A sleep hormone used for insomnia and jet lag
Melatonin
A version of the body’s natural sleep hormone — used mainly for short-term insomnia in older adults, for sleep problems in some children, and for jet lag.
What is Melatonin?
Melatonin is a manufactured form of the hormone the body makes at night to signal that it is time to sleep. It is used mainly for short-term insomnia in adults over 55, for sleep problems in some children (particularly those with certain neurodevelopmental conditions, under specialist care), and for jet lag. It works best taken at a consistent time before bed and is generally well tolerated and non-addictive.
Education and reference only. This is a plain-language guide to Melatonin — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Melatonin is a hormone the brain’s pineal gland naturally releases in the evening to help set the body’s internal clock and prepare it for sleep. As a medicine, it is used to help with sleep problems — most commonly short-term insomnia in people over 55 (as a prolonged-release tablet), sleep-onset difficulties in some children with conditions such as ADHD or autism (started by a specialist), and to reduce jet lag when crossing time zones. Unlike traditional sleeping tablets, it works with the body’s clock rather than sedating the brain, and it is not addictive.
How it works
Melatonin acts on receptors in the brain’s "master clock" (the suprachiasmatic nucleus) that govern the sleep–wake cycle. By topping up the natural evening rise in melatonin — which often declines with age or is disrupted by shift work, jet lag or certain conditions — it reinforces the signal that it is time to sleep, helping people fall asleep and shifting the body clock. It is this clock-setting action, rather than a heavy sedative effect, that makes it useful for particular sleep problems.
What it treats
Conditions Melatonin is used for
Practical use
How to take Melatonin
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it at a consistent time before bed (prolonged-release tablets are usually swallowed whole with or after food).
- For jet lag, take it close to the local bedtime at your destination, for a few days, as advised.
- Use it alongside good sleep habits — regular routine, a dark, cool room, and limiting screens and caffeine in the evening.
- Avoid alcohol and other sedating medicines with it, and take care with driving if it makes you drowsy.
- For children, follow the specialist’s plan and use the child-specific preparation.
Weighing it up
Advantages & disadvantages of Melatonin
Advantages
- Works with the body’s clock; non-addictive and generally well tolerated.
- Useful where traditional sleeping tablets are unsuitable, including in older adults and some children.
- Helpful for jet lag and body-clock (circadian) sleep problems.
Disadvantages
- Less immediately sedating than traditional sleeping tablets — timing is important.
- Can cause daytime drowsiness or headache in some people.
- Does not address the underlying causes of poor sleep.
Practical use
Good to know
Timing matters more with melatonin than with a sedative: it is usually taken at a consistent time in the evening, and prolonged-release forms are designed to mimic the body’s natural overnight release. For older adults it is generally used short-term. For children, it is a specialist decision, often after sleep-behaviour ("sleep hygiene") measures have been tried, and the child-specific forms are used. For jet lag, it is taken close to the target bedtime at the destination. It can cause daytime drowsiness or headache in some people, and it is not a cure for the underlying causes of poor sleep — attention to routine and sleep habits remains important.
Who should not take it / use with caution
- People with a known sensitivity to it, and used with care in autoimmune conditions and significant liver impairment.
- Care alongside other sedating medicines and in people who need to drive or operate machinery if it causes drowsiness.
- Pregnancy and breastfeeding — generally avoided unless advised.
Monitoring
- Usually none for short-term use
- Review of ongoing need and effect on sleep
- In children, specialist review of benefit and behaviour
Side effects
- Usually well tolerated; some people get headache, daytime sleepiness or dizziness.
- Occasionally vivid dreams, irritability or stomach upset.
- It is not associated with the dependence seen with traditional sleeping tablets.
Key interactions
- Alcohol and other sedating medicines add to drowsiness (and alcohol reduces melatonin’s effect on sleep).
- Fluvoxamine and some other medicines raise melatonin levels; certain medicines and smoking lower them.
- Care alongside medicines that affect blood clotting or blood sugar, and with some epilepsy medicines.
Available as: Prolonged-release tablets, immediate-release tablets, and child-friendly forms (mini-tablets/liquid) for specialist use.
Answers
Melatonin: frequently asked questions
Is melatonin addictive?
No — melatonin is not associated with the dependence or tolerance seen with traditional sleeping tablets such as benzodiazepines or Z-drugs. It works by reinforcing the body’s natural sleep signal rather than sedating the brain, and it can usually be stopped without withdrawal effects.
When should I take melatonin?
At a consistent time in the evening before your intended bedtime — prolonged-release forms are designed to mimic the body’s natural overnight release. For jet lag, take it close to the local bedtime at your destination. Consistent timing, alongside good sleep habits, is what makes it work.
Can children take melatonin?
Yes, but it is a specialist decision — it is used for sleep-onset problems in some children, particularly those with conditions such as ADHD or autism, usually after sleep-behaviour measures have been tried. Child-specific preparations are used, and the dose and timing are guided by the specialist.
Will melatonin knock me out like a sleeping pill?
Not usually — it is gentler and works by nudging your body clock rather than forcing sleep, so timing and routine matter more. This makes it useful for certain sleep problems, but if you expect a strong sedative effect you may be disappointed; discuss the best approach for your sleep with your doctor or pharmacist.
The wider class
About Melatonin (sleep medicine)
Melatonin belongs to the melatonin (sleep medicine) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF: Melatonin.
- electronic Medicines Compendium (SmPC): Circadin; Slenyto.
- NICE CKS: Insomnia.
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