attacks healthy tissue.
de Gannes FP et al. · 2009
French researchers exposed pregnant rats to 2450 MHz microwave radiation (the same frequency used in microwave ovens and WiFi) for 7 hours daily over 30 days to test whether this exposure affects immune function or causes birth defects. They found no effects on immune system markers or fetal development at the power levels tested. This study was designed to confirm earlier Russian and Ukrainian research that had suggested potential harmful effects.
Anderson LE et al. · 2004
Researchers exposed pregnant rats and their offspring to 1.6 GHz radiofrequency radiation (similar to cell phone signals) for two years to study cancer risk. They found no increased cancer rates or significant health differences between exposed and unexposed animals. This study suggests that long-term exposure to this type of RF radiation at the tested levels may not substantially increase cancer risk in rats.
Stagg RB et al. · 2001
Researchers exposed rats to cell phone radiation at levels up to 5 W/kg (similar to older phones held directly against the head) while measuring stress hormones and brain activity markers. The study found no differences in stress responses between animals exposed to the radiation versus those that were only restrained, suggesting the radiation itself didn't cause additional stress at these exposure levels.
Urban, P, Lukas, E, Roth, Z · 1998
Researchers exposed 20 healthy volunteers to electromagnetic fields from a Motorola mobile phone for 5 minutes and measured visual evoked potentials (electrical brain responses to visual stimuli) to see if phone radiation affected brain function. They found no changes in brain activity after the exposure. This small pilot study suggests short-term mobile phone use may not immediately disrupt this particular aspect of brain function.
Kumar A, Singh HP, Batish DR, Kaur S, Kohli RK. · 2015
Researchers exposed corn seedlings to cell phone radiation (1800 MHz) for different time periods and found that 4 hours of exposure significantly stunted growth and disrupted the plants' sugar metabolism. The radiation caused a 23% reduction in shoot growth and altered key enzymes responsible for breaking down starches and sugars that plants need for energy. This demonstrates that radiofrequency radiation can interfere with fundamental biological processes even in plants.
Fragopoulou AF et al. · 2012
Greek researchers exposed mice to cell phone and cordless phone radiation for 8 months and found that both sources significantly altered the expression of 143 brain proteins. The changes affected proteins involved in brain function, stress response, and cell structure across three different brain regions. These protein changes may explain common symptoms like headaches, sleep problems, and memory issues that people report with long-term wireless device use.
Fragopoulou AF et al. · 2012
Researchers exposed mice to mobile phone and cordless phone radiation for 8 months and examined brain tissue for protein changes. They found that both radiation sources significantly altered 143 different proteins in brain regions, including proteins involved in brain function, stress response, and cell structure. These protein changes may explain symptoms like headaches, memory problems, and sleep disturbances reported by people with long-term phone use.
Dasdag S, Akdag MZ, Kizil G, Kizil M, Cakir DU, Yokus B · 2012
Researchers exposed rats to cell phone radiation (900 MHz) for 2 hours daily over 10 months and examined their brains for signs of damage. They found significantly increased protein carbonyl levels, which indicates protein damage from oxidative stress. This suggests that long-term cell phone radiation exposure may harm brain proteins, potentially contributing to neurodegenerative processes.
Dasdag S, Akdag MZ, Ulukaya E, Uzunlar AK, Ocak AR · 2009
Researchers exposed rats to 900 MHz cell phone radiation for 2 hours daily over 10 months to study brain cell death (apoptosis) and oxidative stress. Surprisingly, they found reduced cell death and increased antioxidant activity in exposed rats compared to controls. This unexpected finding suggests the brain may activate protective mechanisms in response to chronic low-level radiation exposure.
Sharma A, Sisodia R, Bhatnagar D, Saxena VK. · 2014
Researchers exposed mice to 10 GHz microwave radiation for two hours daily over 30 days, then tested their memory using a water maze. Exposed mice took significantly longer to learn and remember locations, suggesting microwave exposure may impair memory formation and learning ability.