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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

Mobile phones exposure induces changes of contingent negative variation in humans

de Tommaso M et al. · 2009

Italian researchers exposed 10 volunteers to cell phone radiation at 900 MHz and measured their brain's electrical activity using EEG. They found that both active phones and phones with blocked radiation (but still powered on) reduced brain arousal and expectation responses compared to phones that were completely off. This suggests that cell phone exposure affects how the brain processes and anticipates information.

DNA & Genetic DamageNo Effects Found

Effects of modulated microwave radiation at cellular telephone frequency (1.95 GHz) on X-ray-induced chromosome aberrations in human lymphocytes in vitro.

Manti L et al. · 2008

Italian researchers exposed human blood cells to cell phone radiation (1.95 GHz UMTS signal) for 24 hours, then hit them with X-rays to see if the RF exposure made the radiation damage worse. While the cell phone signals didn't increase the number of damaged cells, they did cause a small but measurable increase in the severity of chromosome damage within each affected cell at the higher exposure level (2.0 W/kg SAR). This suggests RF radiation might interfere with the cell's ability to repair DNA damage from other sources.

Brain & Nervous SystemNo Effects Found

Psychomotor performance is not influenced by brief repeated exposures to mobile phones

Curcio G et al. · 2008

Italian researchers exposed 24 people to GSM mobile phone radiation (902.40 MHz) for three separate 15-minute sessions and tested their reaction times and finger coordination after each exposure. They found no measurable effects on psychomotor performance, though there was a slight non-significant trend toward faster reaction times. The study suggests that brief, repeated mobile phone exposures at typical power levels don't impair basic motor skills and reflexes.

Effects of modulated microwave radiation at cellular telephone frequency (1.95 GHz) on X-ray-induced chromosome aberrations in human lymphocytes in vitro.

Manti L et al. · 2008

Researchers exposed human blood cells to cell phone radiation, then X-rays, to test DNA damage effects. While radiation didn't increase damaged cells overall, it increased chromosome damage within affected cells by a small but significant amount, suggesting interference with DNA repair processes.

Nonthermal effects of radiofrequency-field exposure on calcium dynamics in stem cell-derived neuronal cells: elucidation of calcium pathways.

Rao VS et al. · 2008

Mouse brain cells exposed to cell phone-like radiofrequency radiation showed dramatically altered calcium signaling, with three times more calcium spikes than unexposed cells. This matters because calcium controls critical brain cell functions including growth, development, and communication between neurons.

Psychomotor performance is not influenced by brief repeated exposures to mobile phones.

Curcio G et al. · 2008

Researchers exposed 24 people to cell phone radiation (902.40 MHz at 0.5 W/kg SAR) for three 15-minute sessions and tested their reaction times and finger coordination after each exposure. They found no statistically significant effects on these motor skills, though there was a slight trend toward faster reaction times. The study suggests that brief, repeated cell phone exposures don't appear to impair basic motor performance.

Cancer & TumorsNo Effects Found

Carcinogenicity Study of 217 Hz Pulsed 900 MHz electromagnetic fields in pim1 transgenic mice.

Oberto G et al. · 2007

Researchers exposed genetically modified mice to pulsed 900 MHz radiofrequency radiation (similar to cell phone signals) for 18 months to test whether it could cause cancer. Despite using exposure levels up to three times higher than a previous study that found increased lymphomas, this larger study found no increase in tumors or cancer at any of the tested exposure levels. This contradicts earlier research suggesting cell phone radiation might promote cancer development.

Oxidative StressNo Effects Found

Free Radical Release and HSP70 Expression in Two Human Immune-Relevant Cell Lines after Exposure to 1800 MHz Radiofrequency Radiation.

Lantow M, Schuderer J, Hartwig C, Simko M. · 2006

Researchers exposed human immune cells to 1800 MHz radiofrequency radiation (the same frequency used by GSM cell phones) at various power levels to see if it would trigger free radical production or stress protein responses. They found no significant effects on either measure, even at exposure levels up to 2.0 W/kg. This suggests that RF radiation at these levels doesn't cause oxidative stress in these particular immune cell types.

Oxidative StressNo Effects Found

Free radical release and HSP70 expression in two human immune-relevant cell lines after exposure to 1800 MHz Radiofrequency Radiation.

Lantow M, Schuderer J, Hartwig C, Simko M. · 2006

Researchers exposed human immune cells to cell phone radiation at 1800 MHz (the frequency used by GSM networks) to see if it would trigger the production of harmful free radicals or stress proteins. Even at high exposure levels up to 2.0 W/kg, the radiation did not cause any significant increase in free radical production or stress protein expression in the cells. This suggests that cell phone radiation at these levels may not trigger the type of cellular damage that free radicals can cause.

Cancer & TumorsNo Effects Found

Effects of mobile phone radiation on UV-induced skin tumourigenesis in ornithine decarboxylase transgenic and non-transgenic mice.

Heikkinen P et al. · 2003

Finnish researchers exposed mice to mobile phone radiation for one year while also exposing them to UV light to see if the combination would increase skin cancer rates. The mobile phone radiation alone did not significantly increase tumor development, though there was a slight acceleration in tumor growth timing that the researchers noted deserves further investigation.

Subjective symptoms among mobile phone users--a consequence of absorption of radiofrequency fields?

Wilén J, Sandström M, Hansson Mild K · 2003

Researchers studied 2,402 mobile phone users to see if radiation absorption levels (SAR) correlated with symptoms like headaches and fatigue. They found that phones with SAR values above 0.5 watts per kilogram, especially when used for long calling times, were associated with increased symptom reporting. This suggests that the amount of radiation your phone emits into your head may directly influence how you feel after using it.

Cellular EffectsNo Effects Found

Influence of microwaves on different types of receptors and the role of peroxidation of lipids on receptor-protein shedding.

Philippova TM, Novoselov VI, Alekseev SI · 1994

Russian researchers exposed rat brain and liver cells to 900 MHz microwave radiation (similar to cell phones) for 15 minutes to see how it affected cellular receptors that help cells communicate. While some receptors showed no changes, liver cell receptors experienced a dramatic fivefold decrease in their ability to bind with important molecules. The researchers found this happened because the microwave exposure caused receptor proteins to break away from cell membranes, suggesting that even brief RF exposure can disrupt how cells function at the molecular level.

Brain & Nervous SystemNo Effects Found

Bursting responses of Lymnea neurons to microwave radiation.

Bolshakov MA, Alekseev SI · 1992

Researchers exposed pond snail neurons to 900 MHz microwave radiation to study effects on brain cell activity. They found that pulsed microwave signals at low power levels (0.5 W/kg SAR) caused sudden bursts of irregular firing in neurons, while continuous wave signals at the same power had no effect. This suggests that the pattern of microwave exposure, not just the power level, can alter how brain cells communicate.

The effects of whole body cell phone exposure on the t1 relaxation times and trace elements in the serum of rats.

Aksen F, Dasdag S, Akdag MZ, Askin M, Dasdag MM. · 2004

Researchers exposed rats to cell phone radiation for 20 minutes daily over a month to see if it affected essential minerals in their blood. They found that manganese and zinc levels changed significantly in exposed rats, while iron and copper remained normal. This suggests that cell phone radiation may disrupt how the body processes certain trace elements that are crucial for proper cellular function.

Reproductive HealthNo Effects Found197 citations

Whole body exposure of rats to microwaves emitted from a cell phone does not affect the testes.

Dasdag S et al. · 2003

Researchers exposed rats to cell phone radiation for 20 minutes daily over one month to examine effects on male fertility. They found no changes in sperm count, sperm quality, or testicular tissue structure compared to unexposed rats. The study suggests that short-term cell phone exposure at typical power levels may not immediately harm male reproductive health.

A method for safety testing of radiofrequency/microwave-emitting devices using MRI.

Alon L, Cho GY, Yang X, Sodickson DK, Deniz CM. · 2014

Researchers developed a new method using MRI to measure how much radiofrequency energy devices like cell phones deposit into body tissues by tracking temperature changes. When they tested a cell phone at maximum power for 15 minutes, it caused tissue heating of 1.7°C and delivered energy at 0.54 watts per kilogram. This technique provides a more accurate way to test whether wireless devices meet safety limits for human exposure.

Brain & Nervous SystemNo Effects Found

Cognitive effects of cellular phones: a possible role of non-radiofrequency radiation factors

Hareuveny R, Eliyahu I, Luria R, Meiran N, Margaliot M · 2011

Researchers tested whether cell phone radiation affects cognitive function by having 29 men perform memory tasks while phones were attached to their heads. In a clever twist, they used external antennas placed far away to drastically reduce the actual radiation exposure from the phones. Despite the minimal radiation, they still found the same cognitive effects as in their previous studies with normal phone exposure.

2100-MHz electromagnetic fields have different effects on visual evoked potentials and oxidant/antioxidant status depending on exposure duration.

Hidisoglu E et al. · 2016

Researchers exposed rats to 2100-MHz radiofrequency radiation (similar to 3G cell phone signals) for 2 hours daily, comparing short-term (1 week) versus long-term (10 weeks) exposure. They found that short-term exposure actually improved brain function and antioxidant defenses, while long-term exposure caused brain dysfunction and oxidative damage. This suggests that duration of EMF exposure matters significantly for health effects.

Effects of 1800-MHz radiofrequency fields on circadian rhythm of plasma melatonin and testosterone in male rats.

Qin F et al. · 2012

Researchers exposed male rats to cell phone frequency radiation (1800 MHz) for 2 hours daily over 32 days and measured how this affected their natural daily cycles of melatonin and testosterone production. The radiation disrupted both hormones' normal rhythms, with melatonin being more severely affected than testosterone. This suggests that radiofrequency exposure can interfere with the body's internal biological clock that regulates crucial hormones.

Cancer & TumorsNo Effects Found

Lack of promoting effects of the electromagnetic near-field used for cellular phones (929.2 MHz) on rat liver carcinogenesis in a medium-term liver bioassay.

Imaida K et al. · 1998

Japanese researchers exposed rats to 929.2 MHz cell phone radiation for 90 minutes daily over 6 weeks to test whether the radiation could promote liver cancer development. The study used relatively high SAR levels (up to 7.2 W/kg) and found no difference in pre-cancerous liver lesions between exposed and unexposed rats. This suggests that cell phone radiation at these levels does not accelerate liver cancer progression in this animal model.

Reproductive HealthNo Effects Found

Histological and Cytological Examination of Rat Reproductive Tissue After Short-Time Intermittent Radiofrequency Exposure / HISTOLOŠKA I CITOLOŠKA ISTRAŽIVANJA TKIVA REPRODUKTIVNOG SUSTAVA ŠTAKORA NAKON KRATKOTRAJNE ISPREKIDANE IZLOŽENOSTI RADIOFREKVENCIJSKOM ZRAČENJU.

Trošić I, Mataušić-Pišl M, Pavičić I, Marjanović AM. · 2013

Researchers exposed male rats to 915 MHz radiofrequency radiation (similar to cell phone frequencies) for one hour daily over two weeks to study effects on reproductive health. They found no significant changes in testicular structure, sperm count, sperm mobility, or sperm appearance compared to unexposed rats. The study suggests that short-term intermittent RF exposure at these levels may not pose immediate risks to male reproductive function.

Effect of electromagnetic radiofrequency radiation on the rats' brain, liver and kidney cells measured by comet assay.

Trosić I et al. · 2011

Researchers exposed rats to cell phone radiation at 915 MHz for one hour daily over two weeks and examined DNA damage in brain, liver, and kidney cells using a comet assay test. They found measurable DNA breaks in liver and kidney cells, with less pronounced effects in brain cells. This suggests that radiofrequency radiation at levels similar to cell phone emissions can cause genetic damage in multiple organs.