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Note: This study found no significant biological effects under its experimental conditions. We include all studies for scientific completeness.

Brain & Nervous System

Biomarkers in volunteers exposed to mobile phone radiation.

No Effects Found

Söderqvist F, Carlberg M, Hardell L · 2015

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No blood-brain barrier effects found in regular cell phone users, but study couldn't test truly unexposed individuals.

Plain English Summary

Summary written for general audiences

Swedish researchers tested whether cell phone radiation affects the blood-brain barrier (the brain's protective shield) by measuring specific proteins in blood samples from 24 volunteers before and after exposure to phone-like signals. The study found no significant differences in these barrier-protecting proteins between real exposure and fake exposure sessions. However, the researchers noted that all participants were regular cell phone users, which may have influenced the results.

Why This Matters

This study represents a rare attempt to examine blood-brain barrier effects in humans rather than laboratory animals, addressing one of the most concerning potential mechanisms of EMF harm. The blood-brain barrier protects our brain from toxins, and any compromise could have serious neurological implications. While this study found no acute effects, the researchers themselves highlight a critical limitation: all participants were chronic cell phone users. The science demonstrates that prior EMF exposure can alter biological responses, making it difficult to detect additional effects in already-exposed populations. What this means for you is that we still lack definitive human data on blood-brain barrier effects in EMF-naive individuals. The exposure levels tested (0.2 to 2 W/kg SAR) span the range of typical cell phone use, making these findings relevant to everyday exposure scenarios.

Exposure Details

SAR
2, 0.2 W/kg
Source/Device
890-MHz

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 2, 0.2 W/kgExtreme Concern - 0.1 W/kgFCC Limit - 1.6 W/kgEffects observed in the Extreme Concern range (Building Biology)FCC limit is 8 times higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 890 MHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 890 MHzPower lines50/60 Hz5G mm28 GHzLogarithmic scale

Study Details

For some time it has been investigated whether low-intensity non-thermal microwave radiation from mobile phones adversely affects the mammalian blood–brain barrier (BBB). All such studies except one have been either in vitro or experimental animal studies. The one carried out on humans showed a statistically significant increase in serum transthyretin (TTR) 60 min after finishing of a 30-min microwave exposure session. The aim of the present study was to follow up on the finding of the previous one using a better study design

Using biomarkers analyzed in blood serum before and after the exposure this single blinded randomize...

Over time, statistically significant variations were found for two of the three biomarkers (TTR; β-t...

In conclusion this study failed to show any acute clinically or statistically significant effect of short term microwave exposure on the serum levels of S100β, TTR and β-trace protein with a follow up limited to two hours. The study was hampered by the fact that all study persons were regular wireless phone users and thus not naïve as to microwave exposure.

Cite This Study
Söderqvist F, Carlberg M, Hardell L (2015). Biomarkers in volunteers exposed to mobile phone radiation. Toxicol Lett. 2015 Mar 31. pii: S0378-4274(15)00119-8. doi: 10.1016/j.toxlet.2015.03.016.
Show BibTeX
@article{f_2015_biomarkers_in_volunteers_exposed_3409,
  author = {Söderqvist F and Carlberg M and Hardell L},
  title = {Biomarkers in volunteers exposed to mobile phone radiation.},
  year = {2015},
  
  url = {https://www.sciencedirect.com/science/article/abs/pii/S0378427415001198},
}

Quick Questions About This Study

A 2015 Swedish study found no significant effects of 890 MHz radiation on blood-brain barrier proteins in 24 volunteers. Researchers measured barrier-protecting proteins before and after exposure to phone-like signals, finding no differences between real and fake exposure sessions.
Swedish researchers measured S100β protein levels in blood samples to detect potential brain barrier damage from 890 MHz radiation. The study found no clinically or statistically significant changes in S100β levels after short-term microwave exposure in regular cell phone users.
Researchers followed participants for two hours after 890 MHz radiation exposure, finding no acute effects on barrier proteins. The study's limited follow-up period means longer-term effects on the blood-brain barrier remain unknown and require further investigation.
The 2015 Swedish study noted that all participants were regular wireless phone users, which may have influenced results. Researchers acknowledged this limitation, suggesting that people already adapted to microwave exposure might respond differently than EMF-naive individuals.
Researchers tested three blood biomarkers: S100β, TTR, and β-trace protein to assess blood-brain barrier integrity after 890 MHz exposure. While two markers showed time-related variations, none showed significant differences between real and sham radiation exposure conditions.