How long should my child stay on melatonin, and how do we stop?

Parents often ask me how long their child will need melatonin. There is no set answer. This post explains how reviews and trial breaks usually work in the UK National Health Service (NHS), and what the research says about stopping.

For the different products, see Melatonin for autistic children: the types, and what is in them. For how melatonin is prescribed, see Getting melatonin on the NHS for an autistic child.

Melatonin treats the sleep problem. It does not treat autism.

Why review matters

Sleep changes as children grow. A child who needed melatonin at 6 may sleep well without it at 9. The only way to know is to check.

There is also a safety reason. We have good data for up to 2 years of use. Beyond that, the data are more limited. The Thames Valley protocol notes "the limited amount of rigorous safety data for more than two years of continued use." So doctors check growth and puberty at reviews.

The evidence on puberty is reassuring but small. It does not prove melatonin is safe long term, and it does not prove harm.

What the guidance says

The National Institute for Health and Care Excellence (NICE) writes the guidelines NHS doctors follow. Its autism guideline for under-19s is CG170.

CG170 says melatonin should be used alongside a sleep plan. It also says doctors should "regularly review to evaluate the ongoing need" for it. NICE does not set a length of treatment, a break schedule or a way to stop.

Slenyto is a slow-release melatonin licensed for autistic children. Its summary of product characteristics (SPC) is the official prescribing information. The SPC says:

• the doctor should check the effect after at least 3 months, and consider stopping if it is not helping
• your child should be reviewed at least every 6 months.

No source sets a maximum length of treatment. Views differ. Thames Valley says melatonin "should usually only be a short-term intervention". Norfolk and Waveney says treatment "may need to be long term".

Trial breaks

A trial break means stopping melatonin for a short time to see if your child still needs it. There is no national UK rule on when to do this. Local NHS areas set their own schedules. Here are some examples:

• Thames Valley: a break at least once a year, often in the 2 weeks before the yearly review.
• Norfolk and Waveney and Humber and North Yorkshire: a break 3 months after starting, then every 6 months.

Your child's doctor will tell you what applies in your area.

What happens

A break usually lasts 2 weeks. Pick a quiet time, such as the school holidays. Avoid weeks with exams, a house move or other big changes.

Agree the break with your child's doctor first. Do not start one on your own.

What to watch

Watch how long it takes your child to fall asleep, how often they wake and when they wake in the morning. Also watch their mood and behaviour in the day.

It is normal for sleep to slip a little. In the Slenyto trial, 80 children took Slenyto for up to 2 years and then had 2 weeks on a dummy tablet (placebo). Sleep got a bit worse in those 2 weeks, but it stayed better than before treatment. There was no rebound, meaning sleep did not become worse than it had been at the start (Malow 2021). This study was funded by the company that makes Slenyto. It applies to Slenyto only, not to every melatonin product.

Keep a sleep diary

Write down bedtime, the time your child fell asleep, night waking and waking time. Start a few days before the break if you can. Bring the diary to the review. It helps the doctor decide much more than memory does.

After the break

If sleep stays fine, your child can stay off melatonin. If sleep clearly gets worse, it can be restarted. Your doctor will tell you what dose to restart, because areas differ on this.

Stopping

There is no study comparing a slow reduction (tapering) with stopping at once. A 2026 review found little research on the best way to stop, and said no evidence-based guidance on this can be given yet. So please agree the plan to stop with the doctor who prescribes melatonin.

One local view: the Thames Valley protocol says, "There is no need to taper the dose down." It says this about stopping when melatonin has not helped.

Some areas plan a trial off melatonin before adult care. Thames Valley expects a planned trial off melatonin in the 6 to 12 months before a young person's 18th birthday.

In a Dutch study of young people with trouble falling asleep (not a study of autistic children), those who had started melatonin before puberty were asked how they slept about 10 years later. About 3 in 4 slept normally without medicine (Zwart 2018). Under half replied, and the answers were self-reported. So this figure may not apply to autistic children.

When to talk to your doctor

Talk to your child's doctor:

• before you start a trial break or stop melatonin
• if melatonin no longer seems to help
• if sleep is clearly worse after a break
• if you have questions about growth or puberty
• if your child is approaching 17 and you want to plan for adult care.

References

1. National Institute for Health and Care Excellence. Autism spectrum disorder in under 19s: support and management (CG170), recommendation 1.7.7. Published 2013, updated 2021. https://www.nice.org.uk/guidance/cg170/chapter/Recommendations
2. European Medicines Agency. Slenyto: EMA product information (summary of product characteristics, sections 4.2 and 5.1). https://www.ema.europa.eu/en/documents/product-information/slenyto-epar-product-information_en.pdf
3. Malow BA, et al. Sleep, Growth, and Puberty After 2 Years of Prolonged-Release Melatonin in Children With Autism Spectrum Disorder. J Am Acad Child Adolesc Psychiatry 2021;60(2):252-261.e3. https://doi.org/10.1016/j.jaac.2019.12.007 (funded by the manufacturer)
4. Zwart TC, et al. Long-Term Melatonin Therapy for Adolescents and Young Adults with Chronic Sleep Onset Insomnia and Late Melatonin Onset. Healthcare (Basel) 2018;6(1):23. https://doi.org/10.3390/healthcare6010023
5. Baens M, Danckaerts M. [The importance of a DLMO-measurement when starting and stopping melatonin in minors] (in Dutch). Tijdschr Psychiatr 2026;68(2):70-74. https://pubmed.ncbi.nlm.nih.gov/41733025/
6. NHS Thames Valley Integrated Care Board. Melatonin shared care protocol, v4.1, updated July 2024. https://thamesvalley.icb.nhs.uk/media/4960/melatonin-shared-care-protocol.pdf
7. NHS Norfolk and Waveney. Melatonin for sleep disorders in children: shared care, v8, May 2025. https://nwknowledgenow.nhs.uk/wp-content/uploads/2025/06/Melatonin-for-Sleep-Disorders-in-Children-v8-May-2025.pdf
8. NHS Humber and North Yorkshire. Melatonin prescribing guideline for children and young people, v1.0, approved 3 September 2025. https://humberandnorthyorkshire.org.uk/wp-content/uploads/2025/09/2025-09-HNY-Melatonin-prescribing-guideline-v1.0-FINAL-children-and-young-people.pdf