Melatonin

Melatonin is one of the most misunderstood things sold in a drugstore, and the misunderstanding got there with help from the supplement industry, the…

Sections

1. The four situations where it earns its keep
2. Where the marketing falls apart
3. Timing matters more than dose
4. The supplement industry mess
5. How I think about it
6. Sources

Melatonin might be the most misunderstood thing on a drugstore shelf, and it got that way with a lot of help, from the supplement industry, from the pediatrician’s office, and from your uncle who knows a guy. People swallow it the way they’d swallow Benadryl. Like a sedative. Like something that’s gonna knock them out. That’s just not what it does. Melatonin is your sleep-timing hormone, the stuff your pineal gland (a little gland sitting in the middle of your brain that runs your body clock) drips out in tiny amounts as the evening light dies down, and the message it sends to the rest of your brain is basically: hey, it’s getting to be nighttime, start winding down.

That’s pretty much all it does. It doesn’t knock you out, slow your breathing, or touch the GABA receptors that real sleeping pills grab onto. All it does is tell the master clock in your hypothalamus what time it is. So if your clock is already running on schedule and you’re just lying there because you’re stressed, or you had coffee too late, or your kid was up at 3 in the morning, melatonin isn’t gonna do much for you. But if your clock is truly knocked out of whack, melatonin can be one of the more useful things in the cabinet.

Then there’s the dose on the bottle, which nobody wants to talk about. The 5mg gummy at CVS, the 10mg “extra strength” at Costco, the 12mg sleep stack from whatever Instagram brand your buddy at the gym swears by. Your own pineal gland makes something like 0.1 to 0.3mg at its peak. Megadoses just flood the receptors and cause downregulation, which is a fancy way of saying your own body starts making less melatonin because the receptors are already maxed out, and then you get weird dreams and you’re groggy at 9 in the morning. So with melatonin, more just gets you worse sleep.

One gummy they tested had zero melatonin in it. Just 31mg of CBD.

The four situations where it earns its keep

There are four spots where melatonin pulls its weight, and I’ll go roughly in order of how solid the data is.

First one’s jet lag. You flew from New York to Paris and your body still thinks it’s 6 PM while everyone in Paris is heading to bed. Take a small dose a couple hours before the local bedtime for two or three nights and it helps drag your rhythm forward to match where you are. This is the cleanest evidence we’ve got, it’s the use where you can really feel it working, and honestly it’s pretty much what the stuff was made for.

Second is delayed sleep phase syndrome. That’s the teenager or the twenty-something whose body flat out doesn’t want to sleep until 3 AM and doesn’t want to get up before 11. This is a real circadian setting, not the same as being lazy or being glued to a phone, and a decent slice of people just naturally run that way. A small dose a few hours before the bedtime you’re aiming for, paired with bright light in the morning, can shift the whole rhythm earlier over a few weeks. It’s slow and you’ve gotta stay on top of it, but it works.

Third is shift work, sometimes, for the guys stuck rotating schedules who have to talk their brain into believing 10 AM is bedtime. It’s never a clean fix, because the rest of the world is loud at 10 AM and the sun’s doing the exact wrong thing, but it can take the edge off if you stack it with blackout curtains and a routine you don’t break.

Fourth is REM sleep behavior disorder, and this one’s in a category of its own. RBD is where people physically act out their dreams, so they’re punching and kicking and falling out of bed. It mostly shows up in older men, and it matters way beyond the bruises because it can predict Parkinson’s disease and Lewy body dementia coming down the road (Postuma et al. 2019), which is the kind of thing that wakes you up a lot faster than a punch from a sleeping spouse. Clonazepam used to be the go-to, and a lot of sleep clinics have quietly moved to melatonin because it’s a lot easier to put up with (Byun et al. 2023), usually somewhere around 3 to 6mg at bedtime. One catch on the evidence though: the controlled trials that measured the actual REM muscle activity found clonazepam knocked it down and melatonin didn’t, so melatonin’s winning on safety, not on raw power. If the dream stuff turns violent, clonazepam is still the bigger hammer.

The dose printed on the bottle is wrong for almost everyone buying it, and the industry has spent twenty years pushing people toward more of it.

Where the marketing falls apart

Take chronic insomnia in your middle-aged guy. He can’t fall asleep because his brain is still wrapping up tomorrow’s 10 AM meeting at midnight. His circadian clock is fine. His problem is hyperarousal, which is when the part of your nervous system that’s supposed to ease off at night just keeps idling at high RPMs, and melatonin doesn’t lay a finger on hyperarousal. He’ll be back in three weeks ticked off that the $24 bottle from Whole Foods did nothing. What helps him is CBT-I (cognitive behavioral therapy for insomnia, the structured kind with sleep restriction and stimulus control), maybe a little trazodone, cutting off caffeine after noon.

Then there’s anxiety. There’s a tiny anti-anxiety effect at the receptor level that some studies have gone chasing, but in real life nobody should be using melatonin for anxiety. It never gets to a dose that does anything useful for that, and we’ve got real anti-anxiety meds if anxiety is the thing you’re dealing with.

And then there’s kids who won’t fall asleep, which is where I’ve got my strongest opinion and the least patience. Parents are handing toddlers melatonin gummies because the pediatrician mentioned it in passing or somebody in the group chat said it worked for her kid. Melatonin in kids isn’t well studied over the long haul, and the little we do have isn’t comforting. It’s a live hormone, and in animal studies it messes with reproductive timing. The kid who can’t fall asleep almost always has a behavioral or environmental reason… screens in the bedroom, no consistent bedtime, a 6 PM nap, mom and dad letting him stay up because they’re wiped too. Fix the environment before you start dosing your kid with a hormone we don’t fully understand the developmental effects of.

Say a parent walks in with a kid who’s been on 5mg of melatonin every night for a year or two, and the kid’s waking up wired at 4 AM, because a megadose of melatonin in a child leaves a long tail that wrecks the back half of the night. Pull the melatonin over ten days, tighten up the bedtime routine, kill the screens at 7 PM, and three weeks later the kid is sleeping through the night on nothing at all. Not to be Chicken Little about it, but this story plays out over and over, and the supplement industry has exactly zero reason to bring it up.

Timing matters more than dose

Take it right at bedtime and it’s just a weak sleeping pill, which it stinks at. Take it three to five hours before the bedtime you’re chasing and it nudges your body clock, the one thing it’s any good for. So for a delayed-phase guy who wants to fall asleep at 11 PM instead of 2 AM, that means dosing around 6 or 7 in the evening, not at 10:45 while he’s brushing his teeth.

The chronobiology labs use 0.3 to 1mg. You can usually track down 0.5mg or 1mg tablets if you go looking. The smallest dose most US stores bother to carry is 3mg, and that’s already higher than what gives you the cleanest phase shift. The 5mg and 10mg gummies all over the shelves are megadoses dressed up like more is better, and they leave melatonin floating in your blood into the next morning, so you wake up groggy. The high-dose gummy is never doing what the label hints it’s doing, and there’s a real chance it’s the reason you feel like garbage tomorrow.

The supplement industry mess

Melatonin gets sold as a dietary supplement in the US, so it skips the whole FDA approval process and the number on the bottle is whatever the manufacturer felt like printing. A study in JAMA in 2023 tested 25 melatonin gummy products and found the real melatonin content ran anywhere from 74 percent to 347 percent of what the label claimed, with 88 percent of them labeled wrong. One product had no detectable melatonin in it at all, just 31mg of CBD. That’s not some fluke, that’s the rulebook for the gummies sitting on the grocery store shelf.

If you’re gonna use it, grab a brand with USP verification on the label, which just means a third party went and tested what’s in the bottle. That cuts out most of the worst offenders. Anybody pushing you a 10mg “sleep stack” gummy on Instagram is working a deregulated market that lets them toss pretty much whatever they want into the bottle, and the FDA isn’t riding in to save you on the supplement side of things. And if your pharmacy can compound a 0.5mg tablet for you, that’s probably more useful than anything you’ll grab off a shelf.

How I think about it

Melatonin’s a niche tool. It’s good for jet lag, it’s good for guys whose clock is truly delayed, it’s good for RBD, and it’s sometimes good for shift work. For most of the folks who come in complaining about sleep, it isn’t the answer, and a lot of them have already been taking it for months at the wrong dose and the wrong time and getting nothing out of it except strange dreams. When I take it off the table I usually end up explaining why for a solid fifteen minutes, because the idea that melatonin is a sleep aid is baked in deep and the supplement industry has spent twenty years pouring more cement on it.

And patient autonomy works the same here as everywhere else. If you’ve heard my take and you still want to pop 10mg every night, you’re gonna. I’m a provider, not a parent, and melatonin doesn’t need my permission anyway. My job is to tell you what it really does and where it falls flat, so when you go pick a bottle at Costco you’re choosing with your eyes open instead of buying the marketing. If you want the playbook: small dose, right time of evening, paired with morning light if there’s a real clock problem to chase, used for a stretch and not forever. Almost nobody shows up running it like that, and that’s pretty much how a perfectly useful hormone turned into one more supplement that mostly does nothing.

Sources

1. Auld F, Maschauer EL, Morrison I, Skene DJ, Riha RL. Evidence for the efficacy of melatonin in the treatment of primary adult sleep disorders. Sleep Med Rev. 2017;34:10-22. PMID 28648359.
2. Costello RB, Lentino CV, Boyd CC, et al. The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature. Nutr J. 2014;13:106. PMID 25380732.
3. Sateia MJ, Buysse DJ, Krystal AD, et al. Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline, J Clin Sleep Med, 2017;13(2):307-349. PMID 27998379.
4. Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag, Cochrane Database Syst Rev, 2002;(2):CD001520. PMID 12076414.
5. Cohen PA, Avula B, Wang YH, Katragunta K, Khan I. Quantity of Melatonin and CBD in Melatonin Gummies Sold in the US, JAMA, 2023;329(16):1401-1402. PMID 37097362.
6. Postuma RB, Iranzo A, Hu M, Högl B, et al. Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study. Brain. 2019;142(3):744-759. PMID 30789229.
7. Byun JI, Shin YY, Seong YA, Yoon SM, et al. Comparative efficacy of prolonged-release melatonin versus clonazepam for isolated rapid eye movement sleep behavior disorder. Sleep Breath. 2023;27(1):309-318. PMID 35141811.