In the UK, 10mg is five times the NHS dose for short-term adult insomnia: one 2mg slow-release tablet, for up to 13 weeks. It is the NHS maximum, five tablets once daily, only for longer-term sleep problems a specialist prescribes. Melatonin is prescription-only here.
This is an evergreen explainer; the US pages ranking for this query describe a shelf the UK lacks. This desk read the NHS dosing page, an MHRA press release and the emc’s melatonin listing on 4 October 2026.
Is 10mg melatonin too much in the UK? Every ceiling by use
| Use | Usual starting dose | Ceiling | Source |
|---|---|---|---|
| Adult short-term insomnia | One 2mg slow-release tablet | 13 weeks, longer on specialist advice | NHS |
| Adult longer-term, specialist | One 2mg slow-release tablet | 10mg (5 tablets) once daily | NHS |
| Children and teenagers, specialist | One 2mg slow-release tablet | 10mg once daily | NHS |
| Children, licensed use | 1mg | 5mg a day | MHRA |
| Adult jet lag | One 3mg tablet | 6mg, 5 days, 16 courses a year | NHS |
The children’s rows disagree: the NHS allows up to 10mg once daily, the MHRA “a maximum of 5mg per day”. Jet lag has its own explainer.
Can you get 10mg melatonin in the UK?
Not as one tablet, in what this desk read. The emc melatonin listings in the window read ran from 1mg to 5mg (Adaflex 1mg to 5mg, Circadin 2mg, Ceyesto 3mg); none was 10mg, and the listing may run on past them.
Online gummies are another matter: in August 2025 the MHRA had a children’s food-supplement gummy removed from sale over undeclared melatonin, saying such a product “must be regulated as a medicine”. See whether you can buy melatonin over the counter and whether it is a supplement or a medicine.
Frequently asked questions
Is it safe to take 10mg of melatonin?
It depends on who prescribed it and why. The NHS sets 10mg once daily as the maximum for specialist, longer-term use in adults, children and teenagers; its short-term adult insomnia dose is 2mg. This desk makes no safety judgement beyond those figures.
What happens when you take too much melatonin?
The MHRA, warning about a children’s gummy, says too much melatonin can cause drowsiness, headache, dizziness and nausea, that lasting harm is not expected, and that the body typically clears it within 12 hours. The NHS says one or two extra tablets are unlikely to harm you; contact 111 if you took more than prescribed and feel unwell.
Is it safe to use a high dose melatonin (10-15mg) daily?
None of the UK pages read sets a dose above 10mg, the NHS maximum for longer-term specialist use, so 15mg sits above every ceiling in the table. The NHS says courses beyond 13 weeks are on a specialist’s advice, and melatonin is prescription-only in the UK.
Nothing here is medical advice; ask a prescriber or pharmacist about your own dose.