What Is Melatonin and Why Do People Take It?
Melatonin is a natural hormone that your body makes to help you sleep. It plays a big role in managing your sleep schedule—also called your “circadian rhythm.” This hormone tells your body when it’s time to feel sleepy and when it’s time to wake up. Some people who have trouble falling asleep or staying asleep take melatonin as a supplement to help them rest better.
Melatonin supplements are often used to help with things like jet lag or sleep problems. They can make it easier for you to fall asleep, and sometimes even help you sleep longer. But for some people, melatonin can also cause vivid dreams or even scary nightmares. Let’s learn why that happens and how to make it better.
Does Melatonin Cause Nightmares?
Yes, melatonin can cause nightmares in some people—but not in everyone. Some people take melatonin and sleep well with no problems at all. But others may have bad dreams or scary nightmares when they take it, especially kids.
Why is this more common in children? It’s because children naturally spend more time in a special stage of sleep called REM sleep. REM stands for “Rapid Eye Movement,” and it’s the part of sleep when dreams usually happen. When we’re young, we have more REM sleep, and as we grow older, we have less of it.
Scientists have found that melatonin can increase the amount of time you spend in REM sleep. This means you might have more dreams—and if your dreams are scary or intense, they can turn into nightmares. So if you’re taking melatonin and having more nightmares, it could be because you’re spending more time in this deep dream stage of sleep.
How Does REM Sleep Affect Dreams?
Sleep happens in different stages, and REM sleep is one of them. When you first fall asleep, you go through three stages of non-REM sleep. These stages help your body relax and repair itself. The last of these stages is deep sleep, when it’s very hard to wake up.
After about 90 minutes of sleeping, you enter REM sleep. In this stage, your brain becomes more active again—almost as active as it is when you’re awake. This is the part of sleep where most dreams happen. At first, REM sleep lasts only a short time, but as the night goes on, each REM stage gets longer.
Because your brain is working more during REM sleep, your dreams can feel really vivid and lifelike. Melatonin makes you spend more time in this stage, so if your dreams are already very strong, they might become even more intense—or even turn into nightmares.
Why Does Melatonin Make Dreams So Vivid?
There’s another reason why dreams can become more intense with melatonin. During REM sleep, melatonin releases a chemical called vasotocin. This chemical helps your brain “clean up” memories—it forgets the ones you don’t need and keeps the ones that matter. Scientists believe that vasotocin plays a big role in dreaming.
When you take melatonin, the amount of vasotocin in your brain may go up. This can lead to longer and more intense dreaming. Sometimes, this can mean you remember your dreams more clearly. Other times, if your dreams are scary, it might feel like a nightmare.
Don’t worry, though—melatonin doesn’t erase all your memories. In fact, after melatonin breaks down in your body, some of the leftover parts can actually help improve your long-term memory.
Melatonin Nightmares vs. Melatonin Dreams
Some people who take melatonin get nightmares, while others just get more vivid or interesting dreams. But what’s the difference?
A nightmare is a scary dream that usually wakes you up. It can make you feel afraid, stressed, or upset. Your heart might be racing when you wake up, or you might be sweating. A vivid dream, on the other hand, feels real and clear, but it doesn’t usually make you feel afraid. You might remember it in the morning, but it doesn’t leave you feeling bad.
People who are dealing with stress, trauma, anxiety, or sleep problems like sleep apnea or insomnia may be more likely to get nightmares. That’s because their brains are already more sensitive to fear or worry. So if they take melatonin and have more REM sleep, it could make those feelings stronger in their dreams.
Luckily, most of the time these side effects go away on their own after a few days—or they stop right away if you stop taking melatonin.
Can Melatonin Help With Night Terrors?
It might sound strange, but melatonin can actually help some people who have really scary sleep problems, like night terrors or seeing things that aren’t real while they sleep. These are called “nocturnal hallucinations.”
In one study, people who saw frightening things at night found relief after taking 5 milligrams of melatonin. Their night terrors went away almost immediately. Another type of melatonin—called delayed-release melatonin—also helped by reducing how often these scary events happened.
So while melatonin can cause vivid dreams or nightmares in some people, it might help others sleep more peacefully.
How Do I Stop Melatonin Nightmares?
If melatonin gives you nightmares, don’t worry—there are ways to fix it.
The first thing to try is lowering your dose. Doctors usually recommend starting with a small amount, like 1 to 3 milligrams. Taking too much melatonin can cause side effects like bad dreams, feeling tired the next day, or even dizziness.
You can also try taking melatonin earlier in the evening. A study showed that taking it 2 to 4 hours before bedtime helped people sleep better and feel more rested.
It’s also really important to choose a good-quality melatonin supplement. Since melatonin is not strictly checked by the government like medicines are, some brands might have too much or too little in each pill. One study found that the actual amount of melatonin in some supplements was way off from what the label said. To be safe, look for supplements that say “USP Verified” on the label—that means they’ve been tested for quality.
Lastly, think about other things that might be causing your nightmares. Eating sugary or dairy-heavy foods before bed might make dreams more intense. Also, check if your supplement includes other ingredients. For example, valerian root is sometimes added to sleep aids and is known to cause vivid dreams.
Navigating Melatonin’s Side Effects
If you’ve done all of the above—taken a smaller dose, taken it earlier, and checked your food and supplements—but you’re still getting nightmares, it’s time to ask yourself: is melatonin helping you sleep?
If it’s not helping at all, just stop taking it. You don’t need to wean off melatonin—it’s safe to stop suddenly.
If melatonin is helping you sleep and you want to keep using it, you can try adding calming habits before bed. These can help you relax and lower your chances of having bad dreams.
Try making a bedtime routine that helps you feel calm. You could drink a cup of warm herbal tea, write in a journal, listen to soft music, or meditate. Even just reading a book for a few minutes can help your brain settle down.
If you’re having nightmares often, it might also help to talk to someone. A friend, family member, or therapist can support you and remind you that you’re safe.
Cuddling with a pet, stuffed animal, or even a cozy blanket can make you feel more relaxed too. Some people also feel better with a nightlight on. Choose a dim red light instead of a white or blue one, since red light won’t mess with your sleep as much.
Other Melatonin Side Effects
Nightmares are just one possible side effect of melatonin—and they’re not very common. But here are some other things people might feel after taking it:
Headache
Dizziness
Nausea (feeling sick to your stomach)
Feeling sleepy during the day
Daytime sleepiness is the most common issue, but you can fix it by taking a smaller dose or taking melatonin earlier in the evening. Also, try using regular-release melatonin instead of time-release versions, which can stay in your system longer.
Other rare side effects can include:
Feeling depressed
Shaking or tremors
Anxiety
Stomach cramps
Irritability or mood swings
Confusion
Low blood pressure
If these side effects happen often or don’t go away even after changing the dose or timing, you can safely stop taking melatonin.
Conclusion
Melatonin is a natural and usually safe sleep aid that helps many people fall asleep and stay asleep. It’s not habit-forming and doesn’t have as many side effects as stronger sleep medicines. But for some people, melatonin might cause vivid dreams or nightmares—especially if they take too much or already have a lot of stress.
If this happens to you, start with simple changes like lowering the dose or taking it earlier in the evening. Also, work on building a calming bedtime routine. And if melatonin still isn’t working well for you, don’t worry—you can stop taking it at any time.
Want to try something else? Look into magnesium supplements—they’re also natural and may help you sleep better without the side effects.