Does Melatonin Cause Nightmares? Why It Can Bring Vivid Dreams, and What Helps
Melatonin can cause vivid dreams or nightmares, but most people who take it never notice a change. Abnormal dreams and nightmares are a known but uncommon side effect: in clinical trials they affected fewer than 1 in 100 people. If they happen to you, the simplest fixes are to take less, to take it earlier in the evening, or both.
When it does happen, people describe dreams that feel longer, brighter and more real than usual, and now and then a bad one that wakes them. Here's what the research says about melatonin and nightmares, the likely reasons it happens, and what to change if your dreams are getting in the way of your sleep.
Does melatonin cause nightmares? What the research says
Yes, but not often. The European Medicines Agency's product information for Circadin, a prescription melatonin tablet sold in Europe, lists "abnormal dreams" and "nightmares" as uncommon side effects, meaning they may affect up to 1 in 100 people. Those figures come from clinical trials of more than 3,500 people, and the label only lists side effects that happened at least as often on melatonin as on a placebo.
Reviews of the research point the same way. A 2019 systematic review of 37 placebo-controlled trials found melatonin's side effects were few and generally mild to moderate. The most common was daytime sleepiness, reported by fewer than 2 in 100 people, followed by headache and dizziness. Only a handful of side effects were judged clinically significant, and nightmares were one of them, alongside agitation, mood swings and fatigue. Most side effects faded within a few days, or as soon as people stopped taking melatonin.
There's one more clue. In the World Health Organization's database of side effect reports, nightmares came up more often for melatonin than for medicines in general, but no more often than for other sleep medicines. Reports like these can't prove cause, but they hint that some of what gets blamed on melatonin comes with sleep aids, or with sleep problems, in general.
Why melatonin can make dreams more vivid
Nobody knows for certain why some people dream more on melatonin. There are three likely explanations, and they can work together.
It may change your REM sleep
Most of the vivid, story-like dreaming you remember happens in REM sleep, the stage when your brain is busy and your body is still. A few small studies suggest melatonin may increase REM sleep. In one trial, 14 people who had unusually little REM sleep took melatonin nightly for four weeks, and the share of their night spent in REM rose from about 15 to 18 percent, while it fell slightly on placebo. But a lab study of 40 older adults found prolonged-release melatonin didn't change the structure of their sleep at all. So this explanation is possible, not proven.
Your longest REM periods come just before you wake
Sleep runs in cycles of roughly 90 minutes. According to the National Institute of Neurological Disorders and Stroke, REM periods get longer and deeper as the night goes on, so the longest ones fall in the last few hours before you wake. If you take melatonin late, or take more than you need, more of it may still be working in those early-morning hours, which is when the most vivid dreams happen anyway.
You may be remembering more dreams, not having more
Everyone dreams every night, and most dreams are forgotten within minutes. You tend to remember a dream when you wake during it or soon after. Research on dream recall backs this up: people who remember lots of dreams spend more time awake during the night, and one study suggests about two minutes awake is enough for a dream to stick in memory. So anything that wakes you in the early hours, from a warm room to a full bladder to a restless partner, makes it more likely you'll wake mid-dream and remember it. Some people also simply pay more attention to their dreams when they start something new for sleep.
Vivid dreams or nightmares?
Melatonin dreams aren't always bad ones. Many people describe them as vivid, long or strange rather than frightening, and some enjoy them. A nightmare is a dream upsetting enough to wake you or stay with you.
If your dreams are just vivid and you wake up rested, there's nothing to fix. If they're waking you, leaving you uneasy in the morning, or making you dread going to bed, it's time to change how you take it.
How to stop melatonin nightmares
- Take less. Vivid dreams are one of the signs your dose may be more than you need, as we explain in is 10 mg of melatonin too much. Cutting a gummy or tablet in half is the simplest first step.
- Take it earlier. One to three hours before bed, rather than as you turn out the light.
- Skip the middle-of-the-night dose. Melatonin taken after waking at 3 am is still working when you need to get up, which can leave you groggy as well as dreaming. How long melatonin lasts explains the timing.
- Give each change a few nights. Judge it over several nights, not one. Dreams vary from night to night anyway.
- Look at the rest of your evening. Stress and anxiety make frightening dreams more likely on their own, according to the National Institute of Neurological Disorders and Stroke, and alcohol, a heavy late meal and some prescription medications can bring on bad dreams too, with or without melatonin.
- Try a few nights without it. If the dreams stop when you stop melatonin, you have your answer. Our guide to sleep gummies without melatonin covers the options for people who'd rather go without.
When to talk to a doctor
- Nightmares that carry on after you stop taking melatonin
- Bad dreams that make you afraid to go to sleep, or leave you tired through the day
- Acting out your dreams: shouting, punching or kicking in your sleep, or falling out of bed. That can be a sign of a sleep disorder and is worth having checked
- Nightmares that started around the time you began a new prescription medication
- A child having nightmares on melatonin. Children should only take melatonin on a doctor's advice
Our sleep gummy
Our Chamomile Sleep Gummies are made in small batches in Holmes County, Ohio. Each Blackberry gummy pairs 10 mg of melatonin with 150 mg of L-theanine, 87 mg of magnesium bisglycinate and 23 mg of chamomile, every amount printed on the jar. If you tend toward vivid dreams, you can cut a gummy in half for about 5 mg, take it an hour or two before bed, and adjust from there by how you sleep and how you feel in the morning. Follow the directions on your jar, and for a step-by-step way to find your amount, see is 10 mg of melatonin too much.
Frequently asked questions
Why does melatonin give me nightmares?
No one knows for sure. The likely reasons are that melatonin may affect REM sleep, the stage when most vivid dreaming happens, and that a dose that's too large or taken too late is still working in the early morning, when REM periods are longest.
Do melatonin nightmares go away?
Usually. In the trials, most of melatonin's side effects faded within a few days or stopped as soon as people stopped taking it, and lowering the amount or taking it earlier is worth trying first. If nightmares carry on after you've stopped melatonin, something else is likely behind them, and it's worth talking to your doctor.
Does melatonin give everyone weird dreams?
No. Most people who take melatonin don't notice any change in their dreams.
Does a higher dose of melatonin cause more nightmares?
No study has tested that directly. Even so, if you're getting vivid dreams, taking a smaller amount, earlier in the evening, is the simplest change to try.
Can melatonin cause night terrors?
Night terrors are different from nightmares. They happen in deep sleep, usually early in the night, and the person rarely remembers them in the morning. They're most common in young children. If your child has night terrors, talk to your pediatrician before giving melatonin or anything else for sleep.
Are vivid dreams on melatonin harmful?
No. Vivid dreams on their own aren't harmful. They only matter if they're disturbing your sleep, and the steps above are the place to start.
What else helps me sleep without bad dreams?
The basics come first: a steady bedtime, a dim, cool bedroom and less alcohol in the evening. Our guide to what actually helps you sleep goes through the options.
These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease. This article is general information and not medical advice. Talk to your healthcare provider before taking melatonin, particularly if you are pregnant or nursing, take prescription medication, or are considering it for a child. If nightmares or trouble sleeping persist, speak to your doctor.