Have you, or someone you know, taken more than the recommended amount of melatonin and are worried about what might happen to you?
Fortunately, taking a melatonin overdose isn’t known to cause death, but it can cause some unpleasant side effects.
In this article, you’ll find out what dosage sleep experts recommend, how long you should take it for, and what side effects can arise from taking melatonin.
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.
Like many medications, you still need to be careful – even if it’s available over the counter in your country.
How much is an overdose?
If we define ‘overdose’ as an amount which is too much and usually dangerous, there isn’t a clear 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.
That means there’s no central body responsible for setting a recommended dosage.
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 written on the label.
The researchers looked at 31 different brands of melatonin. They found that in 71% of the brands, the stated quantity was incorrect by more than 10%. And 26% of the melatonin pills also contained serotonin.
What might happen if you take a melatonin overdose?
It might be that you take the right dosage just before going to bed, think it isn’t working, and so take an extra one.
Or perhaps you wake up in the middle of the night and take another one to help you go back to sleep.
Although this might 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 or someone you know takes more than the recommended amount, intentionally or by accident, please seek emergency medical attention immediately.
Possible melatonin side effects
Although most people tolerate melatonin well, there are several side effects that can occur even at lower doses.
1. Daytime drowsiness
It might sound obvious, but a key effect is of course drowsiness. It might be a problem if you take it when you’re not planning on going to sleep, or if you still feel drowsy when you wake up.
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
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 breastfeeding
Mothers who are breastfeeding 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 antipsychotics 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 painkillers – 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 (anticoagulants).
For an extensive list of medications which can interact with melatonin, have a look at the webmd.com 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 unwell.
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.