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in: Health, Health & Fitness

• Last updated: September 9, 2023

Melatonin: Everything You Need to Know

Sleep is a weird thing. For several hours at night, we temporarily become unconscious and immobilized while having intermittent bouts of hallucinations. 

Weirdness aside, sleep is essential for our health and well-being. It repairs and restores our bodies. People who don’t get enough sleep tend to be physically and mentally sicker than those who do.

Because sleep is so important, an entire sleep industry has sprouted up in the past few decades to help people improve their sleep. One product that has risen to particular prominence in this category is melatonin. 

Melatonin is everywhere. You’ll find it lining drugstore shelves in various forms: pills, quick-dissolve tablets, and gummies. Your friends have likely tried it. You’ve likely tried it. Maybe you’ve even given it to your kids. 

But do melatonin supplements actually work? Do they help you sleep better? Are they safe?

We recently took a deep dive into the research on melatonin to find out the answers to these questions and more.

Here’s everything you need to know about melatonin. 

What Is Melatonin?

Melatonin is a hormone that the body naturally makes. It’s produced in the pineal gland in the brain. Its primary purpose is to help regulate our circadian rhythms so that our bodies know what they need to be doing at certain times during the day. In humans, melatonin starts to naturally increase when the sun sets, and it continues to rise and reach its peak around 2 to 4 a.m.

Melatonin supplements are synthetic versions of the body’s naturally-occurring melatonin hormone. 

Is Melatonin the “Sleep Hormone”? 

Because biological melatonin rises around the time most people go to sleep, it’s often called the “sleep hormone.” This is a semi-accurate description. 

While melatonin tells you when to get ready for sleep, it isn’t the primary driver of sleepiness. That’s the role of another molecule: adenosine. It’s adenosine that actually makes you feel sleepy.

As adenosine levels rise, we start to feel sleepier and sleepier. When we wake up, adenosine levels are at their lowest. As the day progresses, these levels begin to rise. When we feel really sleepy, adenosine is at its highest. 

Want to know why consuming caffeine makes you feel energized? It’s because caffeine blocks the adenosine receptors in your brain.

As mentioned above, melatonin’s primary purpose is to regulate our circadian rhythm. It tells our bodies when they should start relaxing and prepare for sleep. But if adenosine levels are low during this melatonin rise (because you drank a cup of joe before bed, for example), you still might have problems falling asleep. Melatonin might be telling your body that it’s time to hit the hay, but your body doesn’t have enough “sleep pressure” to actually fall asleep

Rather than thinking of melatonin as the sleep hormone, it’s better to think of it as one of several chemicals and processes your body uses to help you fall asleep. 

Do Melatonin Supplements Actually Help With Sleep?

Okay, so melatonin does play a role in our sleep – it tells our bodies that it’s sleepy time. 

But do they actually help us fall asleep faster and sleep better?

I put this question to sleep specialist Dr. Chris Winter, and he said that the answer isn’t very cut and dried, as much of the research done on melatonin has been inconclusive. “It’s absolutely unpredictable,” he told me. 

Once I dug into the research myself, I quickly discovered what Dr. Winter meant. While some studies have shown a benefit to taking melatonin, in others, it performed no better than a placebo.

One scientific review analyzed 35 separate trials that tested the efficacy of melatonin and graded the studies on their quality and the strength of their results. Based on this analysis, it offered conclusions as to whether or not a recommendation could be made for the use of melatonin for certain groups/circumstances, and if so, how strong of a recommendation could be made given the evidence:

For shift workers: No recommendation for use. Melatonin is sometimes suggested for shift workers who work all night and sleep during the day. The idea is that melatonin can help “reset” your circadian rhythm so that it better adapts to this upside-down schedule. While it may hypothetically help, no high-quality studies have yet proven the effectiveness of melatonin for this use. 

For jet lag: Weak recommendation in favor of use. Like the idea of taking melatonin for shift work, it’s thought that melatonin may help those with jet lag adjust to a sleep/wake cycle that’s been altered by travel. There is some evidence that melatonin can improve sleep for those with jet lag, though more research is needed to confirm these findings.

For those with insomnia: Weak recommendation in favor of use. Some studies have shown that melatonin can improve sleep for those with insomnia, while others found it worked no better than the control. One meta-analysis of studies on melatonin supplements for treating sleep disorders found that supplementing with melatonin helped people with insomnia fall asleep seven minutes faster and sleep eight minutes longer (on average) than individuals with insomnia who took a placebo.

For healthy people who just want to improve their sleep: Weak recommendation in favor of use. Here again, the studies are a mixed bag, with some showing that melatonin can improve the sleep of healthy individuals and some showing that it has no effect for this group.

In summary, the evidence for melatonin’s efficacy is surprisingly inconclusive. It may help in certain circumstances, but it may not! Even if it does help, its effect on sleep isn’t dramatic. 

What’s the Optimal Dose of Melatonin?

You can find melatonin supplements in dosages ranging from 1 mg to 10 mg. 

Melatonin is safe, and research suggests you can’t overdose on it. Some studies have had people take up to 1000 mg of melatonin without the participants experiencing any significant adverse effects. The only people who might experience adverse effects from melatonin are individuals with a genetic variant that causes them to have an impaired ability to process blood glucose when they consume melatonin. 

Taking a melatonin supplement also doesn’t affect your natural melatonin production.

So you might be thinking, “Well, if melatonin is safe even at high doses, then the more melatonin I take, the better!”

Not necessarily. 

study out of MIT found that in older adults suffering from age-related insomnia, the optimal dose of melatonin to help with sleep was just .3 mg. 

That’s right. Just .3 mg. That’s ⅓ of a 1 mg melatonin tablet. 

As the professor who headed up the MIT research explained, “Our study has shown that less is more as far as melatonin is concerned.” Not only did the study find that a bigger dose of melatonin had a reduced effect compared to a smaller one, but individuals who took the higher dose tended to feel groggier in the morning. That’s because supplementing with higher amounts of melatonin causes melatonin levels to stay elevated throughout the morning, resulting in a melatonin hangover. 

It’s unclear if this less is more approach applies to taking melatonin if you don’t have age-related insomnia.

But, since it’s possible that less is more for everyone, and because the higher dose of melatonin you take, the groggier you will feel the next day, it makes the most sense to start by taking the lowest possible amount of melatonin to see if it works for you. If it doesn’t, you can increase the dose from there. 

When Should You Take Melatonin?

Melatonin is always taken before bedtime, but the many studies done on melatonin offer different recommendations as to how long before bedtime you should take it. Some say you need to take it two hours before bedtime, while others say you can get away with taking it just 15 minutes before you turn in. 

I’ve taken melatonin an hour before bed or even right before bed. I’ve never really noticed a difference. Experiment and see what works for you.

Can You Take Melatonin Every Night Indefinitely?

As mentioned above, melatonin is safe and has few side effects, even in large doses. So can you take it every night indefinitely?

The answer is that we don’t know for sure. There are some studies out there on individuals who took melatonin every night for six months that showed no adverse effects. But there haven’t been any studies done that followed people who took melatonin every night for years.

Based on the research we have, scientists theorize that supplementing with melatonin every night indefinitely won’t result in harm. It doesn’t appear that you can develop a tolerance to it, so even if you’ve been taking melatonin for a while, you won’t have to keep increasing the dose to get the same effect. However, if you’re having problems falling asleep every night, there’s likely something physical and/or psychological going on, and you’ll get more bang for your buck trying to figure out and solve that underlying issue instead of popping a nightly melatonin tablet for the rest of your life.

Can Kids Take Melatonin?

There aren’t any studies on the long-term consequences of melatonin supplementation in children. We do know that there’s very little danger to kids taking low doses of melatonin in the short term.

That doesn’t mean there aren’t potential concerns around children and melatonin, however.

One hypothetical negative side effect is increased bedwetting; the idea is that melatonin may deepen a child’s sleep, so much so that they won’t wake up to use the bathroom. But then there are studies that show melatonin supplementation may help reduce bedwetting.

Some scientists theorize that melatonin supplementation by children may delay puberty. One study on the issue found that long-term melatonin supplementation didn’t affect puberty, but it’s still something that’s being looked at.

Pediatricians also worry about kids taking too much melatonin. There’s been an uptick in the number of young children going to the emergency room for melatonin overdoses. While the symptoms of overdosing have been mild — drowsiness, nausea, and vomiting — in a few instances, kids have required intensive care. 

Why are kids overdoing it on melatonin? Well, the melatonin supplements parents give kids are usually the gummy variety, and they don’t come in a tamper-proof bottle. A five-year-old can just open up a bottle and nosh on a dozen melatonin gummies in a blink of an eye. Second, the melatonin dosage in these gummies is all over the place. Even if the bottle says that one gummy contains just 1 mg of melatonin, independent lab studies show that it could be much more than that. 

If your child is having trouble falling asleep, before you start giving them a melatonin gummy on the regular, talk to your doctor and potentially see a sleep specialist. They may have a serious sleep disorder that needs to be addressed, not just band-aided with a drug.

Even if your child doesn’t have a serious sleep disorder, defaulting to melatonin gummies when they’re having trouble falling asleep may be setting them up for a lifetime of disordered sleep. You’re teaching them that if you can’t fall asleep, the first thing you turn to is a pill. Instead of giving melatonin to your tossing-and-turning tyke, Dr. Winter recommends taking the time to teach them proper sleep hygiene and not freaking out if they don’t sleep on the exact schedule and for the exact amount of time you want them to.

For more on how to deal with kids’ sleep issues and set them up for a lifetime of healthy sleep, listen to our podcast with Dr. Winter. 

Are There Any Other Benefits to Melatonin Besides Improved Sleep?

While melatonin is primarily taken to improve sleep, there’s been an increasing amount of research showing that melatonin supplementation can benefit our health in other ways thanks to its powerful antioxidant properties. Melatonin supplementation may help prevent or improve conditions like cardiovascular disease, liver disease, and Alzheimer’s. There’s also research that suggests that melatonin supplementation can reduce symptoms of viruses, including COVID-19. Melatonin may even help in cancer treatment

Treating health issues with melatonin is something you’ll want to talk to your doctor about. Don’t do this on your own.

So What’s the Final Word on Melatonin?

Many of the answers to the FAQs around melatonin are frustratingly inconclusive. What does seem clear, however, is that melatonin is not a wonder drug that will dramatically improve your sleep. It may help a little, or not at all. If you’re seeking a more satisfying night’s rest, you’re better off doing all the boring lifestyle stuff you’re tired of hearing about: working on your sleep hygiene, cutting down on caffeine, and building up your sleep pressure through sunlight, exercise, and an all-around active daily routine. 

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