Can You Overdose On Melatonin?

image of different bottles of melatonin pillsDo you take melatonin pills to help you get through 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, both in small and in large quantities.

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

Did you know?

Melatonin works differently from other sleeping pills, and won’t help everybody with insomnia. If you’re not sure if it’s right for you, these articles might be useful:

Is melatonin safe?

Many people view melatonin as a safe sleep aid because it’s a hormone produced naturally by the body. And it doesn’t provide the strong knockout effect that many prescription sleep aids do.

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 some people unpleasant side effects, which you can find out about below.

How much is an overdose?

a bottle of melatonin pillsIf we define ‘overdose’ as an amount which is too much and usually dangerous, there isn’t a clear-cut 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 known dosage threshold that would definitely cause anybody serious harm. A second issue is that melatonin doesn’t have an official recommended dosage in many countries.

That said, most doctors and researchers say you should take no more than 5 mg a day in most cases. And preferably even less if it’s taken for sleep problems.

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 the sleep experts recommend?

The National Sleep Foundation – one of the leading sources of sleep advice in the U.S. – recommends that you start with the smallest possible dose for insomnia and occasional sleeplessness.

Their current advice is:

Between two tenths of a milligram and five milligrams 60 minutes before bedtime is a typical dose for adults, while children should take a smaller dose. Too much melatonin can disrupt your sleep cycle so start with the smallest dose of two tenths of a milligram and increase it as needed.

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

They say on their website:

The best approach for any condition is to begin with very low doses of melatonin. Keep the dose close to the amount that our bodies normally produce (< 0.3 mg per day). You should only use the lowest amount possible to achieve the desired effect.

Is melatonin safe at these low doses?

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

More recently, the Mayo Clinic also stated that it’s only usually recommended for short-term use – up to two months.

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.

A potential problem to bear in mind is the actual ingredients in supplements bought over the counter. Research published in the journal of clinical sleep medicine in November 2017 illustrates that you might not be getting what’s on the label.

The researchers looked at 31 different brands of melatonin. They found the exact quantity was off by more than 10% in 71% of them – as much as 465% off! And a further 26% of them also contained serotonin.

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 3 mg melatonin pills with instructions to take one before bed, but you take two or three times that amount, or even more?

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

Although this may not result in serious harm, 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 3 mg didn’t help you sleep, another 3 mg 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, please 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

The effects of taking a synthetic hormone can be serious in some cases. For example, pregnant women are advised not to take melatonin as it might 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, you should avoid melatonin.

Although the long-term effects on people are still relatively unknown, there’s evidence that it can have negative consequences for animals. As researchers in 2015 stated:

It is known to have profound effects on the reproductive systems of rodents, sheep and primates, as well as effects on the cardiovascular, immune and metabolic systems

3. Mood changes

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 of melatonin, you might 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 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

Mothers who are breast feeding should avoid melatonin unless recommended by a doctor.

10. Allergic reaction

In some rare cases you may experience an allergic reaction to melatonin. 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 should 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.
  • 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 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. And there are also additional risks for certain groups of people.

So even though it’s available over the counter in some countries, it’s wise to speak to your doctor to ensure it’s safe for you to take based on your personal medical history.

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

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598 CommentsLeave a comment

    • Hi Mark
      I don’t have any exact figures on that. From what I can tell, most medical sites say it’s not common. It’s usually more just a sensitivity to melatonin for people who have some kind of side effects.

  • In doses of 10 mg or higher and with prolonged use; (over 2 weeks), it can be very dangerous. It can exacerbate (or unmask) conditions like glaucoma, and autoimmune diseases like Lupus, Parkinson’s and Myasthenia-Gravis. It is also contra-indicated for those with thyroid disorders, high and low blood pressure, liver and kidney disease and the elderly. People do not realize this and think it is a benign sleep-aid because it is over the counter and claims to be a 100% natural hormone (not a drug), However,…be careful, it can be very detrimental to your health if improperly used.

  • Avoid Melatonin….it is not a sleeping pill, but rather a hormone. It is banned for sale over the counter in Europe and can only be procured by prescription in strengths of 1.0 or 2.0 mg. In the U.S., i have seen bottles as high as 50 mg. and this is way too potent and potentially dangerous.People hear about it and assume stronger is better and have no clue what potency is safe to use for short-term usage. It can also unmask autoimmune and sub-clinical diseases like Myasthenia-Gravis ,Parkinson’s or Lupus and make a person seriously ill.

    • Hi Doreen
      Thanks for your comment. You’re right in that it’s not available in every country over the counter. You’re also right to warn that taking more isn’t better, unless a doctor recommends it.

  • Hello. Last night I took two capsules 10mg each. Slept well all night. But from this morning for 8 hours my feel very dizzy, headache and sick. It my first time be feel so sick and I think from overdose. Can be?

  • I took 9mg today for the first time and I am feeling that my heart is beating too fast. Ohh I feel my heart is struggling to pump blood is it because of 9mg of melatonin. Today.

    • Hi
      It could be due to the melatonin, but it’s impossible for me to say for sure. If you still feel unwell, I recommend calling your doctor or emergency services.

  • Thank you for all this information. I’ve been taking anywhere from 20-70mg per night for 6 months. A few times I’ve had to take over 100mg a night to go to sleep. Guess I’ll have to do something different.

  • Is it safe to take after a heart attack with CAB×2. My sleep cycles are all off, I fall asleep but wake up 3-4 times a night.

    • Hi Linda
      I think this question is best answered by your doctor, who will know your medical history and current situation, so be able to offer you the most accurate advice.

  • I find that 10mg of Dissolving Melatonin, coupled with 100mg of Benadryl does the trick quite nicely. Solid, restful sleep, no drowsiness in the morning. You should reserve this combination for days that you have a solid 8 hour window for sleep.

  • I have some 500mcg melatonin chewable melatonin tablets and find that less is more usually and I bite them in half. I also notice that after taking them two or three nights in a row I have to stop as I feel very tired in the daytime and have to take a nap. I also sleep pretty well after three days or so of taking melatonin with out taking melatonin for quite some time. So I just take them occasionally. However…I purchased a repacement bottle..duh..I should have done to where I purchased the ones I am running out of. My new ones are 3mg in caplet form much higher dose than 500mcgs :0{. So…I don’t know if they will work out for me. Guess I will have to try and see. The higher doses do not help me sleep…rather I experience the opposite and no sleep.

    • Hi Hz
      Thanks for your comment. Is it not possible for you to find the same as you had before? If you felt it worked better, and you’re not happy with the new bottle, perhaps it’s better to find it instead of accepting the new dose you bought by mistake.

    • I have been taking with my sleeping pill yo to 15-20 mg of melatonin as I am chronic insomnia I have to sleep I did not know it was a hormone but I know if you have a head injury in Europe that pump you with melatonin I wish when I had my head injury 15 years ago they would have done that for me.

  • I take like two 3 milligram pills 30 minutes before bed and I knock out better off that than trazadone and I sleep great and don’t wake up groggy

  • I took 30mg one night because I knew that I would have a hard time falling asleep; and went right to sleep but I had a headache.
    I felt fine the next day, but was worried about it. For the last few nights I have had a really hard time falling asleep. I’ve been really tired and have had lots of headaches. (I have also had some soreness in my back.)
    I am aware that I could just be superstitious, but am very concerned. Thanks in advance.

    (I’m a Type 1 Diabetic, don’t know if that’s significant.)

    • Hi Easton
      Thanks for your comment, and sorry to hear you’ve been feeling unwell. It’s hard to say if it’s connected to the melatonin or something completely different. If you’re still feeling like that by the time you read this comment, it might be a good idea to speak to your doctor about it.

  • Hi I have been taking melatonin for approximately a year my tolerance has clumbed.tonieght I took about 30 yes 30 5 mg this is the first time I ever heard of overdosing on melatonin I must have a high tolerance sometimes I can’t fall asleep on this dosage

    • Hi Ronald
      Thanks for your comment. I think taking 30 doses probably isn’t a good idea personally – even if you don’t experience side effects from it, it’s an awful lot to be taking one after another. And if the smaller doses didn’t work for you, there’s a chance the increasing doses won’t either. My advice would be to speak to your doctor about this, and see if they can help you with an alternative.

  • I started to take 5 mg of melatonin, because I can’t stay sleeping through the night, and It doesn’t make me fall asleep, should and would it hurt me if I increase it to 10 mg?

    • Hi Denise
      Thanks for your comment. There’s a high chance it won’t make any difference at all. Melatonin doesn’t have the same knock-out that many sleep aids do, with an increase in dose making the effect greater.

  • I’ve been taking a 10mg dose every night for 2 weeks now. I fall asleep quick but find myself waking up 4 to 5 hrs later with crazy dreams. Im either shooting, kicking someones butt or getting jumped by hoodlums. Im 35 y.o. I shouldnt be having these dreams. After reading all night about it, I see why. It kind of scared me simply because i never remembered my dreams till i started with the pill. Should i continue or stop while I’m still ahead?

    • Hi Carwhiz
      Thanks for your comment. Unfortunately, vivid dreams can be a side effect of melatonin. That in itself can be tolerated, but I guess if you wake up in the middle of the night feeling disturbed by your dreams, that’s not a great outcome. I’d mention it to your doctor to see what they say, but yes, I’d be tempted to stop if it’s not helping you sleep peacefully.

  • Hi Ethan my girl friend takes large doses of melatonin at a time and she has been feeling a few of the side affects listed above and I was wondering what you would recommend we do to help stop these side affects

    • Hi Jerry
      Thanks for your comment. I would recommend stopping taking large doses of melatonin rather than trying to stop the side effects. I’d also recommend she speaks to her doctor about the dose she’s taking, and the side effects she has to see if they think she should be taking it at all.

  • Hello my name is nour and I’m 14 and I take 3mg melatonin before I go to sleep and I keep waking up at 4 in the morning this keeps happening and I have school and I don’t know If I should take more or less or stop completely. It also it takes 2 hours to kick in and I can’t keep waking up I don’t know what to do.

    • Hi Nour
      Thanks for your comment. I think considering your age, it’s a good idea to talk this through with both your family and your doctor, rather than trying to work out the best dosage yourself. Talk to them about how you’re sleeping, how you feel, and why you’re suffering because of your lack of sleep. I think it’s important to be honest and speak openly about things like this. Hopefully they can find a way to help you through the bad sleep. I also recommend taking a look at this section on good sleep habits. Maybe you’ll find something there that helps you that doesn’t involve any medication.

  • Hi I am new to this website. I am 74, male and always have had a sleeping problem for ages. I was prescribed Ativan 1mg which went up to 2mg and now I have been trying to reduce the dosage. Someone told me to take Melatonin and I have tried melatonin 5mg with .5mg of ativan. It did not help me much but now I take 8mg melatonin with .25mg of ativan which gets me to sleep 3 to 4 hrs a night. I have come to observe that there is a very gradual decrease in my weight which may or may not be due to the combination of medication. I have not discussed this with my doctor yet.

    • Hi Manny
      Thanks for your comment. Personally, I think it’s a good idea to talk over any new medication combinations with your doctor, just to be on the safe side. And if you’re concerned about the weight change, they should be able to help you work out what might be causing it.

    • Hi Maria
      It’s difficult to say what the effect might be. But I do think it would be a good idea to talk to someone you can trust about why you decided to take so many pills at once. I don’t know what’s going on for you, but I suggest and hope you can find someone to talk this through with.

  • First, a question. If the normal recommended dose is 5mg, why do they commonly sell 10mg tablets?
    Secondly, ive taken 5 and 6 10mg at a time, and felt fine, other than being a little groggy in the morning, and sometimes not remembering falling asleep. But its the best sleep ive ever had, and wake up feeling like a new person.

    • Hi Jeffrey
      Thanks for your comment. That’s a very good question! I think it’s because in some countries where it can be bought over the counter, there’s a lack of regulation. So perhaps some manufacturers capitalize on that by adding more mg to attract more sales from people who think more = better. But also, in some situations doctors can recommend higher doses, so I imagine the higher doses are available to cater for those people. But really, I’m just thinking out aloud here.

    • Hi Alice
      you mean you take 8 pills, so 80mg in total? I think that sounds like quite a lot to me. Have you spoken to your family doctor about this dosage? I think it would be a good idea to do so.

  • Hey I usually take 4-5 melatonin pills that are 5 mg and I’m not sure if anything bad is going to happen or not and I’m also not sure if age or weight has anything to do with this but I’m 15 and 147 lbs

      • Hi Miranda, I would like to think your parents are helping with this. The dose is too high and it is not a drug that induces euphoria. This only helps your hormones to produce melatonin which your body already makes. It’s useless to add more as it could make you feel sick, dizzy or any of the many side effects that are listed here. Please only take what you were prescribed or what’s written on the bottle and if you’re still not sleeping, stop the tablets and get doctors advice

  • Ive noticed that if i take more than 9 mg at night, i have flu like symptoms and feel awful the next day. Interesting article. Ty

    • Hi Jackie
      That’s a lot of melatonin. I think it’s a good idea to talk with her about the quantity she’s taking, and if she’s willing to ask her primary care doctor for their opinion and help.

  • Hi, I have been having trouble sleeping due to menopause issues. I am 56 years old and take Natrol advanced melatonin10mg time release tablets at night. I sleep better, but wake slightly and than in a few minutes fall back asleep. I would usually wake up and stay awake for an hr or so and had bad headaches and couldn’t sleep so would take ibuprofen. Now I don’t get headaches and take no ibuprofen. I don’t have any side effects. I wake up fine and actually my mind is more clear. Is this safe to use for monthes or how long can this be used?

    • Hi Lavonne
      Thanks for your comment. The best thing is to discuss your dosage and length of time taking the melatonin with your personal doctor. Having said that, what I can say is that 10mg seems like quite a large dose – was this prescribed or are you taking it over the counter? And as for the long term effects, the jury is still out on what the long term effects are, though from what I can tell many people do tolerate melatonin well for long periods of time. Again though, it’s something to discuss with your doctor and make a decison based on your medical history.

  • Hello,
    My 14 year old daughter is having problems falling asleep and sleeping well, and was giving a prescription for 3mg Melatonin tables, to take one each night. 2 months later, it doesnt seem to be working. Is it safe to up her dose to 6mg (2 tablets) per night? These sleepless nights are causing havoc at school…
    Thank you

    • Hi Maya
      Thanks for your comment. I can understand how frustrating it must be for you if she’s not sleeping and it’s interfering with school life. It’s not my place to advise you on her dosage though – that’s something that needs to be discussed with the prescribing doctor.
      Sorry I can’t help more!

    • This happened to me eventually it wears off (it took me about a year). Its just a hormonal thing to do with puberty I think because my brother had it at around the same time (12)

  • Hi I’m curious I normally take 2 fast dissolving tablets before I go to bed every night and I’m wondering if that is bad. It says on the bottle that it is 6mg per tablet I believe. Any idea on how much you’d recommend on taking? I use to only take one but it never helped and normally two helps but I also sleep in really late.

    • Hi Alyssa
      Thanks for your comment. Usually for most people 12mg would be way more than necessary to help with sleep. But if you do feel it helps, but then causes you to sleep too much, that’s another issue to think about too. If you’re not sure about dosage, I’d speak to your doctor about it to get their advice. Even if it’s available over the counter in your country, it’s still worth checking with them.

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