Melatonin

The sleep hormone of the pineal gland. It regulates the circadian rhythm and is considered to act as an antioxidant. Production rises as darkness falls, usually in the late evening – inhibited by blue light.

How melatonin acts in the body

The pineal gland makes melatonin from serotonin, controlled by the internal clock in the hypothalamus. Light on the retina – especially short-wave blue light – slows production; as darkness falls it rises and peaks during the night. Melatonin acts via its own receptors in the brain and many organs as a time signal: it lowers core body temperature, makes falling asleep easier and aligns the organ clocks with the day-night cycle.

Low melatonin – what happens in the body?

When there is little melatonin in the evening or it rises too late, the time signal for the night is missing: falling asleep becomes harder, sleep shifts later and the organ clocks run less in sync. Causes are bright light in the evening (screens), shift work, crossing time zones, older age – production declines with the years – and some medications such as beta blockers.

High melatonin – what happens in the body?

High levels during the day indicate a shifted internal clock or melatonin intake. If melatonin stays raised in the morning, the night signal extends into the day – with tiredness and grogginess in the morning.

The interpretation is given in your report.