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Sleep & Circadian Rhythm

GSM modulated radiofrequency radiation does not affect 6-sulfatoxymelatonin excretion of rats.

No Effects Found

Bakos J, Kubinyi G, Sinay H, Thuroczy G. · 2003

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Cell phone-level radiation showed no immediate effects on melatonin production in rats after 14 days of exposure.

Plain English Summary

Summary written for general audiences

Researchers exposed 72 rats to cell phone-type radiation at 900 MHz and 1800 MHz for 2 hours daily over 14 days, then measured melatonin breakdown products in their urine to see if the radiation disrupted their natural sleep hormone production. They found no significant changes in melatonin levels compared to unexposed control rats. This suggests that short-term exposure to these specific radiation levels may not immediately disrupt the body's internal clock or sleep patterns.

Why This Matters

This study addresses a critical question about whether cell phone radiation disrupts melatonin production, which regulates our sleep-wake cycles. The power densities used (100 μW/cm² at 900 MHz) are actually higher than typical cell phone exposures during calls, making this a meaningful test of potential sleep disruption. However, the 14-day exposure period represents relatively short-term effects, and we know from other research that EMF impacts on circadian rhythms can be subtle and may require longer observation periods to detect. While this negative result is reassuring, it doesn't close the book on EMF sleep effects. The broader body of research includes studies showing EMF impacts on sleep quality and melatonin production under different conditions, suggesting the relationship between radiofrequency exposure and circadian disruption remains an active area of scientific investigation.

Exposure Details

Power Density
0.1 mW/cm²
Source/Device
900 MHz
Exposure Duration
2 h between 8:00 AM and noon daily during the 14 day exposure

Exposure Context

This study used 0.1 mW/cm² for radio frequency:

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 0.1 mW/cm²Extreme Concern - 1,000 µW/m²FCC Limit - 10M µW/m²Effects observed in the Extreme Concern range (Building Biology)FCC limit is 10 times higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 900 MHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 900 MHzPower lines50/60 Hz5G mm28 GHzLogarithmic scale

Study Details

In this study, the effect of exposure to 900 and 1800 MHz GSM-like radiofrequency radiation upon the urinary 6-sulfatoxymelatonin (6SM) excretion of adult male Wistar rats was studied.

Seventy-two rats were used in six independent experiments, three of which were done with 900 MHz and...

The combined results of three experiments done with the same frequency were statistically analyzed. ...

Cite This Study
Bakos J, Kubinyi G, Sinay H, Thuroczy G. (2003). GSM modulated radiofrequency radiation does not affect 6-sulfatoxymelatonin excretion of rats. Bioelectromagnetics 24(8):531-534, 2003.
Show BibTeX
@article{j_2003_gsm_modulated_radiofrequency_radiation_2949,
  author = {Bakos J and Kubinyi G and Sinay H and Thuroczy G.},
  title = {GSM modulated radiofrequency radiation does not affect 6-sulfatoxymelatonin excretion of rats.},
  year = {2003},
  doi = {10.1002/bem.10172},
  url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/bem.10172},
}
DOI: 10.1002/bem.10172

Cited By (24 papers)

Quick Questions About This Study

A 2003 study found that cell phone radiation at 900 MHz and 1800 MHz did not affect melatonin production in rats after 14 days of exposure. The researchers measured melatonin breakdown products in urine and found no significant changes compared to unexposed animals.
Research on 72 rats exposed to 900 MHz radiation for 2 hours daily over 14 days showed no disruption to melatonin production. Scientists measured 6-sulfatoxymelatonin in urine and found no statistically significant differences between exposed and control groups.
One study suggests short-term cell phone radiation exposure may not immediately disrupt circadian rhythms. Researchers exposed rats to 900 MHz and 1800 MHz frequencies for 14 days and found no changes in melatonin levels, which regulate the body's internal clock.
A controlled study found no immediate sleep hormone disruption from cell phone-type radiation at 900 MHz and 1800 MHz frequencies. However, this was a short-term animal study, and more research is needed to understand long-term effects on human sleep patterns.
Research measuring melatonin production in rats found no impact from 14 days of radiofrequency exposure at cell phone frequencies. The study examined 900 MHz and 1800 MHz radiation but was limited to short-term exposure in animal subjects.