# melatonin

/ˌmɛɫəˈtoʊnɪn/ (US) · /mˈɛlɐtˌɒnɪn/ (UK) · CEFR B2 · Noun

Source: https://englishreference.com/word/melatonin
Updated: 2026-05-18

## Definition

a natural chemical in your body that helps you fall asleep. It is often found in supplements to help people with sleep problems.

For teachers: a hormone secreted by the pineal gland that regulates the sleep-wake cycle. It is also available as a pharmaceutical supplement to treat insomnia and jet lag.

## Examples

- I take a melatonin tablet an hour before bed to help me sleep.
- Many people use melatonin supplements when traveling across time zones to adjust their internal clocks more quickly.
- While melatonin is effective for short-term sleep regulation, long-term reliance on synthetic supplements may disrupt the body's natural circadian rhythms if not managed carefully.

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