6,486 Studies Reviewed. 85.2% of Original Studies 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:

A logarithmic scale showing your reading relative to Building Biology concern thresholds and FCC regulatory limits.Your Magnetic Field Exposure in ContextNo ConcernSlightSevereExtreme0.215FCC Limit →0.0110,000 mG

Showing 486 studies with measured magnetic fields (elf) exposure

Effect of exposure to 50 Hz magnetic field with or without insulin on blood-brain barrier permeability in streptozotocin-induced diabetic rats.

Gulturk S et al. · 2010

Rats in the magnetic field groups were exposed to a 5 mT field for 165 minutes every day for 30 days, and all rats underwent Evans blue measurement to evaluate the blood-brain barrier. Diabetes and magnetic field exposure each increased blood-brain barrier permeability, their combination caused a greater increase, and insulin reduced that effect.

Extremely low frequency (ELF) magnetic fields enhance chemically induced formation of apurinic/apyrimidinic (AP)sites in A172 cells.

Koyama S, Sakurai T, Nakahara T, Miyakoshi J · 2008

Researchers measured apurinic/apyrimidinic (AP) sites in human glioma A172 cells after exposure to extremely low frequency (ELF) magnetic fields, genotoxic chemicals, or both. ELF magnetic fields alone produced no difference in AP sites compared with sham controls. The results suggest that the number of AP sites induced by MMS or H2O2 is enhanced by exposure to ELF magnetic fields at 5 millitesla (mT).

ELF electromagnetic fields increase hydrogen peroxide (H2O2)-induced mutations in pTN89 plasmids.

Koyama S et al. · 2004

Researchers tested whether an extremely low-frequency magnetic field (ELFMF) could affect mutations caused by hydrogen peroxide in pTN89 plasmids. Mutations were detected in the supF gene carried by the plasmids in Escherichia coli. The mutation frequency was 2.28×10−4 for hydrogen peroxide treatment alone, and 5.81×10−4 when the ELFMF was applied at the same time. No mutations were observed with ELFMF exposure alone, and the researchers indicated that the ELFMF may potentiate hydrogen peroxide-induced mutation.

Extremely low frequency magnetic fields and the promotion of H2O2-induced cell death in HL-60 cells.

Ding GR et al. · 2004

Researchers tested whether exposure to an extremely low frequency magnetic field affects hydrogen peroxide-induced cell death in human leukaemia HL-60 cells. Simultaneous treatment with the magnetic field and hydrogen peroxide for 24 hours significantly increased the number of apoptotic and necrotic cells compared with cells treated with hydrogen peroxide alone. The researchers found that active caspase-7 protein levels were higher in cells exposed to both the magnetic field and hydrogen peroxide than in those treated with hydrogen peroxide alone, and that poly(ADP-ribose) polymerase cleavage occurred earlier under combined exposure.

Electromagnetic field exposure (50 Hz) impairs response to noxious heat in American cockroach.

Maliszewska J et al. · 2018

Researchers studied whether a 50 Hz magnetic field affects how American cockroaches respond to noxious heat and alters oxidative stress markers. The exposure was 50 Hz at 7 mT, and the researchers measured how long cockroaches took to escape from high ambient temperature. Escape latency significantly increased after 24 hours, 72 hours, and 7 days of EMF exposure. Malondialdehyde levels increased significantly after 24-hour exposure and remained elevated up to 7 days, while glutathione levels significantly declined after 7 days of exposure.

Simultaneous application of cisplatin and static magnetic field enhances oxidative stress in HeLa cell line

Kamalipooya S et al. · 2017

Researchers studied the effects of combining a static magnetic field (SMF) with the anticancer drug cisplatin on oxidative stress in human cervical cancer cells (HeLa) and normal skin fibroblast cells (Hu02). Cells were exposed to SMF intensities of 7, 10, and 15 mT for 24 and 48 hours, and cytotoxic effects were measured using reactive oxygen species content and membrane lipid peroxidation. The combination of both treatments for 48 hours led to a marked decrease in HeLa cell viability of about 89% compared to untreated cells. The study suggests that among the optional intensities of SMF tested, the intensity of 10 mT led to higher damage to cancer cells at lower doses of the drug.

Benign Effect of Extremely Low-Frequency Electromagnetic Field on Brain Plasticity Assessed by Nitric Oxide Metabolism during Poststroke Rehabilitation

Cichoń N et al. · 2017

Patients were divided into two groups, both undergoing the same 4-week rehabilitation program, with one group also receiving daily ELF-EMF exposure. The ELF-EMF group was exposed to a field of 40 Hz and 7 mT for 15 minutes per day. ELF-EMF significantly increased 3-nitrotyrosine and nitrate/nitrite levels, while NOS2 expression was insignificantly decreased in both groups. The researchers concluded that ELF-EMF therapy is capable of promoting recovery in poststroke patients.

Benign Effect of Extremely Low-Frequency Electromagnetic Field on Brain Plasticity Assessed by Nitric Oxide Metabolism during Poststroke Rehabilitation.

Cichoń N et al. · 2017

Researchers studied 48 stroke patients undergoing rehabilitation, with half receiving additional exposure to extremely low-frequency electromagnetic fields (40 Hz) for 15 minutes daily. The EMF-exposed group showed increased levels of nitric oxide compounds in their blood and demonstrated better functional and mental recovery compared to the control group. This suggests that specific EMF frequencies might help enhance brain healing after stroke.

Extremely low frequency electromagnetic field (ELF-EMF) reduces oxidative stress and improves functional and psychological status in ischemic stroke patients.

Cichoń N, Bijak M, Miller E, Saluk J. · 2017

Researchers investigated the effect of ELF-EMF on clinical and antioxidant status in post-stroke patients. Fifty-seven patients were divided into two groups: ELF-EMF and non-ELF-EMF, and both groups underwent the same 4-week rehabilitation program. The ELF-EMF group was additionally exposed to a field of 40 Hz, 7 mT for 15 min/day for 4 weeks, 5 days a week. ELF-EMF significantly increased enzymatic antioxidant activity, though total antioxidant status levels did not change in either group.

Effect of extremely low frequency magnetic field on glutathione in rat muscles.

Ciejka E et al. · 2014

Researchers studied how an extremely low frequency magnetic field used in magnetotherapy affected glutathione levels and redox state in rat skeletal muscle. Male rats weighing 280-300 g were randomly divided into 3 experimental groups: a control group and treatment groups exposed to 40 Hz, 7 mT for either 0.5 h/day or 1 h/day for 14 days. Both 30 min/day and 60 min/day exposures significantly increased total glutathione levels in skeletal muscle compared to controls (p < 0.001).

Effects of extremely low frequency magnetic field on oxidative balance in brain of rats

Ciejka E, Kleniewska P, Skibska B, Goraca A · 2011

Researchers exposed rats to 40 Hz magnetic fields at 7 mT (milliTesla) for either 30 or 60 minutes daily over 10 days to study brain cell damage. They found that shorter exposures (30 minutes) increased harmful oxidative stress markers in the brain, while longer exposures (60 minutes) triggered protective adaptation responses. This suggests that magnetic field exposure duration significantly affects how the brain responds to electromagnetic stress.

Effects of extremely low frequency magnetic field on oxidative balance in brain of rats.

Ciejka E, Kleniewska P, Skibska B, Goraca A. · 2011

The study aimed to assess the effect of extremely low frequency magnetic field parameters on reactive oxygen species generation in brain tissue of experimental animals depending on the time of exposure. Exposure at 30 min/day for 10 days caused a significant increase in lipid peroxidation and an insignificant increase in hydrogen peroxide and free sulphydryl groups. Exposure at 60 min/day caused a significant increase in free sulphydryl groups and protein concentration, which the researchers described as indicating an adaptive mechanism.

Influence of low frequency magnetic field on chosen parameters of oxidative stress in rat's muscles.

Ciejka E, Skibska B, Kleniewska P, Goraca A. · 2010

Researchers studied the influence of a low-frequency magnetic field on oxidative stress markers in rat muscles. Thirty male rats weighing 280 to 300 grams were randomly divided into three experimental groups, each containing seven animals. One treatment group was exposed to 40 Hz and 7 mT for 0.5 hours per day for 14 days, and the other was exposed at the same settings for 1 hour per day for 14 days. Exposure caused a significant increase in sulfhydryl group concentration and a decrease in protein concentration in the muscle homogenates.

The influence of low-frequency magnetic field on plasma antioxidant capacity and heart rate.

Ciejka EB, Goraca A · 2009

The study tested whether a time-variable magnetic field affects heart rate and plasma antioxidant capacity. Tests were performed on Sprague-Dawley rats exposed to the magnetic field at a frequency of 40 Hz and induction of 7 mT for 30 and 60 minutes. A significant decrease of the heart rate was observed after 14 days of exposure. Exposure at 60 minutes for 14 days caused a significant decrease of the organism antioxidant defence.

Protective effect of melatonin and vitamin E against prooxidative action of iron ions and static magnetic field

Jajte J, Zmyślony M, Rajkowska E. · 2003

Researchers examined whether melatonin and vitamin E could protect rat blood lymphocytes from lipid peroxidation caused by iron ions and a 7 mT static magnetic field in vitro. Simultaneous exposure to the 7 mT static magnetic field and iron ions produced a significant increase in lipid peroxidation end-products compared with control samples and those exposed to the field alone. When cells were pre-treated with melatonin or vitamin E before that same exposure, lipid peroxidation was significantly reduced, and melatonin was less effective than vitamin E under these conditions.

Effect of 7 mT static magnetic field and iron ions on rat lymphocytes: apoptosis, necrosis and free radical processes.

Jajte J, Grzegorczyk J, Zmyślony M, Rajkowska E. · 2002

Researchers exposed rat blood lymphocytes to a 7 mT static magnetic field for 3 hours in Helmholtz coils, with some samples also treated with ferrous chloride at 10 μg/ml. The static magnetic field alone and iron ions alone each produced no significant effect on cell viability. When the field and iron ions were combined, there was a significant increase in apoptotic and necrotic cells and significant alterations in cell viability. The researchers suggested that a 7 mT static magnetic field in the presence of Fe2+ ions can increase the concentration of oxygen free radicals and thus may lead to cell death.

Protective effect of melatonin against in vitro iron ions and 7 mT 50 Hz magnetic field-induced DNA damage in rat lymphocytes.

Jajte J, Zmyślony M, Palus J, Dziubałtowska E, Rajkowska E. · 2001

Researchers used the alkaline comet assay to assess DNA damage in rat peripheral blood lymphocytes exposed in vitro to iron ions and a 50 Hz magnetic field. Cell samples were incubated for 3 hours in Helmholtz coils at 7 mT 50 Hz, and some were treated with ferrous chloride at 10 μg/ml during that exposure. A significant increase in cells with DNA damage was found only after simultaneous exposure to ferrous chloride and the 7 mT 50 Hz magnetic field, compared to control samples or those incubated with ferrous chloride alone. When cells were treated with melatonin before that combined exposure, the number of damaged cells was significantly reduced, with the reduction reaching about 50% at 0.5 mM and about 100% at 1.0 mM.

Influence of extremely low frequency magnetic fields on Ca2+ signaling and double messenger system in mice hippocampus and reversal function of procyanidins extracted from lotus seedpod.

Zhang H et al. · 2017

Researchers investigated the influence of a 50 Hz, 8 mT extremely low frequency magnetic field, applied 4 hours per day for 28 days, on calcium ion signaling in the hippocampus of mice. Exposure increased levels of Gi protein, IP3, DAG, PKA, PKC beta, PP2B, and intracellular calcium, while decreasing CaMK II and PKC alpha. ELF-MF exposure also decreased the level of brain-derived neurotrophic factor (BDNF), which the researchers described as playing a key role in hippocampal neuronal cell death. Oral administration of procyanidins from lotus seedpod, especially at 90 mg per kg, significantly recovered these changes and nearly reached normal levels.

Chemoprotective action of lotus seedpod procyanidins on oxidative stress in mice induced by extremely low-frequency electromagnetic field exposure.

Luo X et al. · 2016

Researchers tested whether lotus seedpod procyanidins (LSPCs) could protect mice against oxidative stress caused by extremely low-frequency electromagnetic field (ELF-EMF) exposure. Mice were exposed to ELF-EMF at 8 mT, 4 hours per day for 28 consecutive days, and blood and cerebral cortex were analyzed for antioxidant indices. LSPCs treatment augmented SOD, CAT, GSH-Px, GR and GST activity and significantly lowered MDA levels.

Neuroprotective effects of lotus seedpod procyanidins on extremely low frequency electromagnetic field-induced neurotoxicity in primary cultured hippocampal neurons.

Yin C, Luo X, Duan Y, Duan W, Zhang H, He Y, Sun G, Sun X · 2016

Researchers investigated whether lotus seedpod procyanidins (LSPCs) could protect primary cultured rat hippocampal neurons from extremely low frequency electromagnetic field (ELF-EMF)-induced neurotoxicity. ELF-EMF exposure significantly decreased cell viability and increased the number of apoptotic cells compared with control. LSPCs evidently protected the hippocampal neurons against ELF-EMF-induced cell damage, and the researchers concluded this occurred through inhibiting oxidative stress and a mitochondrial apoptotic pathway.

Extremely low frequency electromagnetic field exposure causes cognitive impairment associated with alteration of the glutamate level, MAPK pathway activation and decreased CREB phosphorylation in mice hippocampus: reversal by procyanidins extracted from the lotus seedpod.

Duan Y, Wang Z, Zhang H, He Y, Fan R, Cheng Y, Sun G, Sun X. · 2014

Researchers exposed mice to 50 Hz magnetic fields (the same frequency as power lines) for 28 days and found significant brain changes in the hippocampus, a region critical for memory and learning. The exposure disrupted brain chemistry by increasing glutamate levels and damaging cellular signaling pathways that are essential for proper brain function. Importantly, the study also showed that these harmful effects could be reversed with a natural antioxidant treatment.

Extremely low frequency electromagnetic field exposure causes cognitive impairment associated with alteration of the glutamate level, MAPK pathway activation and decreased CREB phosphorylation in mice hippocampus: reversal by procyanidins extracted from the lotus seedpod

Duan Y, Wang Z, Zhang H, He Y, Fan R, Cheng Y, Sun G, Sun X. · 2014

Researchers studied whether exposure to a 50 Hz, 8 mT extremely low frequency electromagnetic field for 28 days altered glutamate release in mice hippocampus and whether treatment with lotus seedpod procyanidins (LSPCs) could normalize those changes. Exposure increased glutamate, GABA, NMDA receptor 2B levels, and intracellular calcium concentration in the hippocampus, while decreasing ERK1/2 and CREB phosphorylation. Oral administration of LSPCs, especially at 60 and 90 mg per kilogram, markedly improved expressions of p-CREB, p-ERK1/2, and p-JNK1/2, and was accompanied by decreased levels of glutamate, GABA, intracellular calcium, and NR2B.

The preventive effect of lotus seedpod procyanidins on cognitive impairment and oxidative damage induced by extremely low frequency electromagnetic field exposure.

Duan Y, Wang Z, Zhang H, He Y, Lu R, Zhang R, Sun G, Sun X. · 2013

Researchers exposed mice to 50 Hz magnetic fields (the type from power lines) for 28 days and found it damaged their learning, memory, and brain cells through oxidative stress. When mice were given lotus seedpod antioxidants during exposure, these harmful effects were largely prevented. This suggests that extremely low frequency EMF exposure can cause measurable brain damage, but antioxidants may offer some protection.