In 30 seconds
- Melatonin is the hormone your body releases when it gets dark and that sets your sleep clock.
- A meta-analysis of 19 studies found that you fall asleep about 7 minutes sooner and sleep about 8 minutes longer, with an effect that holds with continued use.
- The EU authorises this claim for foods that provide 1 mg shortly before bedtime: “Melatonin contributes to the reduction of time taken to fall asleep.”
- In Spain, supplements may contain less than 2 mg a day. In older adults, 0.3 mg worked better than about 3 mg.
Melatonin is probably the most widely known sleep supplement. It is the signal that tells your body it is night-time, which is why it works best as part of a routine. This is what the studies and the legislation say.
What it is and what it does
It is a hormone made by the pineal gland when it gets dark. It does not “knock you out”: it tells your body that it is night-time and helps synchronise your internal clock with the cycle of light and dark. That is why screen light at night and irregular schedules disrupt it.
Level of evidence by outcome
| Outcome | Evidence | What the data show |
|---|---|---|
| Time taken to fall asleep | Moderate | About 7 minutes less in 19 studies with 1,683 people. |
| Total sleep time | Low | About 8 minutes more; the effect is seen in what people perceive, not in measurements. |
| Sleep quality | Moderate | A small but significant improvement. |
| Jet lag | High | Authorised EU claim with 0.5 mg or more. |
The rating is our own, based on the number of studies, their quality and the consistency of the results.
The key studies
| Study | Type | Sample | Outcome |
|---|---|---|---|
| Ferracioli-Oda et al., 2013 | Meta-analysis | 19 studies, 1,683 people | 7 minutes less to fall asleep, 8 minutes more sleep and better perceived quality. The effects are not lost with continued use. 1 |
| Zhdanova et al., 2001 | Placebo-controlled trial | Adults over 50 | 0.3 mg restored sleep efficiency in those who slept poorly. About 3 mg worked less well and raised melatonin during the day. 2 |
| Erland and Saxena, 2017 | Product analysis | 31 supplements | The actual melatonin ranged from 83% less to 478% more than the label stated. 3 |
| Regulation (EU) No 432/2012 | Legislation | Authorised claims | “Melatonin contributes to the reduction of time taken to fall asleep.” At 1 mg shortly before bedtime. “Melatonin contributes to the alleviation of subjective feelings of jet lag.” At 0.5 mg or more. 4 |
An effect that holds
The Ferracioli-Oda meta-analysis brought together 19 studies with 1,683 people with sleep problems. With melatonin, they fell asleep about 7 minutes sooner, slept about 8 minutes longer and rated their sleep more highly 1.
And two findings are in its favour: the effects do not disappear with continued use, and the longer studies with slightly higher doses showed more sleep time 1. The increase in sleep time was seen in what people perceived, not in objective measurements.
Amounts of melatonin
The figures from the studies and the legislation
A higher dose is not always better
In a study with adults over 50, 0.3 mg restored sleep efficiency in those who slept poorly. A dose of about 3 mg worked less well and left blood melatonin high during the day, which can cause a hangover-like feeling 2.
What the legislation authorises
This is the EU's general information on melatonin as an ingredient. It authorises two claims, and each one can only be used by a food that provides the amount it requires 4:
- Falling asleep: “Melatonin contributes to the reduction of time taken to fall asleep.” It requires 1 mg taken close to bedtime.
- Jet lag: “Melatonin contributes to the alleviation of subjective feelings of jet lag.” It requires 0.5 mg or more taken close to bedtime on the first day of travel and on the first few days after arrival.
A varied and balanced diet and a healthy lifestyle are important.
In Spain, food supplements may contain less than 2 mg a day; above that, it is considered a medicine 5.
Check the label
What was found when 31 supplements were analysed
Check the label
In an analysis of 31 melatonin supplements, more than 70% did not match what their label stated: the actual amount ranged from 83% less to 478% more 3. That is why it is worth choosing a brand that tells you where and how what you buy is made.
Frequently asked questions
What is melatonin?
A hormone made by the pineal gland when it gets dark. It tells your body that it is night-time and helps synchronise your internal clock with the cycle of light and dark.
How much melatonin can you take in Spain?
In food supplements, less than 2 mg a day. Above that, Spain's medicines agency considers it a medicine.
Is more melatonin better?
Not necessarily. In adults over 50 who slept poorly, 0.3 mg worked better than about 3 mg, which also left melatonin levels high during the day.
Is melatonin habit-forming?
The reference meta-analysis found that its effects are not lost with continued use. Even so, if you have persistent sleep problems, the right step is to talk to your doctor.
Who should not take melatonin?
Check with your doctor if you are pregnant or breastfeeding, take medication or have a medical condition. And do not combine it with alcohol or drive if it makes you drowsy.
Sources
- Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013;8(5):e63773. View publication
- Zhdanova IV, Wurtman RJ, Regan MM, Taylor JA, Shi JP, Leclair OU. Melatonin treatment for age-related insomnia. J Clin Endocrinol Metab. 2001;86(10):4727-4730. View publication
- Erland LAE, 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. View publication
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. View publication
- AESAN. Use of melatonin in food supplements. Note of 4 July 2013, reproduced by the Basque Government. View publication
Information based on published studies. It does not replace the advice of a doctor or registered dietitian. The results describe what was measured in each study, not the properties of any specific product.
