Melatonin for autistic children: the types, and what is in them

Melatonin is the medicine I am asked about most often in clinic. Parents often find that the melatonin their child is given changes from one prescription to the next. There are several products. They differ in who they are licensed for, how they are taken, and what else is in them.

This post covers the melatonin medicines prescribed in the UK. In the UK melatonin is a prescription-only medicine. At the end there is a short section on gummies and melatonin bought abroad.

If your child cannot swallow tablets, they can learn. KidzMedz teaches children over five a six-step method: KidzMedz Cymru (Cardiff and Vale University Health Board).

Who each melatonin is licensed for

Slenyto is the only melatonin licensed for autistic children. The other children's tablets and liquids are licensed for sleep problems in children with ADHD (attention deficit hyperactivity disorder) aged 6 to 17. Circadin is licensed only for adults aged 55 and over. Doctors often prescribe these other products for autistic children. This is called off-label prescribing. Off-label prescribing is common and allowed. Your doctor can explain why they chose this medicine.

What does licensed mean?

Licensed. In the UK the MHRA (Medicines and Healthcare products Regulatory Agency) grants each medicine a licence. The licence says which condition the medicine is for, which age group, and which form, such as a tablet or a liquid. To get a licence, the company has to run clinical trials showing the medicine works and is safe. Trials are almost always done in adults first. Many medicines have not been fully tested in children.

Off-label. This means using a licensed medicine in a different way from its licence. One example is a different age group or a different condition. It is also called off-licence use.

Unlicensed. This means a medicine with no UK licence. Examples are "specials", made up by a pharmacy or a specialist manufacturer, and medicines imported from another country where they are licensed.

Off-label or unlicensed use does not by itself mean a medicine is unsafe. It means the company does not hold a licence for that use.

Off-label prescribing is common and allowed. Your doctor can explain why they chose this medicine.

Sources: MHRA, Drug Safety Update on off-label or unlicensed use of medicines; Medicines for Children leaflet on unlicensed medicines.

The products

Slow-release tablets

Slenyto (1 mg and 5 mg prolonged-release tablets)

• Licensed for: sleep problems (insomnia) in children and young people aged 2 to 18 with autism and/or neurogenetic disorders, when sleep routines alone have not worked. Also licensed for insomnia in children aged 6 to 17 with ADHD.
• How it is taken: small tablets, 3 mm across. They release melatonin slowly through the night.
• Can it be crushed? Yes, but it then stops releasing slowly. See Crushing below.
• Lactose: yes. 8.32 mg per 1 mg tablet; 8.86 mg per 5 mg tablet.

Circadin (2 mg prolonged-release tablet)

• Licensed for: short-term treatment of insomnia in adults aged 55 and over only. Use in children is off-label.
• How it is taken: swallowed whole.
• Can it be crushed? Yes, but it then stops releasing slowly. See Crushing below.
• Lactose: yes. 80 mg per tablet.

Immediate-release tablets

Adaflex (1 mg to 5 mg tablets)

• Licensed for: insomnia in children aged 6 to 17 with ADHD, and jet lag in adults.
• How it is taken: by mouth.
• Can it be crushed? Yes. The tablet can be crushed and mixed with water just before it is taken.
• Lactose: contains no lactose. No excipients with known effect are listed.

Mellozzan (2 mg, 3 mg and 5 mg tablets)

• Licensed for: insomnia in children aged 6 to 17 with ADHD, and jet lag in adults.
• How it is taken: by mouth.
• Can it be crushed? Yes. The tablets can be crushed and mixed with water just before they are taken.
• Lactose: contains no lactose. No excipients with known effect are listed.

Ceyesto (3 mg tablets)

• Licensed for: insomnia in children aged 6 to 17 with ADHD, and jet lag in adults.
• How it is taken: swallowed with a glass of water. Food at around the same time is not expected to change how well it works.
• Can it be crushed? The product information does not say whether it can be crushed. Ask your pharmacist.
• Lactose: contains no lactose. No excipients with known effect are listed.

Liquids

The liquids differ a lot in what else they contain, so check the exact product. All are 1 mg per ml unless stated. They are given with the oral syringe that comes with the bottle.

Ceyesto 1 mg/ml oral solution

• Licensed for: insomnia in children aged 6 to 17 with ADHD, and delayed sleep wake phase disorder (body clock set late) in people aged 6 to 25.
• How it is taken: by mouth, measured with the 5 ml oral syringe provided.
• Lactose: contains no lactose.

Melatonin 1 mg/ml oral solution (with sorbitol)

• Licensed for: insomnia in children aged 6 to 17 with ADHD, and jet lag in adults. It is not licensed for delayed sleep wake phase disorder.
• How it is taken: by mouth. Food can increase how much melatonin is absorbed.
• Lactose: contains no lactose.

Sleplag (1 mg/ml and 2 mg/ml oral solution)

• Licensed for: insomnia in children aged 6 to 17 with ADHD, and delayed sleep wake phase disorder in people aged 6 to 25.
• How it is taken: by mouth, drawn up with the oral syringe provided. Food can increase how much melatonin is absorbed.
• Lactose: contains no lactose.

Melatonin 1 mg/ml oral solution (with parabens)

• Licensed for: insomnia in children aged 6 to 17 with ADHD, and delayed sleep wake phase disorder in people aged 6 to 25.
• How it is taken: by mouth, measured with the 10 ml oral syringe provided.
• Lactose: contains no lactose.

What else is in the tablets and liquids

Tap a product to see what else it contains.

Slenyto

• Licence: Autism and/or neurogenetic disorders; ADHD
• Age: 2–18; 6–17
• Form: Slow-release tablet
• Lactose: 8.32 mg / 8.86 mg
• Propylene glycol: No
• Other ingredients: –
• Can it be crushed? See Crushing below

Circadin

• Licence: Insomnia, adults
• Age: 55+
• Form: Slow-release tablet
• Lactose: 80 mg
• Propylene glycol: No
• Other ingredients: –
• Can it be crushed? See Crushing below

Adaflex

• Licence: ADHD insomnia
• Age: 6–17
• Form: Tablet
• Lactose: None
• Propylene glycol: No
• Other ingredients: None with known effect
• Can it be crushed? Yes, in water

Mellozzan

• Licence: ADHD insomnia
• Age: 6–17
• Form: Tablet
• Lactose: None
• Propylene glycol: No
• Other ingredients: None with known effect
• Can it be crushed? Yes, in water

Ceyesto 3 mg

• Licence: ADHD insomnia
• Age: 6–17
• Form: Tablet
• Lactose: None
• Propylene glycol: No
• Other ingredients: None with known effect
• Can it be crushed? Not stated; ask your pharmacist

Ceyesto 1 mg/ml

• Licence: ADHD insomnia; delayed sleep phase
• Age: 6–17; 6–25
• Form: Liquid
• Lactose: None
• Propylene glycol: 52 mg/ml
• Other ingredients: Benzyl alcohol, sucralose
• Can it be crushed? –

Melatonin 1 mg/ml (sorbitol)

• Licence: ADHD insomnia; jet lag in adults
• Age: 6–17; adults
• Form: Liquid
• Lactose: None
• Propylene glycol: 150.5 mg/ml
• Other ingredients: Sorbitol, sucralose
• Can it be crushed? –

Sleplag

• Licence: ADHD insomnia; delayed sleep phase
• Age: 6–17; 6–25
• Form: Liquid
• Lactose: None
• Propylene glycol: 34.85 mg/ml
• Other ingredients: Glycerol
• Can it be crushed? –

Melatonin 1 mg/ml (parabens)

• Licence: ADHD insomnia; delayed sleep phase
• Age: 6–17; 6–25
• Form: Liquid
• Lactose: None
• Propylene glycol: None listed
• Other ingredients: Methyl parahydroxybenzoate, potassium sorbate, glycerol
• Can it be crushed? –

European safety limits for other ingredients

The European Medicines Agency (EMA) sets warning levels for some ingredients in medicines.

• Propylene glycol keeps the melatonin dissolved. Young children clear it slowly, so it can build up. The warning level is 50 mg per kg of body weight a day from 4 weeks to under 5 years, and 1 mg per kg a day under 4 weeks old. For example, a 15 kg child reaches 750 mg a day with 5 ml of the liquid that contains 150.5 mg/ml. 3 ml of that liquid gives 450 mg, which is below the limit.
• Benzyl alcohol is a preservative. It must not be given to newborn babies. Children under 3 should not take it for more than a week unless their doctor advises it.
• Sorbitol is a sweetener. Children with hereditary fructose intolerance, a rare inherited condition, should not take it. Large amounts can cause stomach upset.
• Parabens are preservatives. They may cause allergic reactions, which can be delayed.

If your child is under 5 or takes a high dose of a liquid, ask your pharmacist whether a liquid with less propylene glycol would suit them better. Also tell them about other liquid medicines your child takes, because the amounts add up.

Why switching melatonin can change sleep

Parents often tell me their child's sleep changed when the melatonin changed. The products are not the same, so this can happen even when the dose looks the same.

Now and again there are supply problems. A family may then have to switch to a different product, or from a liquid to tablets, at short notice. Here is what might change.

Slow or quick release. Slenyto and Circadin release melatonin slowly through the night. The other tablets and the liquids are quick-release. A quick-release product often still helps a child fall asleep, but it may wear off, and some children then wake in the night. Switching the other way, from a liquid or quick-release tablet to Slenyto, can make settling a little slower at first, while sleep through the night may improve.

Crushing. Any melatonin tablet can be crushed, including Slenyto and Circadin. The pack says not to crush the slow-release tablets. That is because crushing stops the slow release, not because it is unsafe. A crushed slow-release tablet works like a quick-release one: it can help your child fall asleep, but it may not last the night. Crushing these tablets is outside their licence, so check with your doctor or pharmacist first. To crush a tablet, use a tablet crusher or two metal spoons. Mix the powder into 15 to 30 ml of water, orange juice or milk, or into a little yoghurt. Give it straight away. Rinse the crusher or spoon with a little water and give that too, so the whole dose is taken. If you want to keep the slow release, the whole tablet can be put in yoghurt, orange juice or ice cream to help it go down.

Mixing medicine into food: with your child's knowledge, or hidden

Mixing a medicine into food or a drink to make it easier to take is fine, as long as your child knows it is there. Ask your pharmacist first which foods are suitable. Hiding a medicine so your child does not know is different. This is called covert medication. It is only allowed when a child cannot understand the decision, the medicine is essential, and the care team has agreed a plan that is reviewed regularly. A child under 16 who understands the treatment well enough (called "Gillick competent") can make their own decision. From 16, young people are assumed to be able to decide for themselves unless they are assessed as unable to. Medicine must never be hidden from a child or young person who can decide. If your child refuses a medicine, talk to their doctor or pharmacist.

Liquid to tablet, or tablet to liquid. Tablets are measured in mg per tablet. Liquids are measured in mg per ml. Most liquids are 1 mg per ml, but Sleplag also comes as 2 mg per ml. Each liquid comes with its own oral syringe, and they are different sizes. Check the dose in ml for the new product, and use the syringe that came with it.

Food. For some liquids, food can increase how much melatonin is absorbed. Giving it with or without a meal can change how well it works. Try to give it the same way each night.

Other ingredients. The slow-release tablets contain lactose. If your child reacts differently after a switch, check the new product's ingredients and the safety limits above.

If your child's sleep changes after a switch, tell your doctor or pharmacist. Do not change the dose yourself.

What the evidence shows

The main trial of Slenyto included 125 children aged 2 to 17. Almost all were autistic; a few had Smith-Magenis syndrome. Their sleep had not improved with routines alone. Over 13 weeks, compared with placebo (a dummy tablet), children on Slenyto slept about 32 minutes longer each night and fell asleep about 25 minutes faster. They did not wake earlier. Sleepiness in the day was more common. In follow-up to 2 years, growth, weight and puberty stayed within normal ranges. The trial and follow-up were funded by Neurim, the company that makes Slenyto, and the follow-up had no placebo group.

Gummies and melatonin bought abroad

In the UK, melatonin is a prescription-only medicine. Melatonin supplements are not authorised for sale in the UK, and the NHS does not recommend ordering melatonin online. In some countries melatonin is sold in shops as a food supplement, often as gummies. These products are not checked like medicines. A study of 31 Canadian melatonin supplements found the amount of melatonin ranged from 83% less to 478% more than the label said. Some also contained serotonin. In the UK, the MHRA has warned parents about a brand of children's magnesium gummies found to contain 1.5 to 1.7 mg of melatonin per gummy that was not on the label. If you are thinking of using melatonin bought on holiday or online, talk to your doctor first.

References

1. Gringras P, et al. Efficacy and safety of pediatric prolonged-release melatonin for insomnia in children with autism spectrum disorder. J Am Acad Child Adolesc Psychiatry. 2017;56(11):948–957.e4. doi:10.1016/j.jaac.2017.09.414. PMID 29096777.
2. 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. PMID 31982581.
3. Erland LA, Saxena PK. Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content. J Clin Sleep Med. 2017;13(2):275–281. PMID 27855744.
4. MHRA. Off-label or unlicensed use of medicines. Drug Safety Update.
5. NHS. Common questions about melatonin.
6. MHRA. Parents and caregivers advised to stop all use of specific brand of kids' magnesium gummies due to the presence of an undeclared prescription-only medicine.
7. Medicines for Children. Unlicensed medicines (parent leaflet).
8. Summaries of Product Characteristics (electronic medicines compendium, medicines.org.uk/emc), accessed 24 October 2026: Slenyto 10023/10024; Circadin 2809; Adaflex 13628; Mellozzan 101546; Ceyesto tablets 12815; Ceyesto oral solution 15067; Melatonin oral solution 10419 and 15093; Sleplag 100026/100027.
9. West Yorkshire Integrated Care System. Melatonin tablets – advice for crushing. Parent leaflet, October 2022.
10. NICE. Babies, children and young people's experience of healthcare (NG204), recommendation 1.1.3.
11. Mental Welfare Commission for Scotland. Covert medication: good practice guide. 2022.
12. NHS Greater Glasgow and Clyde. Guidance on covert administration of medicines. 2024.
13. European Commission. Annex to the European Commission guideline on 'Excipients in the labelling and package leaflet of medicinal products for human use' (SANTE-2017-11668), Revision 5. European Medicines Agency; 2025.