Melatonin is safe for most healthy adults, and experiencing side effects from using it is rare and largely nontoxic. But it’s possible for someone to experience some kinds of mild side effects if they take too much melatonin.
So how much is too much, and what should you look out for when taking melatonin supplements?
How much melatonin is recommended for an adult?
The average recommended dose for healthy adults is anywhere between 0.5mg to 10mg. The dose should be adjusted for children, elderly people, and people who have health conditions that might affect their sensitivity to melatonin.
How much is too much?
The answer is, it depends. Different people have unique sensitivities to melatonin, so the same dose that works for one person might not work for another. What's appropriate for one person might be too much (or even too little) for someone else.
You can’t build a tolerance to melatonin, so you won't get accustomed to a certain amount. But this doesn’t mean that you can’t or won’t feel side effects from taking an amount that is excessive for your body.
Even typically recommended dose of 10mg may be too much for some people. We recommend starting at the smallest dose first, before increasing the amount.
What affects melatonin sensitivity?
One study conducted on light exposure suppressing melatonin production found that some groups of people were much more sensitive to light than others. In this study, some people’s melatonin production was suppressed at very low levels of light, where others required far brighter exposure to have theirs equally suppressed.
These results may provide insight as to why some people may have more easily disrupted sleep cycles than others. But study results about what makes some people more sensitive to different amounts of melatonin than others are not clear.
When should I be careful about taking too much melatonin?
Certain groups of people should be careful about the amount of melatonin they take.
Children and elderly people should consult their physician before taking melatonin. These groups might require a different dosage because of their sensitivity to melatonin. People tend to produce less melatonin as they age, so older people may have a different sensitivity to a certain amount.
People on medication such as those that affect blood pressure should speak with their physician about possible interactions between their medication and melatonin.
People who are pregnant tend to have elevated melatonin levels. There are limited studies on the effects of melatonin on infants and fetal development. Consult with your physician if you are pregnant and are curious about taking melatonin.
Do not mix melatonin with other substances like caffeine, alcohol, or medication that might interact with its effects.
Can I take 20mg of melatonin?
Some people may be able to take 20mg of melatonin safely. 20mg of melatonin could be considered within the safe range for people to take without experiencing side effects.
However it’s very possible that amount may be too high for other people. Start at a much smaller dose before deciding you need more, and very gradually increase your dosage up to 20mg.
How will I know if I took too much melatonin?
It's possible to experience side effects from taking too much melatonin, although these cases are uncommon and nontoxic, even at high doses. Not everyone will experience the same side effects. Some of those side effects include:
- Headaches
- Nausea
- Dizziness or grogginess
- Feeling tired in the morning
- Elevations or drops in blood pressure
- Nightmares
- Agitation or mood swings
If you do experience any of the side effects listed- and you haven’t taken anything outside of your regular routine, aside from melatonin- consult with your physician about continued use.