Melatonin: Marvel or marker?

Daniel F. Kripke, Jeffrey A. Elliott, Shawn D. Youngstedt, Julian S. Smith

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Melatonin blanches the skin of frogs, whitens the fur of hamsters, and sometimes makes the gonads atrophy. It is remarkable that such a hormone would be put forward as a defense against ageing. We have been examining excretion of the urinary metabolite of melatonin, 6-sulphatoxymelatonin (6-SMT), in 150 postmenopausal women, in 72 volunteers over the age of 60 years who complained of insomnia or depression, and in 20 healthy younger adult controls, aged 18-40 years. The acrophase or fitted peak of 6-SMT excretion was computed as a marker of the timing of the circadian system. Total daily excretion of 6-SMT was not significantly related to total sleep time, wake-within-sleep or sleep complaints. Nevertheless, whereas the 20 controls displayed a normal range of 6-SMT acrophases from 01.32 to 05.44 h, 42% of the postmenopausal women and 48% of the symptomatic elders had acrophases outside this normal range. Those volunteers with more deviant acrophases displayed more disturbed sleep and more sleep complaints. These data suggest that melatonin is a useful marker of circadian rhythm phase disorders, but suggest a need for more caution in melatonin administration.

Original languageEnglish (US)
Pages (from-to)81-87
Number of pages7
JournalAnnals of Medicine
Issue number1
StatePublished - 1998
Externally publishedYes


  • Ageing
  • Circadian rhythm
  • Insomnia
  • Melatonin
  • Sleep
  • Sulphatoxymelatonin

ASJC Scopus subject areas

  • Medicine(all)


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