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

Local exposure of 849 MHz and 1763 MHz radiofrequency radiation to mouse heads does not induce cell death or cell proliferation in brain

Kim TH et al. · 2008

Researchers exposed mice to cell phone radiation at 849 MHz and 1763 MHz frequencies for up to 12 months, delivering radiation directly to their heads at levels much higher than typical phone use. They found no evidence of brain cell death, abnormal cell growth, or other cellular changes in the exposed animals compared to unexposed controls.

Brain & Nervous SystemNo Effects Found

Effects of exposure to electromagnetic fields emitted by GSM 900 and WCDMA mobile phones on cognitive function in young male subjects

Sauter C et al. · 2011

German researchers exposed 30 young men to mobile phone radiation (900 MHz and 1,966 MHz) for over 7 hours daily for three days, then tested their cognitive abilities including attention, memory, and vigilance. After accounting for natural daily variations in mental performance, they found no significant effects from either type of phone radiation on any cognitive function tested.

Changes in serum alkaline phosphatase activity during in vitro exposure to amplitude-modulated electromagnetic field of ultrahigh frequency (2375 MHz) in guinea pigs

Pashovkina MS, Akoev IG · 2000

Russian researchers exposed guinea pig blood samples to 2375 MHz microwave radiation (similar to WiFi frequencies) for just 1-3 minutes and measured changes in alkaline phosphatase, an important enzyme involved in cellular metabolism. They found that specific pulse frequencies, particularly at 70 Hz, nearly doubled the enzyme's activity levels. This suggests that even brief exposures to common wireless frequencies can trigger measurable biological responses at the cellular level.

CardiovascularNo Effects Found

Microwave influence on the isolated heart function: II. Combined effect of radiation and some drugs.

Pakhomov AG, Dubovick BV, Degtyariov IG, Pronkevich AN · 1995

Russian researchers exposed isolated frog heart tissue to 915 MHz microwave radiation (similar to cell phone frequencies) for 40 minutes to see how it affected heart function, both alone and combined with various drugs. They found that microwaves alone had no effect on heart rhythm or strength, but when combined with caffeine, the microwaves amplified caffeine's stimulating effects by about 15% - even at power levels too low to cause heating. This suggests that non-thermal microwave exposure might interact with certain substances to affect heart function in ways we don't fully understand.

Thermal tolerance reduces hyperthermia-induced disruption of working memory: a role for endogenous opiates?

Mickley GA, Cobb BL · 1998

Researchers exposed rats to microwave radiation at levels that caused significant body heating and found it disrupted their ability to distinguish between familiar and new objects - a key indicator of working memory function. However, rats that had been previously exposed to the heating developed a tolerance that protected them from both the temperature increase and memory problems. The study suggests that microwave-induced heating can impair cognitive function, but the brain may adapt to protect itself from repeated exposures.

Spatial memory recovery in Alzheimer's rat model by electromagnetic field exposure.

Akbarnejad Z et al. · 2017

Researchers exposed rats with Alzheimer's-like brain damage to 50 Hz electromagnetic fields (the same frequency as power lines) for 14 days and tested their memory using a water maze. The electromagnetic field exposure significantly improved the rats' learning and memory abilities, even reversing some of the cognitive damage. This suggests that certain electromagnetic frequencies might have therapeutic potential for neurodegenerative conditions.

Immune SystemNo Effects Found

Molecular responses of Jurkat T-cells to 1763 MHz radiofrequency radiation.

Huang TQ, Lee MS, Oh E, Zhang BT, Seo JS, Park WY. · 2008

Researchers exposed immune system T-cells to cell phone radiation at 1763 MHz for 24 hours to see if it caused cellular damage or changes in gene activity. They found no significant effects on cell growth, DNA damage, or major gene expression changes, though two immune-related genes showed minor decreases. This suggests that 24-hour exposure to this specific frequency at high power levels did not cause detectable harm to these immune cells.

Behavioral teratologic studies using microwave radiation: is there an increased risk from exposure to cellular phones and microwave ovens?

Jensh RP · 1997

Pregnant rats exposed to microwave radiation at cell phone and microwave oven frequencies showed concerning effects in offspring. The highest frequency (6000 MHz) caused delayed development, reduced birth weight, and altered brain function, suggesting certain microwave frequencies may affect developing brains.

Effects of 2.45-GHz microwave radiation and phorbol ester 12-O-tetradecanoylphorbol-13-acetate on dimethylhydrazine-induced colon cancer in mice.

Wu RY, Chiang H, Shao BJ, Li NG, Fu YD · 1994

Researchers exposed mice to 2.45 GHz microwave radiation (the same frequency used in WiFi and microwave ovens) for 3 hours daily over 5 months to see if it would accelerate colon cancer development. The mice were also given a known cancer-causing chemical. The microwave radiation did not increase cancer rates or make tumors worse compared to the chemical alone.

Local exposure of the rat cortex to radiofrequency electromagnetic fields increases local cerebral blood flow along with temperature

Masuda H et al. · 2011

Researchers exposed rat brains to cell phone-frequency radiation and found it increased both brain temperature and blood flow. Higher radiation levels caused greater effects. This shows radiofrequency radiation triggers measurable biological changes in brain tissue, including the brain's natural response to heating.

Local exposure of the rat cortex to radiofrequency electromagnetic fields increases local cerebral blood flow along with temperature.

Masuda H et al. · 2011

Japanese researchers exposed rat brain tissue to 2-GHz radiofrequency radiation at various intensities and measured changes in blood flow and temperature. They found that RF exposure significantly increased both local brain blood flow and temperature in a dose-dependent manner - the higher the exposure, the greater the response. This demonstrates that RF radiation directly affects brain physiology by triggering the body's natural response to increased heat in brain tissue.

DNA & Genetic DamageNo Effects Found

Micronuclei in the peripheral blood and bone marrow cells of rats exposed to 2450 MHz radiofrequency radiation.

Vijayalaxmi et al. · 2001

Researchers exposed rats to 2450 MHz radiofrequency radiation (the same frequency used in microwave ovens and Wi-Fi) for 24 hours at high intensity levels to see if it would damage their DNA. They looked for micronuclei (tiny fragments that indicate genetic damage) in blood and bone marrow cells. The study found no significant DNA damage compared to unexposed rats, even at radiation levels much higher than typical human exposure.

CardiovascularNo Effects Found

Cardiovascular and thermal effects of microwave irradiation at 1 and/or 10 GHz in anesthetized rats.

Jauchem JR, Ryan KL, Freidagger MR · 2000

Researchers exposed anesthetized rats to microwave radiation at 1 GHz, 10 GHz, or both frequencies combined at high power levels (12 W/kg) until the animals died from overheating. They found that rats exposed to 1 GHz died fastest, while those exposed to 10 GHz survived longest, with combined exposure falling in between. This study was designed to understand how different microwave frequencies affect heat distribution in the body and cardiovascular responses during extreme thermal stress.

Cellular EffectsNo Effects Found

Effects of microwaves on membranes of hematopoietic cells in their structural and functional organization.

Rotkovska D, Bartonickova A, Kautska J · 1993

Researchers exposed mouse bone marrow cells to microwave radiation at 2.45 GHz (the same frequency used by microwave ovens and WiFi) to study effects on cell membranes and blood cell production. They found no structural damage to cell membranes and no changes in the cells' ability to produce blood cells in the spleen. However, they discovered that microwave exposure could potentially interfere with cell growth processes through receptor-level mechanisms.

Effects of continuous and pulsed 2450-MHz radiation on spontaneous lymphoblastoid transformation of human lymphocytes in vitro.

Czerska EM, Elson EC, Davis CC, Swicord ML, Czerski P · 1992

Researchers exposed human immune cells (lymphocytes) to microwave radiation at 2.45 GHz for five days, comparing continuous waves versus pulsed waves at the same power levels. They found that pulsed microwave radiation enhanced cellular transformation even when temperatures stayed normal, while continuous waves only caused effects when heating occurred. This suggests that the timing pattern of radiation exposure, not just the total energy, affects how our immune cells respond.

DNA & Genetic DamageNo Effects Found

Proliferation and cytogenetic studies in human blood lymphocytes exposed in vitro to 2450 MHz radiofrequency radiation.

Vijayalaxmi, Mohan, N, Meltz, ML, Wittler, MA, · 1997

Researchers exposed human blood cells to microwave radiation at 2450 MHz (the same frequency used in microwave ovens and WiFi) for 90 minutes to see if it would damage DNA or affect cell growth. They found no genetic damage, chromosome breaks, or changes in how fast the cells multiplied compared to unexposed cells. This suggests that short-term exposure to this type of radiation at these power levels may not immediately harm human blood cells.

Brain & Nervous SystemNo Effects Found

Characterization of biological effect of 1763 MHz radiofrequency exposure on auditory hair cells.

Huang TQ et al. · 2008

Researchers exposed mouse auditory hair cells (the cells responsible for hearing) to cell phone radiation at 1763 MHz for up to 48 hours at extremely high power levels - 10 times stronger than typical phone use. They found no DNA damage, no changes in cell cycles, no stress responses, and only 29 out of 32,000 genes showed any change. The study suggests that even at these high exposure levels, cell phone radiation doesn't cause measurable biological damage to the specialized cells in our ears.

Ouabain inhibition of kidney ATPase is altered by 9.14 GHz radiation.

Brown HD, Chattopadhyay SK · 1991

Researchers exposed dog kidney tissue to 9.14 GHz microwave radiation (similar to some radar frequencies) for 5 minutes and found it significantly disrupted how a key enzyme called ATPase functions. The radiation interfered with ouabain, a compound that normally regulates this enzyme, reducing its effectiveness as a control mechanism. This suggests microwave radiation can alter fundamental cellular processes that keep our kidneys working properly.

Neuroprotective effects of dietary supplement Kang-fu-ling against high-power microwave through antioxidant action

Hu S et al. · 2014

Researchers exposed rats to high-power microwave radiation for 15 minutes and found it caused memory problems and brain damage. However, when rats were given a dietary supplement called Kang-fu-ling for two weeks, it protected their brains from this microwave-induced damage by reducing harmful oxidative stress (cellular damage from free radicals). This suggests certain antioxidant compounds might help protect the brain from microwave radiation effects.

Naltrexone-sensitive analgesia following exposure of mice to 2450-MHz radiofrequency radiation

Maillefer RH, Quock RM · 1992

Researchers exposed mice to microwave radiation at 2450 MHz (the same frequency used in microwave ovens) for 10 minutes and measured their pain response. They found that higher radiation levels caused the mice's bodies to heat up and triggered natural pain-killing mechanisms in the brain, similar to how the body responds to other forms of thermal stress. This suggests that microwave radiation can cause biological effects beyond just heating tissue.

Japanese encephalitis virus (JEV): potentiation of lethality in mice by microwave radiation.

Lange DG, Sedmak J · 1991

Researchers exposed mice infected with Japanese encephalitis virus to microwave radiation at 2.45 GHz (the same frequency used in microwave ovens and WiFi). They found that microwave exposure made the viral infection significantly more deadly in a dose-dependent manner. The microwaves appeared to increase the permeability of blood vessels in the brain, allowing more virus to enter the central nervous system where it causes fatal damage.

Stress proteins are not induced in mammalian cells exposed to radiofrequency or microwave radiation.

Cleary, SF, Cao, G, Liu, LM, Egle, PM, Shelton, KR · 1997

Researchers exposed human and hamster cells to radiofrequency radiation at levels 25 to 100 times higher than typical phone use for 2 hours, then looked for signs of cellular stress. They found no evidence that RF radiation triggered the production of stress proteins - molecules cells make when damaged or threatened. This suggests that at these exposure levels, the radiation didn't cause detectable cellular stress responses.

Effect of isothermal radiofrequency radiation on cytolytic T lymphocytes.

Cleary, SF, Du, Z, Cao, G, Liu, LM, McCrady, C · 1996

Researchers exposed immune cells called T lymphocytes to 2.45 GHz radiofrequency radiation (the same frequency used in microwave ovens and WiFi) for 24 hours. They found that high-intensity RF exposure significantly reduced the cells' ability to multiply and function properly, while lower intensities caused initial stimulation followed by suppression. The effects were not simply due to heating, suggesting RF radiation directly interferes with immune cell function.