You often hear about melatonin, and wonder if taking it as a supplement can help you sleep better ? Here’s my personal opinion, based on the studies I’ve analysed.
♻️ Last updated: November 23, 2025
Written by Nelly Darbois, former physiotherapist and science writer
Summary
What is melatonin?
Melatonin is a hormone naturally produced by our brain in an area called the pineal gland. It tells our body that it’s time to go to sleep.
Its production increases when light levels fall: in the evening, your brain receives fewer light signals, so it releases more melatonin.
On the contrary, light (especially screens) slows down its production.
It also varies according to :
- your sleep rhythm: going to bed late or changing your bedtimes often disrupts its rise;
- age: we produce less as we age;
- certain habits: late coffee, stress or exposure to screens can delay onset.
Why is it reasonable to think that taking melatonin improves sleep?
When you take melatonin by mouth, it passes through your digestive tract and is absorbed into your bloodstream. In about 20-40 minutes, its blood level rises, just as if your brain had released more of it.
Once in the bloodstream, it circulates everywhere and reaches the brain, where it binds to specific receptors. These receptors can trigger the same reactions as natural melatonin: reduced wakefulness, slight drop in internal temperature, and activation of “night mode”.
It’s this direct effect on sleep receptors that explains why a supplement could, in theory, help: it would artificially boost the night-time signal, even if your own production arrives too late, is blocked by light or is simply too low.
What do studies say about the effect of melatonin on better sleep?
There are numerous studies published every year on the effects of melatonin on sleep:
One of the most recent syntheses is that of Cruz-Sanabria et al. in 2024.
They started from the observation that studies on melatonin did not all reach the same conclusions: some found a clear effect on sleep, others almost nothing. Why was this? Probably because people didn’t take it at the same time or in the same dose.
They carried out a major analysis of 26 studies published between 1987 and 2020, involving a total of almost 1,700 people: some taking melatonin, others not. They looked at two things:
- how long it took people to fall asleep,
- how long they slept in total.
Here’s what they found:
👉 1. Melatonin seems to help… but not just any way.
The higher the dose, the more noticeable the effect – up to around 4 mg. Beyond that, the benefits no longer seem to increase.
👉 2. Timing is even more important than dose.
Melatonin would be more effective if taken about 3 hours before the time you want to sleep, rather than 30 minutes before as is often recommended.
👉 3. People with insomnia react more.
The effects are clearer in people with real sleep problems than in healthy volunteers.
Another team in 2025 (Iyer et al.) identified 57 systematic reviews, grouping 227 meta-analyses. Only 8.8% of them complied with all the strict methodological rules (published protocol, double-checking of data, bias analysis, etc.).
Among the 215 meta-analyses that compared melatonin to placebo :
- 80.9% found melatonin better,
- 7.9% thought the placebo did better,
- 11.2% couldn’t decide.
Each scientific team used its own tools: some measured the time it took to fall asleep, others nocturnal awakenings, still others the sensation of restful sleep… The result: it was difficult to merge everything neatly.
There are also interesting case-by-case studies looking at the effects of melatonin when you also have other health problems, such as Parkinson’s disease, or when you’re hospitalized in intensive care.
What form should it take, and in what quantities, if you want to try it out?
Here are the different forms available.
- Classic tablets: the most common form, gradually absorbed.
- Sublingual tablets: melt under the tongue for faster, more predictable absorption.
- Capsules: same effects as tablets.
- Drops: adjust dose to the nearest milligram.
- Mouth sprays: fast-acting, but sometimes less precise dosage.
- Herbal tea: dosing is much more complicated to master.
If you want to test precisely, I recommend :
- Sublingual tablets: rapid absorption, more regular effect;
- or drops: to fine-tune the dose.
The most recommended dose for testing is 0.5 mg to 1 mg (and up to 4 mg), 1 to 3 hours before bedtime, for an adult.
You can buy them in chemists, parapharmacists or online(see Amazon; affiliate link).
Are there any possible side effects from taking melatonin?
Melatonin supplementation in people with autoimmune diseases, such as rheumatoid arthritis, or after organ transplants, should be discussed, as it can stimulate the immune system.
Melatonin supplements are rarely associated with cases ofangioedema (which may be due more to the unregulated excipients present in some formulations, triggering allergic reactions.
Source: Savage 2025
My personal opinion on taking melatonin for sleep
Like many people, I’ve always had trouble falling asleep, or getting back to sleep after waking up at 3am. Although it doesn’t necessarily get worse over the years, these phases can be distressing. That’s what prompted me to wonder whether taking melatonin might be a reasonable solution.
So I looked at the studies. And the further I got, the more I realized that, for me, given theuncertainty about the effects of supplements, I’d rather not take any for the time being. Not even “to test”. I prefer to keep this option on the back burner, in case I ever experience a really difficult period in terms of sleep.
Today, I realize that with simple habits :
- a less stressful life,
- regular working hours (even at weekends),
- reading when I can’t sleep,
- and, above all, put things into perspective (“if I’m tired tomorrow, it’s no big deal, my body can handle it”),
my sleep has stabilized.
So, as long as these routines work, I find it more logical to stick with them than to try a supplement whose effects remain uncertain. But I keep the idea in the back of my mind: if one day I’m really at the end of my tether, I know that melatonin exists and that I could try it then.
***
That’s all I wanted to say on the subject! Any questions or comments? See you in comments!
You may also be interested in these articles:
SOURCES
Savage RA, Zafar N, Yohannan S, et al. Melatonin. [Updated 2024 Feb 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534823/
Cruz-Sanabria F, Bruno S, Crippa A, Frumento P, Scarselli M, Skene DJ, Faraguna U. Optimizing the Time and Dose of Melatonin as a Sleep-Promoting Drug: A Systematic Review of Randomized Controlled Trials and Dose-Response Meta-Analysis. J Pineal Res. 2024 Aug;76(5):e12985. doi: 10.1111/jpi.12985. PMID: 38888087.
Iyer S, Monk V, Slater R, Baxter L. Exogenous Melatonin and Sleep Quality: A Scoping Review of Systematic Reviews. J Clin Pharmacol. 2025 Sep 27. doi: 10.1002/jcph.70115. Epub ahead of print. PMID: 41014554.
Written by Nelly Darbois
I enjoy writing articles that answer your questions, drawing on my experience as a physiotherapist and scientific writer, as well as extensive research in international scientific literature.
I live in the French Alps☀️🏔️, where I enjoy the simple pleasures of life (+ I’m a Wikipedia consultant and the founder of Wikiconsult).