8,655 Studies Reviewed. 86.9% Found Biological Effects. The Evidence is Clear.
All Exposure Types

SAR (Specific Absorption Rate)

Share:

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 899 studies with measured sar (specific absorption rate) exposure

Cellular EffectsNo Effects Found

Effects of exposure to a 1950 MHz radio frequency field on expression of Hsp70 and Hsp27 in human glioma cells.

Miyakoshi J et al. · 2005

Researchers exposed human brain tumor cells to 1950 MHz radiofrequency radiation (similar to 3G cell phone frequencies) at various intensities for up to 2 hours. While the radiation didn't affect cell growth or activate major stress response proteins, it did reduce a specific cellular protection mechanism at the highest exposure level (10 W/kg). This suggests that even when cells appear unaffected, subtle molecular changes may still be occurring.

Exposure to pulse-modulated radio frequency electromagnetic fields affects regional cerebral blood flow.

Huber R et al. · 2005

Swiss researchers exposed 12 healthy men to cell phone-like radio frequency radiation for 30 minutes and used brain scans to measure blood flow changes. They found that exposure increased blood flow in the brain's frontal cortex, but only when the signal was pulse-modulated like actual cell phones (not steady signals like cell towers). This demonstrates that cell phone radiation can measurably alter brain activity within just 30 minutes of exposure.

Blood-forming system in rats after whole-body microwave exposure; reference to the lymphocytes.

Trosic I, Busljeta I, Pavicic I. · 2004

Croatian researchers exposed rats to 2.45 GHz microwave radiation (the same frequency used by WiFi and microwave ovens) for 2 hours daily over periods up to 30 days. They found that longer exposures significantly reduced lymphoblasts, which are immature immune cells that develop into infection-fighting lymphocytes. The researchers interpreted this as a stress response in the blood-forming system, suggesting the body was adapting to the microwave exposure.

Brain & Nervous SystemNo Effects Found

Effects of exposure of the ear to GSM microwaves: in vivo and in vitro experimental studies.

Aran JM et al. · 2004

French researchers exposed guinea pigs' ears to cell phone radiation (900 MHz GSM) for 1 hour daily over 2 months at power levels up to 4 times higher than typical phone use. They found no damage to hearing function or inner ear structures, even when examining the ears immediately after exposure and 2 months later. The study also tested isolated ear tissue from newborn rats and found no cellular damage under microscopic examination.

Brain & Nervous SystemNo Effects Found110 citations

Head-only exposure to GSM 900-MHz electromagnetic fields does not alter rat's memory in spatial and non-spatial tasks.

Dubreuil D, Jay T, Edeline JM. · 2003

Researchers exposed rats to 900 MHz cell phone radiation (GSM signals) for 45 minutes to test whether it affected their memory and learning abilities. The rats performed just as well as unexposed rats on complex maze tests and object recognition tasks, with one group even showing slightly better performance. This suggests that brief exposure to cell phone-level radiation doesn't impair memory function in rats.

Immune SystemNo Effects Found

Effects of In Vivo Exposure to GSM-Modulated 900 MHz Radiation on Mouse Peripheral Lymphocytes.

Gatta L et al. · 2003

Researchers exposed mice to cell phone radiation (900 MHz GSM) for 2 hours daily over 1-4 weeks to see if it would affect their immune system cells in the spleen. They found no significant changes in the numbers or types of immune cells, and the cells responded normally when stimulated. The study concluded that cell phone radiation at these levels is unlikely to cause clinically relevant immune system problems.

Genotoxicity of radiofrequency signals. I. Investigation of DNA damage and micronuclei induction in cultured human blood cells.

Tice RR, Hook GG, Donner M, McRee DI, Guy AW. · 2002

Researchers exposed human blood cells to cell phone radiation from different technologies (CDMA, TDMA, GSM) at various power levels for 3 or 24 hours. They found that 24-hour exposures at higher power levels (5-10 W/kg) caused a four-fold increase in chromosomal damage across all phone technologies tested. This suggests that prolonged exposure to cell phone radiation can damage the genetic material in human immune cells.

Brain & Nervous SystemNo Effects Found

Does head-only exposure to GSM-900 electromagnetic fields affect the performance of rats in spatial learning tasks?

Dubreuil D, Jay T, Edeline JM. · 2002

French researchers tested whether 45-minute exposures to 900-MHz GSM cell phone radiation affected spatial learning and memory in rats. They found no differences in performance on maze tasks between rats exposed to cell phone radiation (at levels of 1 and 3.5 W/kg SAR) and unexposed control rats. This contradicts some earlier studies that suggested electromagnetic fields could impair learning abilities.

Cancer & TumorsNo Effects Found

The Effects of 860 MHz Radiofrequency Radiation on the Induction or Promotion of Brain Tumors and Other Neoplasms in Rats.

Zook BC, Simmens SJ, · 2001

Researchers exposed rats to 860 MHz radiofrequency radiation for up to 22 months to see if it could cause or accelerate brain tumors. The study found no statistically significant increase in brain tumors or other cancers from the RF exposure, even when combined with a known cancer-causing chemical. This was a large, well-controlled study using 900 rats with extensive tissue analysis.

Cancer & Tumors119 citations

Spontaneous and nitrosourea-induced primary tumors of the central nervous system in Fischer 344 rats exposed to frequency-modulated microwave fields.

Adey WR et al. · 2000

Researchers exposed 540 laboratory rats to radiofrequency signals mimicking cell phone use throughout their entire lives to test whether this exposure increases brain tumor risk. The study found no increased rates of brain tumors from the RF exposure, even when combined with a cancer-causing chemical. Interestingly, this contrasts with the same research team's previous study using digital phone signals, which showed a protective effect against brain tumors.

Exposure to pulsed high-frequency electromagnetic field during waking affects human sleep EEG.

Huber R et al. · 2000

Swiss researchers exposed healthy young men to cell phone radiation (900 MHz) for 30 minutes before bedtime and monitored their brain activity during sleep. They found that the radiation exposure altered brainwave patterns during deep sleep, with specific frequency bands showing increased activity that persisted hours after the exposure ended. This demonstrates that cell phone radiation can cause measurable changes to brain function that outlast the actual exposure period.

Cancer & TumorsNo Effects Found

Chronic, low-level (1.0 W/kg) exposure of mice prone to mammary cancer to 2450 MHz microwaves.

Frei et al. · 1998

Researchers exposed 100 mice genetically prone to breast cancer to microwave radiation at 2450 MHz (the same frequency used in microwave ovens and early WiFi) for 78 weeks, 20 hours per day. They found no difference in cancer rates between exposed mice (38%) and unexposed mice (30%), and no difference in how quickly tumors developed or grew. This suggests that chronic exposure to this specific level of microwave radiation did not increase breast cancer risk in these cancer-prone animals.

Transactions of the Second Annual Meeting of the Bioelectrical Repair and Growth Society

Various (composite volume) · 1982

This 1982 conference brought together researchers studying how electromagnetic fields affect biological repair and growth processes. Scientists presented findings on using specific frequencies to stimulate cellular healing, reduce inflammation, and enhance immune responses. The research explored therapeutic applications of bioelectrical signals for medical treatment.

PROPOSED TLV FOR RADIOFREQUENCY RADIATION

Unknown authors · 1979

This 1979 technical report proposed threshold limit values (TLV) for radiofrequency radiation exposure in occupational settings. The document addressed workplace safety standards for microwave and RF electromagnetic energy, establishing guidelines for how much exposure workers could safely receive. This represents early efforts to regulate RF radiation before widespread consumer electronics adoption.

PROPOSED TLV FOR RADIOFREQUENCY RADIATION

Unknown authors · 1979

This 1979 technical report proposed threshold limit values (TLVs) for radiofrequency radiation exposure in occupational settings. The document addressed workplace safety standards for electromagnetic energy, particularly microwave radiation exposure limits for workers. This represents early efforts to establish science-based exposure guidelines before widespread consumer electronics adoption.

An Analysis Of Radiofrequency And Microwave Absorption Data With Consideration Of Thermal Safety Standards

Richard A. Tell · 1978

This 1978 EPA technical report analyzed how radiofrequency and microwave radiation is absorbed by biological tissue, specifically examining thermal safety standards used to protect people from heating effects. The study represents early government efforts to establish exposure limits based on the assumption that heating is the primary health concern from RF radiation.

An Analysis Of Radiofrequency And Microwave Absorption Data With Consideration Of Thermal Safety Standards

Richard A. Tell · 1978

This 1978 EPA technical report analyzed radiofrequency and microwave absorption data to evaluate thermal safety standards for human exposure. The study examined how RF and microwave energy is absorbed by biological tissue and assessed whether existing safety guidelines adequately protect against heating effects. This represents early government recognition that RF/microwave exposure needed systematic safety evaluation.

An Analysis Of Radiofrequency And Microwave Absorption Data With Consideration Of Thermal Safety Standards

Richard A. Tell · 1978

This 1978 EPA technical report analyzed radiofrequency and microwave absorption data to evaluate thermal safety standards for nonionizing radiation exposure. The research examined how RF and microwave energy is absorbed by biological tissue and whether existing safety guidelines adequately protect against heating effects. This work helped establish early foundations for RF exposure limits that remain influential in current safety standards.

AN ATTEMPT TO EVALUATE THE EXPOSURE OF OPERATORS OF PORTABLE RADIOS AT 30 MHZ

O. Balzano, O. Garay, F.R. Steel · 1970

This 1970 technical report examined RF energy exposure levels from portable radio operators using 30 MHz frequencies. Researchers used phantom models and tissue simulation techniques to measure how much radiofrequency energy was deposited in human tissue during radio operation. The study represents early efforts to quantify occupational RF exposure from handheld communication devices.

Effect of 900 MHz radıofrequency radıatıon on oxıdatıve stress in rat brain and serum

Bilgici B, Akar A, Avci B, Tuncel OK · 2013

Researchers exposed rats to 900 MHz radiofrequency radiation (the same frequency used by many cell phones) for one hour daily over three weeks at levels similar to what humans experience. They found significant increases in oxidative stress markers in the brain, indicating cellular damage from free radicals. Interestingly, rats given garlic powder showed protection against this brain damage, suggesting antioxidants may help counteract RF radiation effects.