Can a Melatonin Habit Cause Nightmares or Vivid Dreams? Short Answer: Yes

What is melatonin?

As a reminder, melatonin is a naturally occurring hormone that helps govern your circadian rhythm—aka, the body’s sleep-wake cycle—and when the body releases melatonin, it’s a biological signal to hit the hay. In other words, “melatonin in our brains helps us get sleepy,” says clinical psychologist and sleep specialist Shelby Harris, PsyD, author of The Women’s Guide to Overcoming Insomnia. 

How does melatonin work?

To help jump-start the effect, Dr. Harris says folks take melatonin in pill form to help enhance the brain’s natural melatonin and induce sleepiness. The issue, she says, is that oftentimes people take way too much melatonin. Furthermore, experts do warn against nightly use of it, citing reasons like risk of dependence and an overriding of the body's natural response that they don't advise.

“While melatonin has its place in sleep medicine, it is not the panacea many people think it is,” Dr. Harris previously told Well + Good. “Particularly in cases of chronic insomnia, the research on melatonin is actually not largely supportive.”

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What are the pros and cons of using melatonin?

In addition to helping people sleep, Dr. Harris adds that melatonin can also help with jet lag, but the timing of when you take it is very different and tiny dosages are typically used. When using it for this purpose, she recommends working with a specialist.

Dr. Harris also believes melatonin shouldn’t be the first thing people reach for to help kids sleep. Behavioral changes, she says, can help in many cases. However, it isn’t so black and white. “In kids with autism and ADHD, there’s a good deal of evidence that it can be useful as they naturally have lower levels of melatonin,” she says. So to be safe, always consult with a doctor.

Another common question is whether melatonin supplements help decrease depression. “Melatonin isn’t an antidepressant,” Dr. Harris says and therefore not a treatment for depression. “But if you sleep better, sometimes people find they feel better.”

What are the side effects of melatonin?

Dr. Harris says melatonin supplements are commonly linked to other side effects such as nausea, daytime sedation, headaches, and sometimes dizziness. Also, she notes that long-term use of melatonin hasn’t been well studied. So if you’re wondering if there is harm in taking melatonin for longer than a year, her answer is that it’s likely OK. But again, there isn’t consistent research on this to know for sure.

Additionally, Dr. Harris doesn’t recommend mixing melatonin with other sleep aids because it can lead to more risk of sedation in the morning. For this reason, always talk with your doctor before trying out and mixing new things, she says.

Also, taking too much melatonin can increase side effects. “Doses higher than optimal—that is, 5 milligrams at a time—can lead to dizziness, headaches, and nausea, and some people may experience changes in blood pressure, vivid dreams, or nightmares,” behavioral sleep specialist Carleara Weiss, PhD, sleep science advisor for Aeroflow Sleep, previously told Well + Good.

So, how much melatonin is too much?

While there is no official recommendation for adult dosage, experts say .05 to 5 milligrams is safe for adult use, according to the National Sleep Foundation. (Sleep doctor Raj Dasgupta, MD, says he usually prescribes a dose between .05 and 3 milligrams.) Dr. Harris adds that if you typically need more than 3 milligrams of melatonin, it probably isn’t doing anything, or you’re taking too much of it. That said, the range is wide, and the effects will vary from person to person, but if you are experiencing nightmares or bad vivid dreams while taking melatonin, consider taking less or taking a break from the habit in general.

Furthermore, Dr. Dasgupta says to consult a sleep doctor before taking any supplement, whether it's melatonin, valerian root, tryptophan, or chamomile. That includes "what dose, what form, what route, and when," he says. "All of these things are going to be up in the air [regarding how they affect you because none of these dietary supplements are FDA-regulated." Dr. Harris adds that in other countries, a prescription is even required for melatonin.

Does melatonin cause nightmares?

While there’s not much by way of scientific research to make a causal connection between melatonin use and the onset of bad dreams, a 2014 review of studies published in Nutrition Journal found that, though rare, some people have reported having nightmares and more vivid dreams while they were taking the natural sleeping aid. But why?

Dr. Dasgupta says that though he hasn't encountered many reports of melatonin nightmares in his practice, and he certainly wouldn't say a causal relationship exists between the event of taking the supplement and having bad dreams, he can understand why some patients may experience this effect: It has to do, he says, with not just the melatonin, but also what else the person consumed throughout the day.

"It's relative to what else [the person] is taking. That's the problem with talking about nightmares and dreams: It's going to be very subjective," says Dr. Dasgupta. "You have to ask all these other questions, too," he says, referring to whether or not the person drank alcohol, what they might have eaten before bed, and what other supplements they might be taking, because all of these components can also impact dreams.

Dr. Harris adds that other conditions such as PTSD and sleep apnea can also cause nightmares. However, she isn’t aware of a correlation between melatonin and sleep paralysis.

Possible Reasons You May Experience Melatonin Nightmares

One potential reason taking melatonin may lead to having nightmares is not leaving enough time between taking the supplement and actually falling asleep, says Jesse Lyon, a hypnotherapist and dream interpreter. “[Melatonin] doesn't actually help you get into the deeper cycles of REM sleep,” says Lyon. “It's just signaling it's time to go to bed.”

So basically, taking melatonin in supplement form can lead us to shortcut the wake-to-sleep process, which means “your mind doesn't have the appropriate amount of time to vent out the stresses and the anxieties to calm down before bed,” he says. Without the gradual wind-down, he adds, “you're taking those anxieties and stressors with you into your sleep.” And it makes sense that those types of feelings bubbling around in your psyche might lead to vivid or even scary dreams.

“Those who take high levels of melatonin can experience vivid, pretty troubling nightmares because there's not this natural transitory process that's taking place,” says Lyon.

Another possible connection between melatonin and the onset of nightmares caused by melatonin may have to do with dosage. “Those who take high levels of melatonin can experience some pretty vivid, pretty troubling nightmares because there's not this natural sort of transitory process that's taking place,” says Lyon. The higher the dose, that is, the less likely you are to leave enough of that transition time between being awake and being asleep, predisposing you to have those aforementioned busy-mind dreams.

As for types of melatonin nightmares that tend to occur, Lyon says he's noticed several patterns: being chased (whether that’s by monsters or something unknown), house-of-mirrors-style dreams, and deathly scenarios. “All the anxiousness and stress...that's going to manifest as monsters chasing you, being murdered, or running for your life in a house full of mirrors,” he says.

How To Stop Melatonin Nightmares From Compromising Your Sleep

To keep the melatonin-induced bad dreams at bay, Lyon has a few ideas: First, he recommends taking the supplement (after you've cleared doing so with your doctor) one hour before you intended to go to sleep, and at least 20 minutes before you get into bed, so you allow yourself enough time to process the stress of the day before attempting to sleep it off.

Second, he suggests trying to journal as part of the getting-ready-for-bed process. When you journal before bed, you’re “tagging the information that [you] know is important, so [you] can pick it back up in the morning [instead of] bringing it into the bedroom with you.”

Dr. Dasgupta says using a retrospective sleep or dream log can also help you understand whether melatonin could be linked to your bad dreams: "On the nights that you did have these nightmares, describe them. Did you take melatonin? Maybe that piece of information—combined with everything else [what you ate and drank, if you exercised, what other supplements you're taking]—can help you decide, 'Hey, maybe I should stop the melatonin and see what happens.'" Dr. Raj suggests logging all of this information when you wake up in the morning so as to not stress yourself out about tracking your sleep habits. You can also try a bedtime meditation to clear your mind and catch more zzz's without catching the nightmares.