Melatonin regulates the Circadian clock

The hormone melatonin plays a vital role in regulating the body´s natural circadian rhythm (Ref. 1)

The melatonin level in humans:

- Increases just before onset of sleep

- Remains in high concentrations throughout the night

- Falls to almost zero during the day

 

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References

1. Cajochen C, Krauchi K, Wirz-Justice A. Role of melatonin in the regulation of human circadian rhythms and sleep. J. Neuroendocrinology 2003; 15: 432-437

2. Dijk D J, SSRC (University of Surrey, UK), Data on file