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Melatonin is a Hormone

Erin Flynn-Evans PhD MPH
Feb 10

Updated and revised from an earlier version based on new science.

A mom and preschooler sitting on a bed

There's not much worse than having your three-year-old ask for 50 things at bedtime, only to get out of bed 100 times (or requiring you to sit in the room for two hours) before finally falling asleep. Supplement marketers have figured out that parents often feel helpless in these situations and offer melatonin as a "natural" solution to sleep problems. Unfortunately, giving a child melatonin often doesn't solve the underlying sleep issue.


Since we originally wrote this blog, sales of melatonin have more than doubled, and calls to poison control regarding accidental melatonin ingestion have increased 530%.


This has prompted researchers and sleep physicians to conduct more studies on how melatonin affects children. In addition, the International Pediatric Sleep Association (IPSA) initiated a Melatonin Task Force that published guidance in 2025 for pediatricians on when and how to use melatonin for sleep issues in typically developing children. We've incorporated their guidance into this blog, but you can read it directly here.


We hope this blog helps you understand why you should think twice before giving your child melatonin. Don't worry; we'll also offer suggestions for how to solve sleep issues without it.

I'd like to start with a bit of my background before we start. I'm Dr. Flynn-Evans. I trained with many of the leading researchers studying melatonin. My dissertation has a 20-page summary of the history of human melatonin production and the effects of melatonin administration. I also run a sleep lab (my day job!), where we measure melatonin in virtually every study we do. I'm also a mom, so you can probably understand why I'm so passionate about this topic!

The Science

Melatonin is a hormone. It is produced in the pineal gland of the brain, and on average, adults produce about 0.3 mg of melatonin a day, but there is a good deal of variation in the amount of melatonin produced between individuals. A person whose body produces more melatonin does not necessarily sleep better than someone who produces less melatonin. Newborns do not have a fully developed pineal gland at birth, and they produce very little melatonin for the first few months. Melatonin is passed through breastmilk, and nursing helps newborn mammals of many species adapt to the 24-hour day. Recent studies suggest this is true for human babies too. Many sleep researchers refer to melatonin as the “hormone of darkness” because if you stay awake all night in the dark, then your body will still produce melatonin. If you turn on a light at night, then your body will immediately stop producing melatonin.

Why should you avoid giving melatonin to your child?

The IPSA Melatonin Task Force recommends that parents do not give their children melatonin. They indicate that melatonin is only appropriate for typically developing children after an extensive sleep evaluation by a physician. There are a number of other reasons why we suggest you avoid giving your child melatonin:


1. Melatonin doesn’t make your child sleep — it changes the timing of your child's sleep.

When you take melatonin as a drug, it is referred to as a chrono-hypnotic (sometimes chronobiotic). “Chrono” refers to time and “hypnotic” refers to sleep, this is because taking melatonin does not make your child sleep per se, it just changes the timing of your child's circadian rhythm. This means that your child's drive to sleep will be shifted earlier, but it doesn’t mean that you or your child will sleep longer. Practically, you may end up with an earlier bedtime, but not necessarily a more well-rested child. In fact, your child’s body clock would shift earlier, leading to an earlier wake time.

2. Melatonin tablets are generally more than 10 or more times what your body produces.

As described above, melatonin does not make you sleep. Children's bodies naturally produce <0.3 mg of melatonin per day, but most melatonin tablets are labeled as 5 mg. Unlike other drugs, more melatonin does not lead to a bigger effect. More melatonin might actually cause a longer melatonin pulse, making it harder to figure out when your child's sleep drive is happening in the future.

3. Melatonin is unregulated in the United States.

Although most people think that over-the-counter substances are safe, the truth is that the tablets that you can buy in grocery stores and natural food stores are unregulated by the FDA. This means that you have to trust that the manufacturer has taken care to assure that the dose in the tablets is accurate. Unfortunately, a few researchers have tackled this issue and found that there is wide variation in the dose of melatonin that you actually get in a pill. This means that you might buy a 5 mg tablet, but some of the pills will have 0 mg and some will have 20 mg. In addition, some studies have found that the tablets contain other supplements or fillers like valerian root, St. John’s wart, and even CBD!

4. Melatonin is the cue for the breeding season in animals.

So far, you might be thinking, “okay, okay, I hear you but I like my more peaceful bedtimes since starting melatonin with my child, and I trust my supplier/brand of vitamins.” Perhaps these next two items will change your mind. As described above, when your child is exposed to light, the melatonin signal turns off. When your child is exposed to darkness at night, the melatonin signal turns on. This is how seasonally breeding mammals are able to tell when to mate — melatonin is a seasonal timekeeper. In sheep, short days/long nights are the cue for melatonin to turn on the reproductive hormones and stimulate breeding. Something similar happens in hamsters and horses, which are long-day breeders. So, how does this relate to humans? We don’t know. Humans are exposed to so much artificial light that it’s hard to determine whether there is a seasonality to our breeding patterns (some old studies suggest there is such a pattern with a spring peak, but there isn’t a scientific consensus either way). There are melatonin receptors all over the human body, including in the testes and ovaries, but we don’t really know how melatonin interacts with human reproductive hormones.

5. Melatonin was once developed as a human contraceptive.

Although it never came to be an approved form of human birth control, the fact that it showed promise in this role will probably make you think twice about giving it to your children.

6. Overconsumption of melatonin has led to death.

No parent would ever deliberately give their child an extreme dose of melatonin but because so many melatonin supplements are packaged as gummies, many children have gotten into their parents' supply and ended up in the hospital. There have been at least two cases of children dying after consuming melatonin.

Is there EVER a time to consider giving my child melatonin?

Melatonin may be helpful for regulating sleep in children who have circadian rhythm sleep disorders, such as in children who are totally blind. There is some limited research to support the use of melatonin in neurodivergent children, such as those with autism as well. In each of these cases, you should work with your child’s pediatrician to create a treatment plan and obtain a prescription for pure melatonin from a pharmacy.


Should I give my child foods to enhance melatonin?

We’ve heard that some parents are giving their kids cherry juice and other foods to “increase melatonin production.” We did a quick literature review on these studies and while these foods may increase precursors to melatonin, the cherry studies were all funded by the cherry industry. We’d like to see some neutral studies on the topic. But, once again, even if cherry juice or other dietary changes did lead to an increase in melatonin production it wouldn’t lead to increased sleep and it would lead to a lot of extra sugar! So, we think it’s better to stick to great sleep hygiene, regular age-appropriate schedules, and proven behavioral interventions to help your child sleep well in the long run.


What can I do to help my child fall asleep without melatonin?

We understand how hard it can be to deal with a wakeful toddler or preschooler during your only adult time. Most bedtime sleep issues can be fixed through a combination of schedule adjustment and behavioral intervention. The right approach to take depends on your child's temperament and sleep history. If your child is testing limits or getting out of bed a lot at bedtime, check out this blog for strategies to help your child settle. If your child is anxious and distressed watching you leave the room, this blog should help get you on track.


Need more help?

If you are concerned that your child may have a medical issue that is interfering with sleep, talk with your pediatrician. If you just need a little help formalizing a plan to get your child to fall asleep more easily at bedtime, please feel free to book a one-on-one consultation with us. We are always happy to help (and yes, we have lots of experience with toddlers and preschoolers!).


As working moms, we always appreciate it when you share our blogs and resources with other parents who could benefit from the information. If you are facing other challenges, then please check out our other blogs, our 0-6 month class, and 6-15 month class. We have blogs on schedules, travel, toddler issues, and more!

 

References and Further Reading

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