No measurable impact of acute 26 GHz 5G exposure on salivary stress markers in healthy adults

Environ Res · 2026 · No effect · Moderate evidence

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No effectModerate evidencePaper 2479

Study snapshot

PublicationEnviron Res · 2026

Study typerandomized_trial

Reported directionNo effect

Evidence ratingModerate

Abstract

Category: Epidemiology Tags: 5G, electromagnetic fields, RF exposure, salivary biomarkers, stress, cortisol, alpha-amylase DOI: 10.1016/j.envres.2025.123439 URL: pubmed.ncbi.nlm.nih.gov Overview The rapid deployment of fifth generation (5G) wireless networks has raised concerns about potential health effects associated with exposure to novel radiofrequency electromagnetic field (RF) frequencies, particularly the 26 GHz band, representing a new exposure scenario for the general population. Prior use in telecommunications of this frequency is limited, so current evidence for acute biological impact remains scarce and inconclusive. This fact highlights a crucial need for ongoing studies to monitor for health risks and guide EMF safety standards. Findings - Objective: This study assessed whether short-term (26.5 minutes) 5G RF exposure at 26 GHz, at levels similar to real-world environmental exposure, affects salivary cortisol and alpha-amylase—both established biomarkers of stress and autonomic nervous system activity. - Methods: Thirty-one healthy adults participated in a triple-blind, randomized protocol, including EEG measurements. Sixteen of them also took part in an exploratory protocol with cognitive assessment and high temporal sampling (every 5 minutes). - Results: Saliva samples collected before, during, and after RF/sham exposure were analyzed. Exposure levels were 2 V/m (head) and 1 V/m (torso), simulating upper-range environmental exposures. - Analysis: No significant differences in salivary cortisol or alpha-amylase concentrations were found between real and sham exposures. Analysis of the cognitive protocol group revealed no temporal changes, indicating biomarker stability under both conditions. Conclusion - Findings suggest that acute 26 GHz 5G RF exposure does not elicit measurable changes in the tested stress biomarkers in healthy adults, under rigorous and controlled laboratory conditions. - It is important to note that this study only addresses short-term exposure. Further research is warranted to evaluate repeated or long-term exposures—especially in vulnerable populations—recognizing the ongoing link between EMF exposure and health considerations. Highlights - 26.5-min 5G exposure at 26 GHz showed no effect on salivary cortisol levels. - No changes seen in alpha-amylase levels in healthy adults. - Rigorous design controlled potential confounding variables. - No acute stress effects detected from 26 GHz 5G exposure. - More research needed for long-term effects and at-risk groups.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typerandomized_trial

Effect directionno_effect

PopulationHealthy adults

Sample size31

ExposuremmWave · 26000 MHz · 26.5 min

Evidence strengthModerateConfidence: 78% · Peer reviewed: yes

Main findings

In a triple-blind randomized protocol, acute 26 GHz 5G RF exposure (26.5 min) at 2 V/m (head) and 1 V/m (torso) showed no significant differences versus sham in salivary cortisol or alpha-amylase measured before, during, and after exposure. An exploratory subset with higher temporal sampling (5-min intervals) showed descriptive temporal stability of both biomarkers in real and sham conditions.

Outcomes measured

Salivary cortisol
Salivary alpha-amylase

Limitations

Acute/short-term exposure only (26.5 min)
Subset exploratory protocol described descriptively (no inferential results reported)
Healthy adult participants only; vulnerable populations not assessed
No SAR reported; exposure characterized by field strength (V/m)

View raw extracted JSON

{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "mmWave",
    "source": "5G",
    "frequency_mhz": 26000,
    "sar_wkg": null,
    "duration": "26.5 min"
  },
  "population": "Healthy adults",
  "sample_size": 31,
  "outcomes": [
    "Salivary cortisol",
    "Salivary alpha-amylase"
  ],
  "main_findings": "In a triple-blind randomized protocol, acute 26 GHz 5G RF exposure (26.5 min) at 2 V/m (head) and 1 V/m (torso) showed no significant differences versus sham in salivary cortisol or alpha-amylase measured before, during, and after exposure. An exploratory subset with higher temporal sampling (5-min intervals) showed descriptive temporal stability of both biomarkers in real and sham conditions.",
  "effect_direction": "no_effect",
  "limitations": [
    "Acute/short-term exposure only (26.5 min)",
    "Subset exploratory protocol described descriptively (no inferential results reported)",
    "Healthy adult participants only; vulnerable populations not assessed",
    "No SAR reported; exposure characterized by field strength (V/m)"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "5G",
    "26 GHz",
    "mmWave",
    "radiofrequency electromagnetic field",
    "acute exposure",
    "triple-blind",
    "randomized",
    "sham exposure",
    "salivary cortisol",
    "alpha-amylase",
    "stress biomarkers",
    "autonomic nervous system",
    "EEG",
    "horn antenna",
    "environmental exposure levels"
  ],
  "suggested_hubs": [
    {
      "slug": "5g-policy",
      "weight": 0.62,
      "reason": "Study evaluates acute health-related biomarkers under realistic 26 GHz 5G exposure conditions relevant to public concerns/policy."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.envres.2025.123439
PubMed: 41317834

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