Can You Overdose On Melatonin? A Look At The Side Effects And Dosage

a bottle of melatonin pillsMany people view melatonin as a safe sleep aid. And in fact, a safe way to tackle a surprisingly wide range of health conditions.

This is largely because melatonin is a hormone produced naturally by the body, and also because it isn’t as powerful as many prescription sleep aids.

But is it really safe to take, or can you overdose on melatonin? And what kind of side effects might you expect from a normal or high dose?

These are important questions to ask, especially if you plan on giving melatonin to children or using it yourself on an on-going basis to tackle insomnia.

How much is an overdose?

If we define ‘overdose’ as an amount which is too much and usually dangerous, it’s not an easy question to answer.

There are reports of people taking just a few mg and feeling unwell; others have taken hundreds of mg and been absolutely fine.

Melatonin seems to affect people differently, with no standard dosage level which causes most people problems. A second problem is that melatonin doesn’t have an official recommended dosage in most countries.

That said, most doctors and researchers say you should take no more than 5mg a day in most cases. And preferably less if it’s taken for sleep problems. This was also a common maximum dosage level I found when testing different over the counter sleep aids.

Despite often seeing doses between 3mg and 5mg on labels, doctors often suggest that you take the lowest dosage at first, as this may well give the effect you need.

And in fact, it’s thought that even 3mg is considerably more than necessary in most cases.

Why isn’t there a standard recommended dosage?

Melatonin is marketed and sold as a dietary supplement or natural remedy. So it hasn’t undergone the rigorous testing of organizations such as the Food and Drugs Administration in the United States.

Therefore, there’s no central body to say exactly how many milligrams you should take. So you’re left to trust the advice of anyone else who speaks up on the matter.

Some good advice from the University of Maryland Medical Center recommends taking a dose as close as possible to that which the body produces. And the body usually produces less than 0.3mg per day.

They also suggest that a dose of 1 to 3 mg an hour before bed works fine for most adults. But even as little as 0.1 to 0.3 mg might work. If that dosage doesn’t work after a few days, you can increase it to 5 or 6mg.

Even though melatonin is available over the counter in many countries, you should discuss it with your doctor first. They can tell you if it will be safe for you, and recommend the right dosage based on your medical history.

Is melatonin safe at these low doses?

Research in 2005 concluded that taking melatonin at low doses is safe for periods of 3 months or less.

More recently, the Mayoclinic also stated that it’s safe at doses between 1 and 20mg for up to 3 months. They also suggest that it’s safe for children to take long-term in recommended doses.

Even at these low doses, however, you may still experience side effects. Safe doesn’t necessarily mean no side effects – it just means that it probably won’t cause most people any serious problems.

What might happen if you take a melatonin overdose?

seek help if you take a melatonin overdoseSo what happens if you have a bottle of 3mg melatonin pills with instructions to take one before bed, but you take two or three times that amount, or even more?

According to most research, you shouldn’t be in any great danger if you take a small melatonin overdose.

And in fact, it’s common for people to take a pill too soon before bed, decide it isn’t working fast enough and take another one. Then in the night to wake up and take yet another.

Whilst this may not cause you too much trouble, it’s not the right way or safest way to use melatonin.

The more you take, the more likely it is that you’ll experience unpleasant side effects. And importantly, if 1mg didn’t help you sleep, another 1mg an hour later is unlikely to make a difference.

There’s no medical advice or research stating what would happen if you took a very high dose of melatonin. However, it’s not advisable to experiment with higher doses to try and achieve a stronger effect.

Even if it’s not thought to cause death, it’s possible you’ll experience some unpleasant side effects.

Whatever dose you take, if you experience side effects, you should seek medical attention. And if you do take a large melatonin overdose, intentionally or by accident, it’s advisable to seek emergency medical attention immediately.

Possible melatonin side effects

So what are the side effects of melatonin that you might experience at any dosage level? Let’s take a closer look.

1. Daytime drowsiness

It might sound obvious, but one side effect is of course drowsiness. The point is though, if you take melatonin at the wrong time you can end up being drowsy during the day. This could increase the risk of accidents if driving or operating heavy machinery.

2. Hormonal changes

Again this sounds obvious – you’re taking a hormone after all, right? But the effects can be serious in some cases. For example, pregnant women are advised not to take melatonin as it can have negative effects on fetus growth.

It can also reduce the libido of both men and women, as well as interfere with women’s ovulation and men’s sperm count. So if you’re trying to get pregnant, melatonin is probably something to avoid.

3. Mood changes

This is especially likely if you take too much melatonin. You may experience a range of mood changes such as sadness, worsening depression or even feeling over-excitable. If you suffer from any kind of depressive illness, you should avoid melatonin unless your doctor recommends it.

4. Hallucinations, paranoia and disorientation

If you take a large overdose you may experience hallucinations, delusions, disorientation, confusion or paranoia.

5. Increase in vivid dreams and unusual sleep behavior

People often report that they have very vivid dreams when taking larger amounts of melatonin. It can also increase the frequency of sleep disorders such as sleep walking and nightmares.

6. Physiological effects

Melatonin has been found to have various effects on the body. This includes lowering blood pressure, or conversely raising it if you’re taking drugs to control it. It may have effects on blood sugar levels and cholesterol.

It can also bring about further problems for type 1 diabetics. This is due to a reduction in tolerance to insulin as well as increasing blood sugar levels.

7. Risk of seizures

This is a particular risk if you overdose on melatonin or have any existing kind of seizure disorder. Again this can be potentially serious and another good reason to be careful with how much you take.

8. Nausea and other stomach problems

This is one of the more common side effects of melatonin, even at low doses. You may experience nausea, vomiting, stomach pains or diarrhea.

9. Risks to infants through breast-feeding

Melatonin is possibly not safe for infants, even though some sources argue that it’s safe for children. Breast feeding mothers should avoid melatonin as not enough is known about its safety at this time.

10. Allergic reaction

In some rare cases you may experience a severe allergic reaction. This could result in a rash, swelling of any parts of the face, tongue or throat, itching, dizziness and trouble breathing. You should seek immediate emergency medical help if these symptoms occur.

11. Increased risk of contracting immune system disorders

Melatonin may increase the risk of contracting autoimmune disorders such as Hepatitis or Crohn’s disease. For this reason, people who already have an autoimmune disorder should consult a doctor before taking melatonin.

12. Risk of liver damage

There’s thought to be an increased risk of liver damage. This is another reason people who have problems with alcohol misuse need to consult a doctor before taking it.

Interactions with other drugs

Melatonin can interact with other drugs, so you should consult a doctor if you’re taking, or planning on taking any of the following:

  • Blood thinners, such as Warfarin or Heparin.
  • Blood pressure medicine, such as Nifedipine.
  • Drugs to prevent seizures.
  • Drugs which affect your immune system.
  • Psychiatric medications, especially anti-psychotics or anti-anxiety drugs such as Benzodiazepines.
  • Anything containing caffeine or alcohol. Caffeine reduces the quantity of melatonin so makes it less effective. And therefore more likely you’ll decide to take more and risk having an overdose.
  • Anything which can make you drowsy, such as sedatives, some cough medicines and anti-histamines, muscle relaxants, other sleeping pills and some pain killers – especially narcotics.
  • Medication for diabetes.
  • Fluvoxamine (Luvox), which can decrease the amount of melatonin your body can absorb and increase the risk of side effects.
  • Medication that slows blood clotting (anti-coagulants).

For an extensive list of medications which can interact with melatonin, have a look at the article.


So can you overdose on Melatonin? It would appear that the answer is yes, if by overdose you mean feel unwell. But what might happen, if anything at all, is impossible to predict.

As with most substances, the symptoms may vary greatly from one person to the next. Melatonin isn’t known to cause death, but can make some people feel sick.

You can see that there’s a long list of potentially harmful effects of taking melatonin. But there are also additional risks for certain groups of people. So I recommend you stick to the recommended doses that major organizations such as the Mayoclinic offer.

If you’re thinking of trying it, for any medical condition, it’s a good idea to talk it over with your doctor first.

Even though it’s available over the counter in some countries, it’s a good idea to get the approval of a medical professional who knows your medical history. They can also advise you on the best dosage to take in¬† your case.

And once again, if you do take a melatonin overdose, please seek emergency medical help straight away.

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366 CommentsLeave a comment

  • Was taking a 2 pills at a 3mg dose regularly with my usual sleepy pills.

    I accidentally bought a 10 mg pill and took 2 of those. Slept well, but woke up in the morning with heart pounding after having some really freaky dark death and haunting related dreams.

    Gonna keep the dose lower for a while and see if the creepy factor in my dreams goes away. I love having dreams bit thesee ones have been messed.up.

  • I have been taking 3mg of melatonin from a health food store. I’m having major diarrhea. Wakes me up at night and I go all day. Imodium does not work. This is the onl y thing that I have changed. Now that I have stopped taking it, how long will it take to get out of my system?

    • Hi there
      Thanks for your comment. It will probably be out of your system by the time you check this reply! Melatonin usually leaves the body very quickly. If the problems persists tomorrow, I’d start thinking about alternative causes though.

  • Please, please if you feel that you can’t fall asleep on just the recommended dosage of melatonin find something else to take. I had no idea that when I got so depressed and had such severe stomach pains that it was all the melatonin I was taking. The depression was so bad and dark. I had never ecperienced it so bad. It wasn’t until I ran out of melatonin and just grabbed some benedryl to take. Right away the next morning I started to feel better. I’m not saying benedryl is right for everyone or melatonin is wrong for everyone. Know that just because its all natural and is produced in our own bodies doesn’t mean its safe.

  • I have been taking 20 mgs of melatonin at night for over two weeks. I know feel horrible. I have been sweating and hot. I also have the shakes and has really messed up my digestive system. Feeling bloated. I stopped taking it. I think I overdosed on melatonin and my whole system is out of whack. Could these symptoms be because of the melatonin? How long does it take to get out of your system. Thank you.

    • Hi Mary
      Thanks for your comment. Melatonin is usually out of your system very quickly, and definitely by the next morning. However, if you take a lot of it regularly it can take longer to completely clear. The important point though is that if you’ve had these bad side effects, which could well be due to the melatonin, it’s important to speak to your doctor about it.

  • Purely anicdotal: I take melatonin in varying low doses (3 to 10 when the pain gets bad) and I sleep generally well afterwards. My mother couldn’t sleep due to a toothache and I offered her a 3mg. She swore them off the next morning, claiming she felt like she was being dragged down, like she was dying. She has taken them again recently several years later, and found that her sleep was much better, no dragging feeling. It is odd how this little white pill can change effects over a few short years.
    PS. I’ve been taking things like zzzquil along with a 3mg and will sleep soundly much better than usual. I never have dreams when I do this. I have chronic pain problems(upper intestinal problems), so I don’t know if I should recommend that to anyone else.

  • Hi Ethan,
    I’ve been taking 5 mg of melatonin every night for about 2 years. It seems to help, but wonder if it’s just become something I think I need to fall asleep. My main concern is how long can you keep taking it? just turned 60 and I can say, I am still tired after being up for only a few hours. Thank you

    • Hi Rosemarie
      Thanks for your comment. It’s hard to say, but it it possible that it’s become a placebo effect. It’s also hard to say how long you can keep taking it for. The best thing would be to ask your doctor to tell you based on your own medical history.

  • So I have been taking melatonin on a pretty consistent daily bases. After a while just a 5mg didn’t effect me all that much so I went up to a 10mg. But out of pure curiosity what would happendix is someone took maybe 50mg or so?

  • So I have a herniated disc and I take melatonin to help me sleep through these painful nights. Tonight I took 20mg and it made me feel, uneasy. I would normally take anywhere from 3mg to 10mg at night and sleep just fine. After 20mg, I fell asleep but woke up 2 hours later with some pretty horrible anxiety. I just knew it was too much. Now I’m going in and out of sleep with weird hallucinations. I will stick to the lower dosage of 10mg and lower.

    • Hi there
      Thanks for your comment. I hope you recovered quickly from that night’s events. You might find that a much lower dose even helps. I’d try taking 1mg or less and you might find it still has a positive effect.

    • Higher doses of 20mg of melatonin are taken for brain tissue repair (not for sleep), and are usually taken together with GABA to calm overactive neurotransmitters, so that one doesn’t get the anxiety you experienced. So the dosage level is absolutely important depending upon what you’re using it for.

  • I give my children 5mg each school night. Works beautifully. If we’ve been super active and I know they are super exhausted I don’t give them any. During the summer and on weekends I don’t give them any unless absolutely necessary. I’ve talked with their doctor and he approves.

    • Hi Tonya
      Thanks for your comment. I think that’s the important thing – to talk it through with your doctor, and to use it on an as-needed basis rather than a constant basis.

  • What a great article! I’m wary of melatonin, but still love the idea of it. I have trouble trouble sleeping – I’m typing this at 4:30am, having woken up at 3 for some reason feeling ready to start the day – and always heard about melatonin. A couple months ago, I bought a few bottles of it in different amounts and with different other ingredients – one is 5mg with chamomile and other things I can’t recall, for instance.

    I’d started taking a 3mg tablet each night at 10:30, as I have a rotating shift at the hotel where I work, which varies between the day and night hours, but never overnight, so I’m always home by 11:30 regardless of schedule. I wasn’t noticing a change in my sleep patterns, so I took a bit more every few nights to try to find the dose that would help. I don’t know if it was building up in my system or what, but after three weeks of taking melatonin, it was making a phenomenal difference! The most I ever took was 9mg, but I was sleeping better than ever and my mood during the day was delightful. I felt like life was suddenly easy!

    My period was due on or around a certain date, but I missed it. I often have irregular periods so it’s not a big deal, but I didn’t even seem to have pms or any of my usual ‘tells’ of an oncoming cycle. I knew I couldn’t be pregnant, and I hadn’t been eating differently, so the only thing it could’ve been was the melatonin. After a little more than two weeks of my period being non-existent, I finally stopped taking the melatonin in hopes my cycle might fall back into place.

    The day after my last dose, my abdomen was cramping as badly as it had back when I was a teenager two decades ago. The day after that, my period arrived with an awful vengeance, and I became more emotional than I’d been in years. I was crying over seriously anything and everything.

    Ever since, I’m back to sleeping horribly, but I notice now that my gut hurts often. It’s been almost three weeks since the Period From Hell, and my abdomen feels achy, almost like I’ve been working out too hard, though I don’t at all. I’m also endlessly hungry, so I’m really not sure what’s going on. I know melatonin’s a hormone, so it could’ve messed with mine somehow, but I guess I’m concerned about whether it can ever be taken again without causing such problems. I really did love the way I felt when I was on it!

    • Hi Angela
      Thanks for your comment, and I’m glad you found the article helpful. It’s strange that your still getting stomach problems long after stopping the melatonin. I think it would be a good idea to get yourself checked over by a doctor for any other physical causes just to be sure – it’s possible that the melatonin is just a coincidence and there’s something else going on. And depending on what they may or may not find, perhaps they can advise you about taking melatonin or not again.

  • Hi Ethan,

    I used to take Melatonin when I worked, because of stress and number of hours sleep I got (usually about 5-6 hours a night). It induced REM, and that 5-6 hours was like 7-8, woke up well rested and great. Mentioned it to other people. I told them I heard at the time to get a bottle of 1mg tablets and start with 1 and increase each night if it doesn’t work by 4, it probably wasn’t going to work. Got good comments from friends about it… well, mostly. Some said it didn’t work.

    Thanks for the informative read!

    • Hi Phil
      Thanks for your comment, and I’m glad you found the article informative. I’ve given similar advice many times in the comments here, as it’s definitely best to start with a low dose. If it doesn’t work at lower doses, then it’s unlikely to work at the very large doses people sometimes take in the hope it will do the trick.

  • Hi Ethan,
    I suffer from migraine and read about 3mg at night can help the frequency and /or intensity of them. Took for a couple weeks and it did help. I got nervous that maybe it’s too much so I stopped and bam migraine the next day. I started taking again but now I only take half a pill 1.5mg a night. Do you have any information on migraine and melatonin? Thank you, Rachel.

    • Your migraines may be from an issue with your pineal gland. Your pineal gland produces melatonin and other hormones. Believe it or not, it even produces DMT naturally at night while youre in r.e.m sleep which is what makes you “Dream”. If the melatonin takes away your migraines its likely that you have a chemicals out of balance. No big deal. Just talk to your doctor!

  • I told my son to take his chewie. He is 7 and usually listens well he says he took 4 or 5 idk if this is true the bottle didn’t have many in it and still has close to what I thought was in it. Idk if he took any as some nights he puts his chewie somewhere and doesn’t take. I hate to rush to ER if he never took them idk what to do.

    • Hi L
      Thanks for your comment. By the time you read this, you will already have decided what to do. I imagine your son is fine and I hope he is. I think perhaps it’s a good idea to have a talk with him and his doctor about why he doesn’t want to take the chewies. And perhaps find a way to help him sleep better that he feels comfortable with. And of course, keep pills safely locked away where he cant get to them.
      All the best

  • I’ve been taking small doses for a couple months now and then stopped for about a week bc it didn’t seem to work. then on a whim 3 nights ago I took 30mg (3 10mg tablets) and did so for the next two nights but it still took about 45 minutes to fall asleep, then tonight I took 50mg to try to fall asleep faster and after a half hour still not feeling the effects but I guess I should stop again because it doesn’t help much?

    • Hi Dan
      Thanks for your comment. It’s a common hope that taking more melatonin will have a better effect, but it’s usually not the case. I think if you haven’t had good results with the quantities you’ve taken, as you already worked out – it’s not going to work for you at all.

  • Hi Ethan,
    I’m a night shift worker. I have no trouble falling asleep after a shift but find I can’t get more than 5 hours sleep. Am interested in melatonin but unsure of timing. Would I take it after waking aiming to get another 3 hours sleep but not feel groggy or take it before going to sleep to help get the full 8 hours of (day) sleep? When I’m not on night shift I have no trouble sleeping.

    • Hi Sarah
      Thanks for your comment. You would take it before you went to sleep after your shift, or in the evening of your non-shift day if you had problems sleeping at normal times (which you don’t). But I wouldn’t take it after your 5 hour sleep.

  • I take anywhere from 10mg to 70mg or more every night and experience no side affect. I’m almost positive you could never take enough of the stuff to be honest

    • Hi Collin
      Thanks for your comment. I know that it’s often suggested that no amount of melatonin will do you great harm, and there are many anecdotal stories of people taking vast quantities and being fine – at least for now. My opinion though is that there’s no need at all to take anything like the amount you do. If it’s going to work, it will work in far smaller doses.

  • Hey Ethan,

    So I’ve heard mixed reviews about giving children melatonin. We talked to our pediatrician, who suggested it. I’ve got one with Autism & one with a sensory processing disorder. Nighttime is a nightmare, as you can imagine. One takes 0.5mg and the other takes 0.25 then another 0.25 if that doesn’t work. I hate medicating them both, but I figure it’s better than the prescription Clonidine (what one of my kids was taking for sleep).

    Anything you’ve heard about the affect of long term use of melatonin in children? (I have a boy & girl?) I’ve read conflicting research/theories of hormone imbalances, especially in girls. Although I feel like both are taking a fairly low dose. Our pedia also said that kids with Autism usually aren’t even producing enough melatonin anyways.

    Any thoughts?


    • Hi Ali
      Thanks for your comment. I can understand your concerns, as there is an on-going debate about the long-term effects of giving kids melatonin and the effects it can have on the onset of puberty for example. And I’ve also seen suggestions that, as you say, it can be helpful for kids with melatonin.
      I think the best thing is to keep working with your doctor, as they are the medical expert at the end of the day, but also keep yourself informed of developments in the research world around melatonin. It’s still something which isn’t completely understood in terms of the long-term effects of long-term use, so it’s likely over the coming years more will be known.
      I would also focus hard on trying to help them sleep using as many natural techniques as possible. Ideally, the melatonin wouldn’t be used long-term and their sleep patters would be stabilized through natural means. I understand this can be difficult to achieve, but I think it’s important to keep on it and keep trying.

  • I have a real sleeping problem, up all night doing nothing, but lay in bed with or without music trying to catch a nap, at least. but I’ve taken 3, 3mg of Melatonin before (at once), before bed but no drowsiness or sleepiness hit me. June 5th, 16 (tonight) I took 4 pills (at once) of the same mg. hours later, nothing but hunger has striked so i got something light to eat, which now keeps me up cuz I’m eating. If i take 5+ would it help me actually get sleep, or is it bad to be taking so many at once? I’ve taken X bars which i slept like a baby in a crib all night, seemed to help me better than this OTC doctor recommended stuff. i just want sleep, i hate life!):

    • Hi E-Z G
      Thanks for your comment. Sorry to hear you’ve been having such bad problems sleeping and are feeling upset because of it. It’s understandable that a lack of sleep can make you feel bad generally.
      If the melatonin didn’t work for you at those doses, it’s very unlikely to help if you keep taking more. It just doesn’t work that way. I would perhaps look at trying a different type of otc sleep aid. I’d also talk to a doctor to get some advice and support – perhaps they can also help you with how you’re feeling about life generally at the moment.
      I also wrote an article recently about how I personally overcame insomnia. Have a read of that as you might find it helpful.

  • I’ve been taking at least 36to54 ml. each night. I have had absolutely horrible headaches daily. Could this have anything to do with taking it?

    • Hi Sherry
      It’s possible, yes. I would stop taking it for a week and see if the headaches clear up. If not, then ask your doctor to check you out to try and find out what’s causing them.

  • I am taking 5mg of melatonin, which does not help me at all. I have started taking Ambien, 5mg. Is this safe to take every night. I have a friend who has been taking 10mg a night for years and is fine.

    • Hi Pat
      Thanks for your comment. Do you mean is it safe to take the combination of the ambien and melatonin every night? As far as I’m aware, they are generally considered safe to take together. However, you may feel the effects even more strongly, meaning you should be careful what you do after taking them. To be on the safe side, I’d consult your prescribing doctor to get their advice.

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