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Measurement of the dielectric properties of the epidermis and dermis at frequencies from 0.5 GHz to 110 GHz.

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Sasaki K, Wake K, Watanabe S · 2014

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Current safety models significantly underestimate electromagnetic absorption in human skin at 5G frequencies, revealing gaps in exposure assessments.

Plain English Summary

Summary written for general audiences

Researchers measured how electromagnetic waves interact with the two main layers of human skin - the outer epidermis and deeper dermis - across frequencies from 0.5 to 110 GHz. They found that current safety models significantly underestimate how much electromagnetic energy these skin layers actually absorb, especially at higher frequencies above 20 GHz. This matters because accurate absorption data is crucial for both medical device development and safety assessments of wireless technologies.

Why This Matters

This research reveals a critical gap in our understanding of how EMF interacts with human tissue. The finding that existing safety models underestimate electromagnetic absorption in skin layers by significant margins at higher frequencies should concern anyone following the rollout of 5G and millimeter wave technologies. These frequencies (20-110 GHz) overlap directly with those used in emerging wireless applications, yet our safety standards rely on outdated absorption models that this study shows are inadequate. What this means for you is that exposure assessments for newer wireless technologies may be based on flawed assumptions about how deeply and intensively these frequencies penetrate skin tissue. The science demonstrates that we need updated biological interaction data before, not after, widespread deployment of these technologies.

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 500 MHz - 110 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 500 MHz - 110 GHzPower lines50/60 HzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study. The study examined exposure from: 0.5 GHz to 110 GHz

Study Details

Numerous studies have reported the measurements of the dielectric properties of the skin. Clarifying the manner in which the human body interacts with electromagnetic waves is essential for medical research and development, as well as for the safety assessment of electromagnetic wave exposure. The skin comprises several layers: the epidermis, the dermis, and the subcutaneous fat. Each of these skin layers has a different constitution; however, the previous measurements of their dielectric properties were typically conducted on tissue which included all three layers of the skin. This study presents novel dielectric property data for the epidermis and dermis with in vitro measurement at frequencies ranging from 0.5 GHz to 110 GHz.

Measured data was compared with literature values; in particular, the findings were compared with Ga...

The experimental results agreed with the data reported by Gabriel for the dermis of up to 20 GHz, wh...

Cite This Study
Sasaki K, Wake K, Watanabe S (2014). Measurement of the dielectric properties of the epidermis and dermis at frequencies from 0.5 GHz to 110 GHz. Phys Med Biol. 59(16):4739-4747, 2014.
Show BibTeX
@article{k_2014_measurement_of_the_dielectric_2567,
  author = {Sasaki K and Wake K and Watanabe S},
  title = {Measurement of the dielectric properties of the epidermis and dermis at frequencies from 0.5 GHz to 110 GHz.},
  year = {2014},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/25082800/},
}
PubMed: 25082800

Cited By (74 papers)

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Quick Questions About This Study

Yes, 2014 research shows current safety models underestimate how much electromagnetic energy skin absorbs at 5G frequencies above 20 GHz. The outer epidermis and deeper dermis layers absorb significantly more radiation than previously calculated in safety assessments.
Studies measuring skin interaction with millimeter waves (20-110 GHz) found that both epidermis and dermis layers absorb more electromagnetic energy than safety models predict. This suggests current exposure limits may not accurately reflect actual skin absorption rates.
Research indicates SAR (Specific Absorption Rate) models significantly underestimate electromagnetic absorption in human skin, especially at frequencies above 20 GHz. Experimental measurements showed higher absorption values than those used in current safety calculations.
While this study didn't measure biological damage directly, it found that skin absorbs much more high-frequency electromagnetic energy than safety models assume. This discrepancy raises questions about whether current exposure limits adequately protect skin tissue.
Yes, researchers found that the epidermis (outer skin) and dermis (deeper layer) have different electromagnetic absorption properties than previously measured. Both layers absorb more radiation at higher frequencies than current safety models account for.