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

image of different bottles of melatonin pillsDo you take melatonin pills to help you deal with frustrating periods of bad sleep? Have you taken more than the recommended amount and are worried about what might happen to you?

In this article you’ll find out about the known side effects that can arise from taking melatonin.

I’ll also explain why there’s still some debate about what the recommended dose should be, and what would be considered an overdose.

Did you know?

Melatonin works differently from most sleeping pills, and isn’t always effective for insomnia. If you’re not sure if it’s right for you or your family, you might like to read these articles:

Is melatonin safe?

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

Even though synthetic melatonin is similar to that produced in your body, it doesn’t come without risks though. And like many medications, you still need to be careful even if it’s available over the counter in your country.

The bottom line is that taking more than the recommended amount isn’t known to cause death. However, it can cause health problems in some cases, so it’s worth being aware of what to look out for.

How much is an overdose?

a bottle of melatonin pillsIf 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 milligrams and feeling unwell; others have taken hundreds of milligrams and been absolutely fine.

Melatonin seems to affect people differently, with no standard dosage level which causes most people problems. A second issue 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 5 mg a day in most cases. And preferably much less if it’s taken for sleep problems. This was also a common maximum dosage level I found in my review of over the counter sleep aids.

Despite often seeing doses between 3 mg and 5 mg 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 3 mg 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.

What do doctors recommend?

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 0.3 mg 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 6 mg.

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 1 milligram didn’t help you sleep, 1 more milligram 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.

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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493 CommentsLeave a comment

  • I get nightmares when I take me lat on in so I will no longer be taking them & I only took 40mg….not for me

  • My sleep doc told me that only a low dose is needed to be effective. We started with half of a 5mg tablet. After about a week, I didnt notice the effect of feeling sleepy like at first.

    I am obese so I’m wondering if the amount of fat I’m carrying is making it less effective. I did try increasing to a whole tablet (again, it’s only 5mg but I don’t want to become sleepy during the daytime.) Ultimately, I’m wanting to know how obesity affects meltonin efficacy. Thanks!

    • Hi Ella
      Thanks for your comment. I don’t think it should make much of a difference, and I can’t find any research about this after reading your question. I think it’s something to discuss with your doctor though to get the dose right – but they are right ultimately – only very small doses work, and even 2.5mg is much more than really necessary. I think it’s important to look into how melatonin works, so you understand that it’s not meant to make you feel very sleepy or knock you out, leading you to wonder why that doesn’t happen.

    • Hi there
      It’s impossible to say. But I’d say if you’re doing that, it’s important to talk to someone you trust about it and get some support with dealing with whatever it is that’s making you want to keep overdosing on it.

  • my mother has a hard time sleeping at night and so she takes melatonin and when she does she takes four 10 mg and sometimes it makes her goofy and I am worried if she will be ok I take two 10 mg with zzz quill and I go to sleep within three hours and I sleep for four hours

    • Hi Jackie
      Thanks for your comment. There’s really no need to take 40 mg in most cases. Perhaps try explaining to her that it’s not something that scales in effectiveness with the dosage.

  • Ethan I think it’s awesome that you are helping people out with their sleep issues. I also have sleep issues have tried everything from sleeping pills to a shot of whiskey before bed. I think stress and restless mind is my biggest issue. I am new to trying melatonin ! So what is best strategy for sleeping ? I bought 10 mg dissolvable pills. Thanks for the help !

    • Hi Blake
      Thanks for your comment, and kind words. There are many different strategies for sleeping, and different things work for different people. Having said that, there are some techniques which I think many people would benefit from. If you’re interested, you might like to read an article I wrote about how I personally tackled insomnia and the things that most helped me.

  • My daughter is 4 and just about every night I give her a 1 mg children’s melatonin from the Zarbees brand. She knows it is routine so tonight she somehow got the bottle open herself and then after she was laughing and said she took 2. She went to sleep about 30-40 mins after (like usual) but I am just scared if she’ll be ok since she took an extra mg.

    • Hi there
      I’m sorry it took me a few days to reply to your comment – I do hope your daughter was OK – I’m sure she was even with the two tablets. If something like this happens again, it’s best to call your family doctor or emergency services if you feel she’s taken a potentially serious overdose. Unfortunately, it usually takes me – as most online writers – time to get round to reading and replying to all the comments.

  • Ok so I have three kids I have. Hard time stay asleep I buy the gummies vita fusion take two for 3 mg and some how my son took some he took them like 40 min ago and still awake watching TV should j be worried or will he be ok …. I seen the new here when I live mother’s giving there kids 100 mg just to go to bed I asked him how much he took he said 5 so that’s 7 1/2 mg will he be ok???

    • Hi Krissy
      Thanks for your comment, and I can understand your concern. I imagine he will be OK with that amount, but if you’re worried about your kids taking any substances or medicines like this, it’s best to call their primary care doctor or emergency services. I’m not a doctor, so am not qualified to tell you with 100% certainty what you should or shouldn’t do, and even less so in the comments of a blog. So I do recommend speaking to a medical professional in cases like this.
      I do hope he’s ok though.

    • Hi Person
      I think it would be important to contact your doctor or emergency services, both to get help with the potential ill effects of taking so many, and also to talk to someone about what led up to taking so many in the first place, and get help with the way you might be feeling.

    • Why in tarnation would you need 50 mg? I take 10 and if I take 5 and still can’t relax to sleep I will take another 5mg. I wouldn’t take 50mg for any reason. Please be careful as this amount could cause problems.

  • I recently landed a new job and took as much as 35 milligrams just to get to sleep at night. The company had me up very early and working late in the evening.

    I found that I was experiencing issues with memory and focus. Some days I couldn’t even remember what month it was. Too much of a good thing became a bad thing for me.

    • Hi Sara
      Hopefully she was ok, as you wrote this comment 2 days ago. How old is she? Does your family know that she took this quantity? It’s not a good idea to take so much melatonin in one go, so maybe you could ask her to talk to someone about this, and see if she can get help for her sleep problems that doesn’t involve taking lots of pills.

      • I take 12(every two = 3 mg) every night. I have been taking the 12 for a year now. I am 72 yrs old. Without the melatonin there would be NO sleep. I’ve had sleep studies done and seen a neurologist about my insomnia. I do have restless leg syndrome that I’ve been RXed Gabapentin for that. Besides that, no one has ever really helped me. I believe that with the constant insomnia and days, weeks even months, years while getting only maybe 1-2 hours of sleep per night, that i would die. For me, I feel the 12 melatonin per night have probably saved my life. I do know it is a lot but I would rather take that than sleeping pills.

  • I eat these like candy just because they taste good. 8-10 5 mg doses of the gummy variety. I don’t know if they do anything but I should probably stop. This article and comments makes me worry. Mmm, goodnight zzz

    • Hi Ryan
      Thanks for your comment. I’m glad the article made you worry a bit, because you should’t eat the melatonin like sweets. Maybe you could get yourself a replacement that’s harmless like normal gummy sweets?

  • Is it okay to take 15 mg. I tried 2 pills and I wake up during the night. What about side effects. I read something about cancer.

    • Hi Cathy
      Thanks for your comment. I’m afraid I can’t be responsible for telling you how much is ok to take or not. But my advice would be that if you want to take more than the recommended dose on the type you bought, I’d check with your doctor first.

  • I am 13 and I often take about 200mg sometimes to fall asleep after being sad. The worse thing that happened to me was violent vomiting and fainting when out of breath

    • Hi Hh
      Thanks for your comment. Have you spoken to your doctor, family or someone you can trust about this? I think it’s really important that you tell someone honestly how you feel, what you do when you feel sad, and what happens. Hopefully you can get some help, reassurance and support for the way you sometimes feel.

  • Overdosing on Tylenol can destroy your liver! I am a nurse and have seen people waiting for a new liver from Tylenol overdoses…unfornately there are not enough available livers …so patients have died waiting for a new liver!

      • Because if you read any of the comments above there was someone who took Tylenol regularly instead to get to sleep. Now that is foolish.

        • That is stupid! ** Pardon me** cough cough** that is just plain retarded! Wait… That doesn’t sound right either! Anyways my point is… Not trying to judge as I’ve taken 100 extra strength Tylenol to a suicidal overdose and I’m sorry, but Tylenol, doesn’t make you sleepy!!!

  • I’m a 49 year old female who initially several years ago was diagnosed insomnia. I was on ambien for a few years but when I switched my insurance company, I was told to take melatonin instead. I started with one pill (5mg) and it didn’t work and I continued to increase until I was able fall asleep and stay asleep which is at (30mg). I have been doing this for about 2 years now. I recently informed my doctor about my dosage and she said that she did not think that was normal and she would have to look into that. If the lower dosage did not work for me what should I do? What affects would this have on me? The only thing I have noticed is that my hair is thinning but I chalked that up to age, could this be a side affect.

    • Hi Elegant
      Thanks for your comment. If you look at medical sites online, most say that even lower doses of melatonin are more than enough usually. I’m not sure why people sometimes feel that much higher doses work – perhaps there’s a placebo effect. But I think perhaps if you try the lower dose for longer, you might find it still works as much as the higher.
      As for the hair, I don’t know of any research saying it’s a possible side effect of melatonin.

    • I took ambian for years also. It got to the point I was only sleeping for 4 hrs then was wide awake. I switched to melatonin I take 20 MG but also take 2 prescription anxiety pills at the same time on an empty stomach is better and I sleep most of the night without being drowsy the next day.

  • So I overdosed on like almost a whole bottle of 10mg, I’m 15 yrs old and I have overdosed before when I was 14 on a whole bottle of Tylenol and aspirin, it didn’t do much just made me vomit and that’s all. Anyways now my stomach really hurts and I feel like vomiting just like the other Time, I just want to know what side effects am I going to experience?

    • Hi there
      I couldn’t say what side effects you will experience, but I strongly recommend speaking to your family and calling the emergency medical helpline in the country where you are from.
      I’m very sorry to hear you feel like taking an overdose, and I do hope you can find the support and help that you need.

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