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

Amino acid concentrations in hypothalamic and caudate nuclei during microwave-induced thermal stress: analysis by microdialysis.

Mason PA et al. · 1997

Researchers exposed rats to high-power 5.02 GHz microwave radiation, heating their brains to dangerous temperatures. This thermal stress significantly increased three amino acid concentrations in critical brain regions including the hypothalamus. The findings suggest microwave heating disrupts normal brain chemistry beyond temperature-control areas.

Brain & Nervous SystemNo Effects Found

Using the nonlinear control of anesthesia-induced hypersensitivity of EEG at burst suppression level to test the effects of radiofrequency radiation on brain function.

Lipping T et al. · 2009

Researchers exposed eleven anesthetized pigs to mobile phone radiation at 890 MHz to test whether radiofrequency signals could trigger brain activity changes in a highly sensitive state. They found no correlation between RF exposure and brain wave patterns, though the animals experienced significant temperature increases (1.6°C) and elevated heart rates during the 10-minute exposures. This suggests that while RF radiation can cause heating effects, it may not directly stimulate brain activity even under conditions of heightened neural sensitivity.

Brain & Nervous SystemNo Effects Found

Using the nonlinear control of anaesthesia-induced hypersensitivity of EEG at burst suppression level to test the effects of radiofrequency radiation on brain function.

Lipping T et al. · 2009

Researchers exposed anesthetized pigs to GSM mobile phone radiation (890 MHz) to test whether radio frequency signals could trigger brain activity changes detectable in EEG measurements. The study used a highly sensitive testing method where anesthetized animals show exaggerated responses to even minor stimuli. Despite exposure levels of 31 W/kg (much higher than typical phone use), no changes in brain electrical activity were observed, though the animals did experience increased body temperature and heart rate.

DNA & Genetic DamageNo Effects Found

Absence of a synergistic effect between moderate-power radio-frequency electromagnetic radiation and adriamycin on cell-cycle progression and sister-chromatid exchange.

Ciaravino V, Meltz ML, Erwin DN · 1991

Researchers exposed Chinese hamster ovary cells to both microwave radiation (2.45 GHz) and adriamycin, a cancer drug that damages DNA, to see if the radiation would amplify the drug's harmful effects. After two hours of simultaneous exposure at 33.8 W/kg (a relatively high power level), they found no synergistic effect - the radiation didn't make the drug more damaging to cells or increase DNA damage. This suggests that microwave radiation at this level doesn't interact with certain toxic chemicals to create additional cellular harm.

DNA & Genetic DamageNo Effects Found

Influence of radiofrequency radiation on chromosome aberrations in CHO cells and its interaction with DNA-damaging agents.

Kerbacher JJ, Meltz ML, Erwin DN, · 1990

Researchers exposed Chinese hamster cells to high-intensity microwave radiation (2450 MHz) at levels far exceeding safety guidelines to see if it would damage chromosomes or make cancer drugs more harmful. Even at these extreme exposure levels-which heated the cells by over 3 degrees-the radiation caused no chromosome damage by itself and didn't increase the genetic damage from chemotherapy drugs. This suggests that radiofrequency radiation at this frequency doesn't directly break DNA or interfere with cellular repair mechanisms.

DNA & Genetic DamageNo Effects Found

Proflavin and microwave radiation: absence of a mutagenic interaction.

Meltz ML, Eagan P, Erwin DN · 1990

Researchers exposed mouse leukemic cells to 2.45-GHz microwave radiation (the same frequency as microwave ovens) at high power levels while simultaneously treating them with proflavin, a DNA-damaging drug. They found no evidence that the microwave radiation enhanced the drug's ability to cause genetic mutations, nor did the radiation alone cause any DNA damage. This suggests that microwave radiation at these levels does not interact with chemical mutagens to worsen genetic damage.

In vitro lymphocyte proliferation induced by radio-frequency electromagnetic radiation under isothermal conditions.

Cleary SF, Liu LM, Merchant RE · 1990

Researchers exposed human immune cells (lymphocytes) to radio frequency radiation at two common frequencies for 2 hours while carefully controlling temperature. They found that lower radiation levels actually stimulated immune cell activity, while higher levels suppressed it. This demonstrates that RF radiation can directly affect immune system function without any heating effects.

Non-thermal effects of electromagnetic fields at mobile phone frequency on the refolding of an intracellular protein: myoglobin.

Mancinelli F et al. · 2004

Italian researchers exposed myoglobin protein (found in muscle cells) to mobile phone frequency radiation for 3 hours and found it disrupted how the protein folded back into its proper shape. The electromagnetic fields slowed down the protein's natural folding process and altered its structural flexibility. This matters because proteins must fold correctly to function properly, and misfolded proteins are linked to various diseases.

Differential response of the permeability of the rat liver canalicular membrane to sucrose and mannitol following in vivo acute single and multiple exposures to microwave radiation (2.45 GHz) and radiant-energy thermal stress.

Lange DG, D'Antuono ME, Timm RR, Ishii TK, Fujimoto JM. · 1993

Researchers exposed rats to microwave radiation at 2.45 GHz (the same frequency used by microwave ovens and WiFi) to study effects on liver function. They found that repeated exposures caused permanent changes to liver cell membranes that control bile production and toxin processing. The microwave radiation caused more severe liver damage than heat alone, suggesting the electromagnetic fields themselves were harmful beyond just thermal heating effects.

The effect of pulsed microwaves on passive electrical properties and interspike intervals of snail neurons.

Field AS, Ginsburg K, Lin JC · 1993

Researchers exposed snail neurons to pulsed 2.45 GHz microwaves and found they caused significant changes to the neurons' electrical properties, specifically increasing their resistance to electrical current. These effects occurred without any temperature changes, proving the microwaves directly affected nerve cell function. This demonstrates that radiofrequency radiation can alter how neurons work at the cellular level.

Oxidative StressNo Effects Found

Effect of millimeter wave radiation on catalase activity.

Logani MK, Agelan A, Ziskin MC. · 2002

Researchers exposed mice to high-intensity millimeter wave radiation at 42.2 GHz to test whether it could protect an enzyme called catalase from damage caused by chemotherapy drugs. The radiation, delivered at power levels about 1,000 times higher than typical cell phone exposure, showed no protective effect on the enzyme. This suggests that millimeter waves at these frequencies don't provide the cellular protection some researchers had hoped to find.

CardiovascularNo Effects Found

Microwave influence on the isolated heart function: I. Effect of modulation.

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

Russian researchers exposed isolated frog heart tissue to microwave radiation at frequencies used by cell phones (915 and 885 MHz) to see if different pulse patterns affected heart function. They tested 400 different exposure combinations and found that heart changes only occurred when the microwaves generated enough heat to raise tissue temperature by 0.1-0.4 degrees Celsius. The heart effects were identical to those produced by conventional heating, suggesting the microwaves worked purely through thermal heating rather than any unique electromagnetic mechanism.

Influence of anesthesia on ocular effects and temperature in rabbit eyes exposed to microwaves.

Kojima M et al. · 2004

Researchers exposed rabbit eyes to high-intensity microwave radiation at 2.45 GHz to study how anesthesia affects heat buildup and eye damage. They found that anesthetized rabbits experienced much more severe eye damage and 2-9°C higher eye temperatures than conscious rabbits, even though all received identical radiation exposure. This reveals that the body's natural cooling responses help protect against microwave-induced heating and tissue damage.

Microwave exposure alters the expression of 2-5A-dependent RNase.

Krause D, Mullins JM, Penafiel LM, Meister R, Nardone RM, · 1991

Researchers exposed mouse cells to 2.45 GHz microwave radiation (the same frequency used in microwave ovens) at levels 20 times higher than safety limits for 4 hours. The radiation significantly increased the activity of RNase L, an enzyme involved in the body's antiviral defense system. This suggests that microwave radiation can trigger cellular stress responses even when cells appear healthy and continue growing normally.

Electromagnetic millimeter waves increase the duration of anaesthesia caused by ketamine and chloral hydrate in mice.

Rojavin MA, Ziskin MC · 1997

Researchers exposed anesthetized mice to millimeter wave radiation at 61.22 GHz and found it extended the duration of anesthesia by approximately 50%. The effect was blocked when mice were pretreated with naloxone (an opioid blocker), suggesting the radiation triggers the release of the body's natural opioids. This demonstrates that millimeter wave exposure can directly alter brain chemistry and nervous system function.

DNA & Genetic DamageNo Effects Found

DNA damage in frog erythrocytes after in vitro exposure to a high peak-power pulsed electromagnetic field.

Chemeris NK et al. · 2004

Researchers exposed frog blood cells to extremely high-power pulsed electromagnetic fields (8.8 GHz) to test whether the radiation could damage DNA. While they did observe DNA damage, they found it was caused entirely by the 3.5°C temperature increase from the intense exposure, not by any non-thermal effects of the radiation itself. When they heated cells to the same temperature without radiation, the DNA damage was identical.

CardiovascularNo Effects Found

Comparative effects of extremely high power microwave pulses and a brief CW irradiation on pacemaker function in isolated frog heart slices.

Pakhomov AG et al. · 2000

Researchers exposed isolated frog heart tissue to extremely high-power microwave pulses (up to 350 million watts per kilogram) and compared the effects to lower-power continuous microwave exposure. Both exposure types caused the same temporary changes in heart rhythm that were directly proportional to heating, with no additional effects from the ultra-high power pulses. This suggests that microwave effects on heart function are purely thermal (heat-related) rather than caused by the electromagnetic fields themselves.

Brain & Nervous SystemNo Effects Found

Modification of acoustic startle by microwave pulses in the rat: a preliminary report.

Seaman RL, Beblo DA · 1992

Researchers exposed rats to intense microwave pulses just before loud sounds to see if the microwaves affected their startle reflex. They found that moderate-intensity microwave pulses delayed and reduced the rats' startle responses, but surprisingly, higher-intensity pulses had no effect. This suggests that microwave radiation can interfere with nervous system responses, but the relationship isn't straightforward.