Study type: Medical/biological study (experimental study)

Influence of electromagnetic fields emitted by GSM-900 cellular telephones on the circadian patterns of gonadal, adrenal and pituitary hormones in men med./bio.

Published in: Radiat Res 2008; 169 (3): 337-343

Aim of study (acc. to author)

This study should examine whether the exposure to 900 MHz GSM electromagnetic fields induces changes in hormone levels in men.

Background/further details

20 healthy male volunteers in the age of 20 to 32 years participated in this study. To account physiological circadian alterations in the hormone levels blood samples were collected hourly during the night and every 3 hours during the day. Each individual's hormone concentration before the exposure was used as his control.



Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 2 h/day, 5 days/week, for 4 weeks

Exposure 1

Main characteristics
Frequency 900 MHz
Exposure duration repeated daily exposure, 2 h/day, 5 days/week, for 4 weeks
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Additional info


Exposure setup
Exposure source
Chamber During the exposure sessions, the attention of the volunteers and a correct normal use position of the mobile phone were maintained by TV projection of movies. The audio signal from the TV set was distributed to four fixed telephones that could be called from the GSM handsets to hear the movie soundtrack.
Setup For each subject, exposure was on the same side of the head for all sessions.
Sham exposure A sham exposure was conducted.
Additional info A sham exposure was also performed on the days of the first and the last blood drawing sessions by switching the RF output to a 50-Ω dummy load instead of the antenna and presenting the movie sound directly on the TV speakers.
Measurand Value Type Method Mass Remarks
power 2 W peak value - - -
SAR 0.3 W/kg average over time - 10 g in the temporal brain

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

There were significant decreases in growth hormone and cortisol levels in the 2-week exposure period and for growth hormone additionally in the 4-week exposure period. However, these differences did not persist in the period after the exposure.
No changes were observed in other investigated hormones neither in hormone concentration nor in circadian pattern.

Study character:

Study funded by

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