Have you taken more than the recommended dosage of melatonin and are worried about what might happen to you?
Taking a melatonin overdose isn’t known to cause death, but some people might experience side effects such as headaches, dizziness or nausea.
In this article, you’ll find out what dosage sleep experts recommend, and what side effects can arise from taking melatonin.
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. As with any medication, you still need to be careful – even if it’s available over the counter in your country.
However, a range of clinical studies have concluded that melatonin is safe for many adults (except some specific groups – see special
In general, animal and human studies documented that short-term use of melatonin is safe, even in extreme doses.
Long-term safety of melatonin in children and adolescents, however, requires further investigation.
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, the standard advice is not to 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 sleep experts recommend?
The National Sleep Foundation 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.
The Healthline website also recommend starting with a lower dose, adding that other factors such as your body weight and age play a role:
In general, a dose between 0.2 and 5 mg is considered a safe starting dose. A safe dose will depend on your body weight, age, and sensitivity to the supplement.
Is melatonin safe at low doses?
Researchers in 2005 found evidence that taking melatonin at low doses is safe for periods of 3 months or less.
The Mayo Clinic also advises that it’s only usually recommended for short-term use:
Your body likely produces enough melatonin for its general needs. However, evidence suggests that melatonin promotes sleep and is safe for short-term use.
Finally, the National Center for Complementary and Integrative Health says on their website:
Melatonin appears to be safe when used short-term, but the lack of long-term studies means we don’t know if it’s safe for extended use.
Safe doesn’t necessarily mean no side effects though. It just means that it probably won’t cause most people any serious problems. Even a low dose can cause some people
Melatonin supplements might contain other ingredients
A potential problem to bear in mind is the exact 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?
So what happens if you have a bottle of 3 mg melatonin pills with instructions to take one before bed, but you take more?
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
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 any sleep aid.
Don’t keep increasing the dosage
The more you take, the more likely it is that you’ll experience side effects. If 3 mg didn’t help you sleep, another 3 mg an hour later is unlikely to make a difference.
Unless your doctor advises it, it’s not recommended to experiment with higher doses to try and increase the 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, please seek emergency medical attention immediately.
Melatonin side effects
Although most people tolerate melatonin well, there are side effects that can occur even at lower doses.
According to NCCIH, possible side effects include:
Webmd also adds the following in their side effects section:
- Short-term feelings of depression
- Daytime sleepiness
- Stomach cramps
Interestingly though, researchers in 2016 found that there were generally only mild side effects in studies, and often not much different than people who took a placebo:
In general, animal and human studies documented that short-term use of melatonin is safe, even in extreme doses. Only mild adverse effects, such as dizziness, headache, nausea
andsleepiness have been reported. No studies have indicated that exogenous melatonin should induce any serious adverse effects. Similarly, randomized clinical studies indicate that long-term melatonin treatment causes only mild adverse effects comparableto placebo.
Special precautions: who should avoid melatonin
Health sites such as Mayo Clinic, Healthline and WebMD list some special circumstances in which melatonin could have an adverse effect. If any of the following apply to you, check with a doctor before taking it:
- Pregnant or breastfeeding women
- Women who are trying to conceive
- People with bleeding disorders, depression, high blood pressure or seizure disorders.
- People with dementia
- Transplant recipients
Interactions with other drugs
Melatonin can interact with other medications. It’s a good idea to consult with your personal doctor if it will be safe alongside any medication you currently take.
And according to webmd.com, the following are known interactions to be particularly aware of:
- Other sleeping
pills / sedativemedications, for examplebenzodiazepines, Ambien and Clonazepam
- Birth control pills
- Medication for diabetes
- Medications that slow blood clotting
- Verapamil (Calan, Covera, Isoptin, Verelan)
- Nifedipine GITS
- Flumazenil (Romazicon)
- Medications that decrease the immune system
- Fluvoxamine (Luvox), which can increase the amount of melatonin your body can absorb and increase the risk of side effects
It is possible to overdose on melatonin – 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 will vary from one person to the next. Melatonin isn’t known to cause death but might make some people feel unwell. 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.