Dose-response relationship between light irradiance and the suppression of plasma melatonin in human volunteers

Brain Res. 1988 Jun 28;454(1-2):212-8. doi: 10.1016/0006-8993(88)90820-7.


This study tested the capacity of different irradiances of monochromatic light to reduce plasma melatonin in normal humans. Six healthy male volunteers, 24-34 years old, were exposed to 0.01, 0.3, 1.6, 5, or 13 microW/cm2 of 509 nm monochromatic light for 1 h during the night on separate occasions. Light irradiance depressed plasma melatonin in a dose-response pattern. The data indicate that the mean threshold irradiance for suppressing melatonin is between 1.6 and 5 microW/cm2. Individual variations in threshold responses to monochromatic light were observed among the volunteers.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Humans
  • Lighting*
  • Male
  • Melatonin / blood*
  • Pineal Gland / metabolism
  • Pineal Gland / physiology*


  • Melatonin