What We Still Don't Know About Melatonin
Melatonin has become one of those unremarked-on fixtures of family life that nobody quite remembers agreeing to. I understand the pull of it completely — there is a particular exhaustion that sets in at half past nine, with a child still wide awake and a school morning already visible on the other side of a bad night, that makes any promise of calm look like common sense.
In the UK, prescriptions for children have more than tripled in under a decade — from 33,926 in the first quarter of 2015 to 117,093 in the same quarter of 2024, according to NHS data obtained by The Pharmaceutical Journal. In America, there's no prescription pad involved at all. It sits on the shelf beside the vitamin C and the fish oil, sold as a supplement rather than a medicine, and nearly one in five school-aged children now take it most months — a figure that doubled between 2017 and 2020.
Two very different systems, arriving at the same place: a substance almost nobody thought carefully about has become one of the most-used in modern childhood.
Two systems, the same shrug
In the UK, the reasons are more forgivable than they first sound. Melatonin here requires a paediatrician's prescription, so its rise isn't really a story about casual parental reaching. It has settled into a kind of pacifier for an overstretched system — prescribed even when the benefit is limited, because the alternatives barely exist. Cognitive behavioural therapy for insomnia is underdeveloped for children, and waiting lists for psychological support stretch on for months a tired family doesn't have. A single hospital audit found that the most common reason for prescribing was autism spectrum disorder, and that four in ten children had no diagnosis yet at all — they were simply waiting, while sleepless, for an assessment that hadn't come. The tablet, in other words, is often standing in for a system that hasn't arrived.
In America, the story is closer to what most of us picture when we hear “melatonin gummy”: something reached for casually, at bedtime, the way you'd reach for a plaster. It's regulated as a supplement rather than a drug, so it answers to almost none of the scrutiny we'd expect of something given to a child nightly.
What the data doesn't show yet
A commentary from a sleep researcher at the University of Miami, responding to a study just published in JAMA Network Open, looked at children's REM sleep — the stage where a developing brain sorts memory and regulates emotion — comparing those who took melatonin with those who didn't, using overnight recordings rather than parental guesswork. The early difference didn't hold up once other factors were accounted for; across the board, there was no meaningful gap. This is not proof that melatonin harms a child's brain. It is proof of something quieter and more uncomfortable: that a study this basic — simply watching, properly, what melatonin does to a child's sleep — has taken this long to happen, despite millions of children already taking it every night.
Here's the part that neither the American supplement aisle nor the NHS repeat prescription quite conveys: melatonin is, properly understood, not a sedative but a chronobiotic — a chemical signal that helps set the body's internal clock, whose effect depends on dose, timing, formulation and the child taking it. Long-term safety data remain thin on both sides of the Atlantic. Trials in typically developing children are almost nonexistent; most of what we know comes from children with neurodevelopmental conditions, a very different starting point. In America, a separate review found melatonin is now the leading cause of accidental medication overdose among young children turning up in emergency rooms — not because the hormone itself is especially dangerous in a single dose, but because a bottle marketed like sweets, kept within reach of small hands, invites exactly the kind of accident a locked medicine cabinet was built to prevent.
The case for it
None of this is an argument against melatonin used well. A child with a genuine circadian rhythm disorder, prescribed a specific dose for a specific reason and reviewed by someone qualified to say so, is a world away from a nightly half-tablet reached for out of habit because bedtime has become a battle nobody has the energy to fight properly. The distinction is the whole point. Sleep problems are not one problem with one solution — they're a symptom with a few possible causes, from inconsistent bedtimes to too much stimulation before sleep to anxiety. Melatonin treats none of those causes. It simply nudges the clock.
Before the Bottle
- Has anything changed recently — school, screens, a new worry — that might be behind the wakefulness, rather than the wakefulness itself being the problem?
- Has the bedtime routine actually been tested and held to consistently for two full weeks, or has melatonin arrived before that chance was properly given?
- Is this occasional — a long-haul flight, a genuinely rough patch — or has it quietly become nightly without a decision being made?
- If it has become a habit, has a doctor reviewed it recently, or is it simply being refilled?
Where I've landed
What I'd want any mother to know, prescription pad or supplement aisle, isn't that she's done something wrong. It's that “nobody's proven this is harmful” and “this is proven safe” are two very different sentences, and neither a pharmacy label nor a repeat prescription will tell you which one you're actually getting. Keep the bottle out of small hands regardless. If it becomes nightly rather than occasional, treat that the way you would any medicine that's become a habit — worth a proper conversation with whoever prescribed it, not just a shrug and a refill.
A Note from Mrs H
I'm not precious about a helping hand at bedtime — heaven knows every mother I know has reached for one on a bad night. What strikes me most about the UK and US pictures side by side is that neither is really about melatonin at all. One is about a system too stretched to offer anything else. The other is about a shelf too casual to demand anything better. Both are worth noticing before the tablet becomes the whole answer.
— Mrs H