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

melatonin overdoseMelatonin tablets are generally seen as ‘safe’ sleeping pills by most consumers, doctors and scientists. This is largely because Melatonin is a natural hormone which your own body produces.

But is it completely fool-proof safe, or can you overdose on Melatonin? And what kind of side effects can you expect with a normal or high dose?

Technically anything over the recommended dosage can be considered an overdose. The problem is though, Melatonin doesn’t really have an official recommended dosage.

That said, most doctors and researchers say you should take no more than 5mg a day. And preferably less for most sleep problems.

This was also the standard dose we found in most brands during our review of over the counter sleep aids.

So we will look at what might happen if you take more than that dosage. And what symptoms you might expect from a Melatonin overdose.

And if you are interested in more background information, have a read of our article examining how well Melatonin works.

Surely there must be a recommended dosage of Melatonin?

There really isn’t a standard recommended dose of Melatonin at the moment. And interestingly most brands sell it in quantities far higher than the body actually produces.

Melatonin is marketed and sold as a dietary supplement or natural remedy. So it has not undergone the rigorous testing of organizations such as the Food and Drugs Administration in the United States. And therefore there is no central body to say exactly how many milligrams you should take.

So you are left to trust the advice of anyone else who speaks up on the matter. Some good advice from the University of Maryland Medical Center for example 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 go on to suggest that a dose of 1 to 3mg an hour before bed works fine for most adults. But even as little as 0.1 to 0.3 mg might work. And if that dosage of Melatonin 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 if so, how much to take.

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.

And more recently the Mayoclinic also stated that it is safe at a dose of 5mg for up to 2 years. Although on another section of their website they say it’s best not to take it for more than 2 months.

Even at these low doses though 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 medical damage.

What is considered a Melatonin overdose and what might happen?seek help if you take a melatonin overdose

So what happens if you have a bottle of Melatonin 3mg pills which tell you to take one before bed. But you decide to take two or three times that amount, or even more?

Well according to most research, you shouldn’t be in any great danger if you take a small Melatonin overdose.

And in fact it is 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 is 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 the more likely it is that you will experience a ‘Melatonin hangover’ the next day. This is because the Melatonin effectively tells your body ‘more melatonin means it’s time for sleep’.

So when you take it in the middle of the night, your body clock is being pushed forwards. If you are very drowsy the next day then you run a higher risk of having an accident which could harm you or others.

There is no medical advice or research stating what would happen if you took a very high dose of Melatonin. It is highly recommended that you do not consider doing this. At the very least you are likely to experience some unpleasant side effects.

Whatever dose you take, if you start experiencing side effects, then you should seek medical attention.

And if you do take a large Melatonin overdose, intentionally or by accident, it is advisable to seek emergency medical attention immediately. In the US this could be an emergency room or poison control center.

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

Possible Melatonin side effects

1. Daytime drowsiness

Ok you might laugh, but one side effect is of course drowsiness. Yes, it’s like saying on a bottle of milk ‘warning contains dairy products’. But the point is, if you take Melatonin at the wrong time you can end up being drowsy during the day. You are then a risk if driving or operating heavy machinery for example.

2. Hormonal changes

Again this sounds obvious. You are 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.

But it can also reduce the sex drives of both men and women. As well as interfere with women’s ovulation and men’s sperm count. So if you are trying to get pregnant, Melatonin probably won’t help.

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. People who suffer from any kind of depressive illness should not take Melatonin.

4. Hallucinations, paranoia and disorientation

More likely if you take a Melatonin overdose, you may experience hallucinations, delusions, disorientation, confusion and paranoia. These are side effects not to be taken lightly as they can be very disturbing.

5. Increase in vivid dreams and unusual sleep behavior

You may find you have very vivid dreams. It can also increase the possibility of other events such as sleep walking and nightmares.

6. Physiological effects

Melatonin has been found to have several effects on the body. This includes lowering blood pressure, or even raising it if you are 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 cramps and pains, and 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 therefore not use Melatonin as not enough is known about its safety at this time.

10. Serious allergic reaction including rashes and swelling

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 definitely 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 is 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 also interact with other drugs. So you should consult a doctor if you are taking, or planning on taking any of the following:

  • Blood thinners, such as Warfarin or Heparin.
  • Blood pressure medicine, like 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 a  extensive list of exact medications which can interact with Melatonin, have a look at the Webmd article here.


So can you overdose on Melatonin? It would appear that the answer is most definitely yes. But what might happen will depend on many different factors. As with most substances, two people might experience very different symptoms even when taking the same medication.

You can see that there a long list of potentially harmful effects of taking Melatonin. But there are also additional risks for certain people.

So we recommend you stick to the various recommended doses that major organizations such as the Mayoclinic offer.

But first and foremost speak to a doctor to check that it will be totally safe for you. You can also then get clear advice on what dose you should take and how long for.

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

292 CommentsLeave a comment

    • Hi there
      Thanks for your comment. I’d say that’s probably a sign not to use melatonin. There are other options of sleep aids and natural behavioral techniques you can try out. My opinion is that nightmares should be avoided if it’s possible to!

  • If I could fall asleep without melatonin I would. My doctor says I don’t produce enough, so I need to take it every night. I believe him because I’ve tried going without melatonin for a while and I didn’t get to sleep until 6 AM every night. I have depression but it’s improving as I improve my life. It actually gets worse when I’m sleep-deprived. I’ve always had vivid dreams even before I started taking it, so I never noticed any changes in that area. I think I’ll continue taking melatonin until I can find some miracle that works better.

  • I suffer from severe anxiety and it peaks at night if I don’t take something to help me sleep I’m up all night and having anxiety attacks, I started out with Ambien but after about a month it gave me horrible night terrors. My doctor recommended Melatonin. He told me to start with one 10mg at night and see if it helps, I am up to 30 MG a night and it is helping but I’m worried I’m doing more harm than good.

  • I have trouble sleeping through the night and get vivid ass dreams. 5mg didn’t do anything neither did 10mg so I just said f it I need some sleep and took 30mg. Let’s see if this works

  • I can take up to 15mg a night without any apparent side effects. It just depends on the person and their tolerance to melatonin.

  • That would be sadly funny-I’ve struggled with indomnia for over 20 years. My regimine right now is 12.5mg ambien, 600mg seroquel, 15mg mirtazaprine, 2mg lorazapam and 12mg of melotonin. I also drink chamomile tea. For the last 3 months nothing has worked. I’ll lmao if it’s all because I’m taking too much melotonin. I’m going to drop the dose in half and see what happens……

  • Who KNEW! I’ve been taking 10mg each night for about 2 years. I’m never depressed and it doesn’t cause my moods to shift. Always wake up alert and clear. Never really have odd dreams. But now reading I assume there could be other affects I’m unaware of happening to my body. I don’t use melatonin to go to sleep, I can actually fall asleep just find without it. I use it because of the depth of my sleep when I take it. It’s solid and I’m rested.

    Years ago I had a sleeping pill addiction. Started with the over the counter PMs and then moved into prescription types. Then I simply stopped and taught myself how to sleep naturally. It was only recently I tried melatonin and found it really helped me focus and work during the day.

    Thanks for the information here. I will be looking further into other methods and using less.

  • Thanks for all this info. I was taking melatonin 3 mg. for about 10 days and sleeping well, but had an anxiety attack this morning. I still have an earlier bottle, bought at Trader Joe’s. It says take 500 mcg, which is half a milligram . It says: Warning! do not exceed this recommended dosage. And goes on about not mixing it with other stuff, etc. etc.
    I believe Trader Joe’s headquarters is in Germany and think they must have studied it a lot more over there than we in the U.S. did.

  • I think it’s worth mentioning that hormones, such as Melatonin, don’t show a linear dose-response relationship – in other words, lower doses may actually be more effective than higher doses.

    A reference is Lewy et al ( – in this person 0.5mg, but not 20mg, showed efficacy.

    Personally, I started at 0.1mg (which didn’t show much of a response) and found 0.3mg to be efficacious when adopting to time zones after traveling.

    I think many of the doses mentioned on this website may actually be too high and hence counterproductive (see above reference), though it of course depends on the individual.

    • Hi Andreas
      Thanks for your comment. You make a good point there, and it’s another reason why it’s not usually effective for people to keep taking more and more melatonin if they found lower doses didn’t work.

  • My husband took a double of 10mg.of melintonin,he became confused and didnt remember where he was ,he didn’t know what he was doing.I thought he was having a stroke untill I remembered that he took 2…..not good!

    • Hi there
      Thanks for your comment. Sorry to hear the melatonin disn’t agree with your husband. That must have been quite worrying for you indeed. I imagine he won’t be taking it again, even at a lower dose, which is probably the best thing considering his reaction to it.

  • can a doctor just tell you to give melatonin to a child that doesn’t actually have any sleep problems on a daily basis?

    • Hi blair
      Thanks for your comment. Presumably the child has occasional sleep problems? I imagine the doctor might think it’s a good solution to brief spells of sleeplessness. But if it’s not a serious problem, then the parent can always choose not to take the advice and try to help the child sleep using natural methods.

    • Hiyah
      I deleted the long quote with the typo highlighted from your comment, but just wanted to acknowledge and thank you for it. Very kind of you to take the time!

  • I have Fibro, myofascial pain syndrome, lupus, rheumatoid arthritis, and 2 spinal diseases. I never had sleep issues til I wound up with Guillian-Barre Syndrome, then Fibromyalgia. I am up to 16 mg. a night, no help. This has went on with the no sleep since 2007. I was suggested to take the Melatonin, and so far, nothing. Trazodone helped, but my insurance stopped paying for it. I began the Melatonin regimen 40 days ago, with 3mg. At my wit’s end here.

    • Hi Mickey
      Thanks for your comment. Sorry to hear you’ve been having such a difficult time. I think that the melatonin is probably not going to start helping now if it hasn’t after 40 days. I would ask your doctor to try something else instead, and also perhaps really dedicate some time to trying to create as best set of circumstances for sleep as possible. Have a look at my article about healthy sleep habits for a start, and you also might find the article discussing relaxation techniques for sleeping helpful.
      All the best

      • My doc said that if your Insomnia isn’t caused by low levels of Melatonin it won’t work. She said it only helps with sleep if a Melatonin deficiency is the root cause, but can be used to get your sleep cycle back on track with low doses taken at the right times.

      • I have Fibromyaligia very bad too.
        I take 20 mg melatonin just to get some sleep.
        I realize that this is probably not acceptable dose
        But it is the only one that works.

    • Hey if your state has it you should qualify for medical marijuana for any one of those conditions (I was certified for Fibro in IL check out for your state). It can be a greaaaaat help. it’s the only pain reducer I use beyond breathing techniques and being healthy. Meditation while utilizing Medical MJ could be the life changer you are looking for. Best of luck. Don’t ever give up hope that it can’t improve. We have chronic pain but we do get a say in some of how we feel about how we feel.

  • Most of the time, oh I can’t sleep, it’s because m my house or room is too messy, I didn’t get enough activity into my day, or I’ve been looking at a bright screen for too long… or all three! I used to go several nights a week without sleep from the time I was 14 to about 24. That’s 10 years of occasionally losing my mind. I used to take melatonin in high doses, but now I try a few other things first. Stumbled upon this because last night I popped 12mg of melatonin with my hot tea and bowl, and slept until 9.30. Haha, here I was, worried that I overdosed because I didn’t wake up at 6.00 like I usually do. Looks like I’m just getting old!

    • Hi Sam
      Thanks for your comment. It’s good that you usually try other things first. Melatonin isn’t the best to be taking on an on-going basis or in high doses. It’s better as a short-term solution for certain sleep problems. It sounds like you have a good idea of the things which help you sleep, or not, so you should be able to get on top of your sleep by addressing those point as best as possible.

  • I’m trying the natrol advanced melatonin 10 mg..I took one pill 20 minutes before bed with no results, I took another 2 hrs later and still awake, tried another about 1 1/2 hr later with no sleep. Most of the reviews are saying 2 to 5 mg,but my bottle says 10mg..So I took 30mg with zero effect, my question is,do I need to continue several nights for it to get into my system, or would you recommend sominex?Also I drank no alcohol or caffeine before the medication. Thanks

    • Hi Marc
      Thanks for your comment. It may be that melatonin just isn’t going to be the right choice for you. It’s not the same as many other sleeping pills in that it doesn’t just knock you out whatever time you take it. It’s all about re-setting your body clock. So it usually doesn’t help to keep taking more during the night, as you’ve long since passed the time period when it would be most effective by helping your body recognise that it’s time to go to sleep. You could try taking just the recommended dose in the evening for a few more days. If it still doesn’t help, perhaps try something else.

  • I used to be on Ambien 10 mg. every night for 10 years. I was taking it 20-30mg a night near the end. Then I was moved to Belsomra. I do not like the fact that it takes way too long to work and the paralytic side effect is terrible. with the need for sleep paramount for me with my pre existing Ehlers-Danlos, I went back to 100mg of Benedryl and 100 mg of Melatonin. I have been on this for 3 months. I will say the only side effect I have is that I am slightly drowsy in the day, unmotivated, and I have put on 45 pounds since I started this regimen. I will soon be switching back to the sleep meds again as this is what I have been doing for the last 3-4 years. But at 100mgs… I can say I have not had any liver issues.. gastro issues, seizure threshold issues, but the depressive state.. that is pretty much the only thing that bothers me now at this point.

    • Hi there
      Thanks for your comment. I know that at the end of the day, the decision to take sleeping pills is between you and your doctor, but I can’t help think that you’ve been taking sleeping meds for a very long time, and perhaps it would be good to try to find natural ways to sleep better without them. Sleeping pills are best used for shorter periods of time, as I discussed in my article about the advantages and risks of taking sleeping pills. I think even with the side-effects of daytime drowsiness, weight gain and lack of motivation there’s something not quite right there. My advice would be to try to wean yourself off the sleep aids whilst seeking alternative ways to sleep better in the long run. But do talk it through with your doctor first.

Leave a Reply

Your email address will not be published. Required fields are marked *