3,138 Studies Reviewed. 77.4% Found Biological Effects. The Evidence is Clear.
All Exposure Types

Magnetic Fields (ELF)

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Extremely Low Frequency (ELF) magnetic fields are produced by the flow of electrical current. They are measured in milligauss (mG) or microtesla (µT). Unlike electric fields, magnetic fields easily penetrate walls and most materials.

Concern Level Thresholds

Based on Building Biology Institute guidelines (mG (milligauss)):

No Concern
< 0.2 mG
Slight Concern
0.2 – 1 mG
Severe Concern
1 – 5 mG
Extreme Concern
> 5 mG

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 ConcernSlightSevereExtreme0.215FCC Limit 0.0110,000 mG

Showing 443 studies with measured magnetic fields (elf) exposure

Whole Body / GeneralNo Effects Found

TYPICAL EXPOSURE OF CHILDREN TO EMF: EXPOSIMETRY AND DOSIMETRY.

Valič B, Kos B, Gajšek P. · 2014

Researchers measured EMF exposure in 21 children under 17 using portable devices worn for over 2,400 hours total. They found average exposures were very low compared to safety guidelines - less than 0.03% for power line frequencies and less than 0.001% for wireless signals like WiFi and cell towers. Even the highest exposures recorded were still well below 1% of current safety limits.

Nitric oxide modulates the responses of osteoclast formation to static magnetic fields

Zhang J, Ding C, Meng X, Shang P · 2018

Researchers exposed bone cells to three different strengths of static magnetic fields to study how they affect osteoclast formation (cells that break down bone tissue). They found that very strong magnetic fields (16 Tesla) reduced osteoclast formation through increased nitric oxide production, while weaker fields (500 nT and 0.2 T) had the opposite effect. This suggests magnetic fields can influence bone health by altering cellular signaling pathways.

Increased levels of hsp70 transcripts induced when cells are exposed to low frequency electromagnetic fields

R. Goodman et al. · 1994

Researchers exposed human and yeast cells to extremely low frequency magnetic fields (0.0008 to 0.08 millitesla) and found that these fields triggered the production of heat shock proteins - cellular stress response molecules normally produced when cells are damaged by heat or toxins. The cells responded to EMF exposure as if they were under biological stress, activating the same protective mechanisms they use against harmful conditions.

Effects of exposure to extremely low-frequency electromagnetic fields on spatial and passive avoidance learning and memory, anxiety-like behavior and oxidative stress in male rats.

Karimi SA, Salehi I, Shykhi T, Zare S, Komaki A. · 2019

Researchers exposed male rats to extremely low-frequency electromagnetic fields (ELF-EMF) for 2 hours daily over 60 days at various intensities. They found that certain exposure levels improved memory retention and passive learning, but also increased anxiety-like behaviors and oxidative stress (cellular damage from unstable molecules). This suggests ELF-EMF exposure creates a complex mix of both beneficial and harmful effects on brain function.

Whole Body / GeneralNo Effects Found

Preliminary background indoor EMF measurements in Greece.

Kottou S et al. · 2015

Greek researchers measured electromagnetic field levels in over 4,500 indoor locations across three regions, focusing on extremely low frequency magnetic fields and radiofrequency electric fields that health agencies consider possibly cancer-causing. They found that while EMF levels varied by location and distance from sources, all measurements remained well below current safety limits set by European regulators. The study provides baseline data on typical indoor EMF exposure levels in Greek homes.

Brain & Nervous SystemNo Effects Found

Assessment of the neurotoxic potential of exposure to 50 Hz extremely low frequency electromagnetic fields (ELF-EMF) in naïve and chemically-stressed PC12 cells.

de Groot MW, Kock MD, Westerink RH. · 2014

Researchers exposed nerve cells (PC12 cells) to 50 Hz magnetic fields at levels up to 1,000 microtesla for periods ranging from 30 minutes to 48 hours. They tested both healthy cells and chemically-stressed cells that were more vulnerable to damage. The magnetic field exposure caused no detectable effects on calcium levels, cellular damage, or oxidative stress in either type of cell.

Effects of extremely low-frequency electric fields at different intensities and exposure durations on mismatch negativity.

Kantar Gok D et al. · 2014

Researchers exposed rats to 50 Hz electric fields (like those from power lines) for up to four weeks. High-intensity exposure significantly reduced brain responses that help detect sound changes, while increasing brain damage markers. This suggests electric field exposure may impair auditory processing abilities.

Physiologically patterned weak magnetic fields applied over left frontal lobe increase acceptance of false statements as true.

Ross ML, Koren SA, Persinger MA. · 2008

Researchers exposed 50 people to weak magnetic fields over their left forehead while they processed true or false statements about word definitions. Those exposed to specific pulsed magnetic field patterns (25 Hz or burst-firing) were twice as likely to later accept false statements as true compared to control groups. This demonstrates that extremely weak magnetic fields can directly influence cognitive judgment and decision-making processes in the brain.

Personal digital assistant (PDA) cell phone units produce elevated extremely-low frequency electromagnetic field emissions.

Sage C, Johansson O, Sage SA · 2007

Researchers measured electromagnetic fields from early smartphone-like devices during normal use. They found these devices produced surprisingly high electromagnetic pulses - up to 90 microTesla when powering on and 60 microTesla during email activities - potentially exposing users throughout day and night.

Effect of centimeter microwaves and the combined magnetic field on the tumor necrosis factor production in cells of mice with experimental tumors

Novoselova EG, Ogai VB, Sorokina OV, Novikov VV, Fesenko EE · 2001

Researchers exposed tumor-bearing mice to extremely low-level microwaves (1 microW/cm2) combined with weak magnetic fields for 1.5 hours daily over 7 days. They found that this dual exposure increased production of tumor necrosis factor, a protein that helps the immune system fight cancer cells. The results suggest that certain EMF exposures might actually enhance the body's natural tumor-fighting response.

Superposition of an incoherent magnetic field inhibited EGF receptor clustering and phosphorylation induced by a 1.8 GHz pulse-modulated radiofrequency radiation.

Sun W, Shen X, Lu D, Lu D, Chiang H · 2013

Researchers exposed human cells to 1.8 GHz radiofrequency radiation (similar to cell phone signals) and found it triggered abnormal clustering and activation of cellular receptors that control cell growth. Interestingly, when they added a weak 'noise' magnetic field alongside the RF exposure, it completely blocked these cellular changes at moderate power levels, suggesting the magnetic field provided some protection against RF-induced cellular disruption.

Electromagnetic noise inhibits radiofrequency radiation-induced DNA damage and reactive oxygen species increase in human lens epithelial cells.

Yao K, Wu W, Wang K, Ni S, Ye P, Yu Y, Ye J, Sun L. · 2008

Researchers exposed human eye lens cells to 1.8 GHz radiofrequency radiation (the frequency used by GSM cell phones) at power levels of 1-4 watts per kilogram for 2 hours. They found that higher exposure levels caused DNA damage and increased harmful molecules called reactive oxygen species in the cells. Interestingly, when they added electromagnetic 'noise' to the radiation, it prevented these cellular damage effects.

Blocking 1800 MHz mobile phone radiation-induced reactive oxygen species production and DNA damage in lens epithelial cells by noise magnetic fields.

Wu W, Yao K, Wang KJ, Lu DQ, He JL, Xu LH, Sun WJ. · 2008

Researchers exposed human eye lens cells to cell phone radiation at levels four times higher than safety limits and found it caused DNA damage and increased harmful reactive oxygen species (molecules that damage cells). However, when they simultaneously exposed the cells to electromagnetic noise fields, this completely blocked the DNA damage and cellular harm from the phone radiation.

Bioeffects induced by exposure to microwaves are mitigated by superposition of ELF noise.

Litovitz et al. · 1997

Researchers exposed cells to microwave radiation from cell phones and found it increased activity of an enzyme called ornithine decarboxylase, which is linked to cell growth and potentially cancer. However, when they added low-frequency electromagnetic 'noise' during the exposure, it completely blocked these cellular effects. This suggests that certain types of electromagnetic interference might actually protect cells from microwave damage.

Electromagnetic fields instantaneously modulate nitric oxide signaling in challenged biological systems.

Pilla AA · 2012

Researchers exposed brain cells to radiofrequency electromagnetic fields at 27.12 MHz and found the fields instantly triggered a nearly 3-fold increase in nitric oxide production. Nitric oxide is a crucial signaling molecule that helps regulate blood flow, immune responses, and healing processes in the body. The study shows that EMF exposure can immediately alter fundamental cellular communication pathways.

Assessment of biological changes of continuous whole body exposure to static magnetic field and extremely low frequency electromagnetic fields in mice.

Hashish AH, El-Missiry MA, Abdelkader HI, Abou-Saleh RH · 2008

Researchers exposed mice to static magnetic fields and 50 Hz electromagnetic fields (like those from power lines) continuously for 30 days to study health effects. The exposed mice lost weight, showed signs of liver stress including increased oxidative damage, and had significant changes in their blood cells and immune system markers. The study demonstrates that prolonged exposure to these common electromagnetic fields can disrupt normal body functions through oxidative stress.

Mobile-phone pulse triggers evoked potentials

Carrubba S, Frilot C 2nd, Chesson AL Jr, Marino AA · 2010

Researchers exposed 20 volunteers to mobile phone pulses (217 Hz frequency) while monitoring brain activity. Advanced analysis detected measurable brain responses in 90% of participants, suggesting mobile phones create detectable changes in brain function that standard testing methods miss.

Interaction of Microwaves and a Temporally Incoherent Magnetic Field on Single and Double DNA Strand Breaks in Rat Brain Cells.

Lai H, Singh NP · 2005

Researchers exposed rats to cell phone-frequency microwaves (2450 MHz) for 2 hours and found significant DNA damage in brain cells. However, when they simultaneously exposed the rats to a weak magnetic field with random fluctuations, it completely blocked the DNA damage from occurring. This suggests that certain types of magnetic field exposure might actually protect against some forms of EMF damage.

Interaction of microwaves and a temporally incoherent magnetic field on single and double DNA strand breaks in rat brain cells

Lai H, Singh NP · 2005

Researchers exposed rats to microwave radiation at cell phone frequencies (2450 MHz) for 2 hours and found significant DNA damage in brain cells. However, when they simultaneously exposed the rats to a weak magnetic field with random fluctuations, it completely blocked the DNA damage from occurring. This suggests that certain types of magnetic field exposure might actually protect against microwave-induced genetic damage.

The effect of melatonin on body mass and behaviour of rats during an exposure to microwave radiation from mobile phone.

Sokolovic D et al. · 2012

Researchers exposed rats to mobile phone radiation for 4 hours daily over 60 days and found the animals lost significant body weight and developed anxiety-like behaviors including agitation and irritability. When rats were given melatonin (a natural hormone) along with the radiation exposure, these negative effects were largely prevented, suggesting melatonin may offer protective benefits against microwave radiation damage.

Comparisons of Responses by Planarian to Micromolar to Attomolar Dosages of Morphine or Naloxone and/or Weak Pulsed Magnetic Fields: Revealing Receptor Subtype Affinities and Nonspecific Effects.

Murugan NJ, Persinger MA. · 2014

Researchers exposed flatworms (planaria) to extremely weak magnetic fields (5 microTesla) for 2 hours and measured their movement speed. The magnetic field exposure reduced the worms' activity by about 50%, similar to the effects of morphine and other opioid drugs. This suggests that weak magnetic fields can affect nervous system function in ways that mimic drug effects.

Affective response to 5 microT ELF magnetic field-induced physiological changes.

Stevens P · 2007

Researchers exposed people to extremely low frequency magnetic fields at 5 microTesla (similar to standing near some household appliances) pulsing at brain wave frequencies of 8-12 Hz. Participants reported changes in their emotional state during exposure, and brain measurements showed altered electrical activity patterns. This suggests that even relatively weak magnetic fields can influence both how people feel and measurable brain function.