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 of 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.



251 Responses to “Can You Overdose On Melatonin? A Look At The Side Effects And Dosage”

  1. Bumble bee says:

    Hi. I take 3mg of melatonin 30 mi s before bed and it doesn’t seem to be helping. I will wake up at lest five times every night and have really weird dreams that I remember in the morning.
    Am I doing anything wrong?
    This dosage is what the doctor told me to take. I have been on it for two nights and it doesn’t seem to be working.

    • Hi Bumble Bee
      Thanks for your comment. What was your sleeping pattern like before? Is it better or worse with the melatonin, even if you’re waking up? Some people do have vivid dreams with it too – myself included. I’d speak to your doctor asap and let them know what’s happening and they can decide with you what to do.

  2. Marti says:

    I occasionally take melatonin usually early mornings 1-2 o’clock in the morning when my other sleep meds ware off. I take 10 milligrams of melatonin and it has always helped
    to get me back to sleep. Within 10 minutes of waking up in the morning. I must run to the bathroom with explosive diarrhea. I have done the process of elimination and I am fully convinced that the melatonin is the cause of the diarrhea. Do you think if I reduced my melatonin tablet in half would eliminate explosive diarrhea that I have. I might try it Friday night since I don’t have work on Saturday. But just wanted to know if you saw any correlation between diarrhea and melatonin and taking 10 milligrams. Thank you for your answer I hope everything is going well with you.

    • Hi Marti
      Thanks for your comment. Sorry to hear about the toilet issue. It could be due to the melatonin, but it’s impossible to say. The only way to find out is to stop taking it and see if the problem disappears. If you do think you’re having side effects like this, then I think it’s probably better to stop rather than try a lower dose. Perhaps talk to your doctor for some advice and see if the problem is being caused by something else maybe.

  3. Burakkusuta says:

    I have to take 9mg, lower doses never helped. I don’t usually have a melatonin hangover.

    Also, I’ve found that after consecutively taking it for a week to two weeks I have to stop taking it, because it starts to trick my body into feeling like I’d already slept, when in reality I could go 3-5 24hour periods without sleep. That said, when I stop taking it at the right point I continue to have decent or great sleep.

    A question I have is can a higher dosage put me at risk for coma? Like say I took 20mg or some obsenely high dosage?
    (Lastly my mind remains fully active & aware whilst asleep, & it is awesome, I can always take absolute control of my dreams & remember them henceforth. Not only that, but I can continue where I’d left off in a past dream or start a new one *Like game save files* Screwing with the laws of physics beyond what I can explain is fun.)

    • Hi Burakkusuta

      Thanks for your comment. I’m not sure I fully understood the second paragraph – sorry! I think the risk of coma taking 20mg if you already take 9mg without problems is low. But I’d question why you felt the need to take more? It’s unlikely to do anything different from the current dose.
      As for the lucid dreaming – that’s great! I wish I had the ability to do it at will, including the save game concept!

  4. Counting Sheep... says:

    Hello! I recently started taking 5mg of Melatonin. Its so effective. I have experienced the vivid dreaming and Im naturally moody. Also, I noticed I do wake up the next day with a feeling of being hungover. Its not extreme but blah. Would you recommend cutting the pill in half? The form I take is fast dissolves.

    Thank You

    • Hi there
      I think if it’s effective, but giving you some side effects, then you could try cutting the dose and see if you get the positive effects without the negative. And if you’re still not sure after trying that, you can ask your doctor for their advice on whether it’s the right choice for you.

  5. Lois OLeary says:

    Anyone who has chronic insomnia, especially if it takes a lot of medication to just try to get a few precious hours of sleep,should consider being checked for sleep apnea. I worked nights as a nurse,and had really hectic shifts. I was so tired when I got home I couldn’t wait for bed. Even though I took no sleeping aids, and had no noise, I woke up way to often, and I was exhausted. When I started Melatonin, I thought it would help but it didn’t. My daughter came into my room when I was “sleeping” and when I got up she told me, the truth. “Mom” while you were sleeping, I watched you and you were breathing and not breathing. Without knowing, I was gasping a lot just to get the air in. As a nurse, I wasted no time getting to a Pulmonary Specialist. I was tested, and sure enough, I had sleep apnea. Today with help of my breathing machine, I sleep so much better. Even 5 straight hours feels better since I am getting Quality rather than Quantity sleep.

    • Hi Lois
      Thanks for your comment and for your advice. I often suggest to people who have either worked out, or been told, that their breathing is irregular in their sleep to get checked out for apnea. And it may be that indeed insomniacs who regularly wake during the night could be suffering from a breathing disorder. It’d worth getting tested if you do find yourself waking up repeatedly.

  6. Bumble says:

    What is the recommended dosage for children ages 2 to 5 years old? I want to make sure I’m on the safe side. Thank you.

    • Hi Bumble
      Thanks for your comment. My personal view is that even if they are available over the counter, the best way to find out the safest dose is to discuss it with your doctor. I’d also recommend having a read of my article about melatonin for kids which explains in more detail why I think it’s good to talk it through with the children’s doctor.

  7. Ashley says:

    Im 20 and i usually take 3 or 4 of the 3mg so roughly 8-12mg. Ive taken it on and off for about 5 years and it usually does the trick. However I have experienced what Heather mentioned, sometimes i will wake up after 3 or 4 hours, have VERY vivid dreams and irritability. Now that im older ive come to find i have some minor anxiety issues but i definitely feel like they are heightened occasionally when i take melatonin. especially if i stay stimulated after taking it : watching tv, playing on my phone etc. My advice is to follow his advice, after taking it really try to put your mind at ease, focus on relaxing. Try meditation it has done wonders for me !

    • Hi Ashley
      Thanks for your comment. Personally, I’d say that if the melatonin is exacerbating your anxiety it’s perhaps not the best way to tackle your sleep problems. Maybe you could try a lower dose and see if that reduces both the anxiety and the vivid dreams. And as you say, relaxation and meditation are great options of self-help insomnia cures. Maybe in time you’ll be able to sleep better only using those kind of natural techniques.

  8. Beth says:

    Thank you for this article. I too had no idea I was over doing it and taking 15 to 25 a night. I am starting to see it may be effecting me. But wouldnt have realized if I didn’t read about this.

  9. Someone says:

    I’ve taken 8 extra strength melatonin. Mixed with alcohol. Still alive.

    • Hi there,
      I recommend talking this through with your doctor. It’s a lot to take, especially mixed with alcohol. I do hope that you’re ok, and that you have someone to talk to about the way you must be feeling to take this kind of cocktail.

  10. jay says:

    I have been taking an probiotic-fermented Melatonin in
    liquid form. A friend told me about it, I tried it and
    love it. I sleep like a baby now. However if I take too
    much at night, I do feel sleepy during the day. It comes with a dropper. I dont think I would be allowed
    to give the name of the company here but I think it would be easy to look up.

    • Hi Jay
      Thanks for your comment. I think if it works for you, then great. Just don’t take too much if it’s affecting you badly, and also remember not to rely on it in the long term unless you get doctor’s advice saying you need it for a long period of time.

  11. Brandon says:

    Hi Heather,

    Disclaimer: I am not a doctor. However I do and have taken an obscene variety of medications due to Rheumatoid Arthritis. It has been about 2 weeks since your post so I don’t know what your current status is, but I’ll offer my advice at any rate.

    One med I do take often is Methylprednisolone which is a steroid. Taking it causes your body to produce less/stop producing certain chemicals/hormones within the adrenal glands because it senses there is too much already from the pills. Thus it is necessary to wean off the drug to allow your body to gradually begin producing those substances naturally once again. Since Melatonin is replicating something also naturally produced by the body, it is possible your body has limited or stopped producing the melatonin on its own. I would say you should cut back gradually – say step down your dose by 5 mg. every 3 or 4 nights until you get down to 5 or 10 mg., and then from there step down by maybe 2mg. until you get to a comfortable level or stop altogether. If you just stop suddenly then you may find that you’re completely without any melatonin either from orally taking pills or natural production in the body and have all sorts of side effects including, obviously, sleeplessness.

  12. June LEWANDOWSKI says:

    DECEMBER 27, 2015


    • Hi June
      Thanks for your comment. It’s very common for people to sleep much less as the go through life, so it could be that you’re body and brain just don’t need nearly as much sleep as they used to. I think it can be helpful to bear this in mind when thinking about sleep, as it can help you to stress less about how much you should sleep for. Have a look at this article which talks about how much sleep you need according to age. It could be that you only need as little as 5 hours a night for example, but perhaps you’re hoping for 7 or 8.
      Have you spoken to your doctor about taking melatonin? I think that even though it’s available over the counter in the United States, it’s a good idea to check it’s ok to take along with other medicine you make be taking.
      Otherwise, I think the key is like everyone, to follow good sleep hygiene practices. Have a look at the section on sleep hygiene for more about this.

  13. Kat says:

    I took 110 mg tonight! Oops.I’m 13 and I usually take 30mg.

    • Hi Kat
      Hopefully you were ok, since the comment was a while ago now. Do try to stick to the dose your doctor suggests. Did a doctor suggest that dose, or have you or your family decided it’s the right amount? It seems quite a high dose for your age.

  14. Heather Evans says:

    I just read your article and I’m wondering….what do I do now? I’ve been taking 25-30mg of melatonin pretty much every day for the last couple years. For the last two months I’ve had terrible insomnia, never thought it could be the melatonin. Some days I even tried taking the dosage I stated along with a lot of the things you mentioned above as no no’s. Benzos, blood pressure meds, alcohol, and the occasional muscle relaxer. My husband thought maybe it was just causing strange dreams and asked me to stop taking it. I am a very vivid dreamer, but lately they’ve been disturbing so I’ve gone one day without the melatonin. I know it’s only been one day but, I still am not sleeping any better. After 3-4 hours of sleeping I just….wake up. How do I fix this?? I haven’t gotten good sleep in so long, it’s affecting my everyday life! Im so irritable, and I have been mean to people and that’s just not me. Have I already done to much damage?

    • Hi Heather
      Thanks for your comment. I don’t think you’ve already done too much damage. Sleep problems can nearly always be resolved or greatly improved with the right approach. I would imagine that the best first step would be to keep going without the melatonin or other things you’ve tried to help you sleep. Then try good sleep hygiene techniques (have a look at this article). And if you still find after a couple of weeks that your sleep doesn’t improve, I’d suggest talking to your doctor about the on-going sleep problems and see if they can help.

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