A hormone secreted by the pineal gland which inhibits melanin formation and is thought to be concerned with regulating the reproductive cycle.
- ‘Research has found the pineal hormone melatonin is low in migraine patients.’
- ‘Bright light in the morning affects your levels of the hormone melatonin.’
- ‘The pineal gland hormone, melatonin, is one of the endproducts regulated by the circadian system.’
- ‘Delaying sleep on weekends delays the nightly secretion of melatonin, the sleep hormone.’
- ‘Cherries are also a great source of melatonin, a hormone that your body uses to regulate its sleep patterns.’
1950s: from Greek melas ‘black’ + serotonin.
We take a look at several popular, though confusing, punctuation marks.