Studies have shown that melatonin supplements can improve sleep quality and sleep time. But there’s no conclusive evidence on how these supplements might affect your dreams.

Melatonin is a hormone that your body makes naturally in your pineal gland. The pineal gland is a tiny, round organ in the center of your brain that’s responsible for using a hormone called serotonin to help regulate your sleep cycle.

Melatonin is synthesized in your endocrine system from serotonin and is a key hormone associated with your circadian rhythm, which helps you fall asleep and wake up every day.

Melatonin’s also been advertised as a sleep aid in supplement form, claiming to help you fall asleep at night.

Your body makes melatonin on its own, so the research isn’t entirely conclusive on whether taking extra melatonin does anything to help you sleep.

But other research has pointed to a fascinating side effect of melatonin: weird, vivid dreams that you may not otherwise have without the extra boost of melatonin before bed.

Let’s get into what the research says about melatonin and dreams, whether it can make you have nightmares, and what’s happening in your brain when you experience this and other side effects of melatonin supplements.

Before we jump into this part, it’s worth discussing a study that suggests the exact opposite: that melatonin can actually be a treatment for people who experience distressing hallucinations at night.


A 2018 study looked at the cases of several people who reported having frightening visions and hearing things at night that would disappear when the lights came on.

The researchers found that taking 5 milligrams (mg) of melatonin worked immediately. Also, 5 mg of delayed-released melatonin helped reduce the number of times these people experienced hallucinations.

And even more interestingly, taking any less than 5 mg had almost no effect on reducing hallucinations, suggesting that 5 mg was a crucial amount for combating the effects of these night terrors.

Vivid dreams

So yes, some research shows that melatonin can have the opposite effect — making vivid dreams or visions at night less likely.

But can melatonin also make your dreams more vivid?

Memory processing

A seminal 1987 study looked at how melatonin is involved in the brain’s processes of storing and erasing recent memories.

The study found that when you’re in rapid eye movement (REM) sleep, melatonin releases a substance called vasotocin, which helps your brain erase memories while you’re dreaming.

It’s during this time of your sleep cycle when you have the kinds of vivid dreams you remember most. Taking extra melatonin can boost the amount of vasotocin that’s let loose in your brain, leading to longer periods of memory-erasing sleep that leave you with intense dreams.

A 1998 study found some evidence for the role of melatonin’s influence on dreams by looking at people with schizophrenia whose brains had problems in these memory systems.

The typical brain erases dream memories as soon as you’re awake so that your brain can tell the difference between dream memories and real memories. But in the brain of someone with schizophrenia, vasotocin isn’t always properly released by melatonin during sleep.

This means that memories of dreams aren’t erased when you wake up, weakening the brain’s ability to distinguish between memories that you experience while awake and those you remember from dreams.

So melatonin may be intimately involved in the whole process of dreaming as a way for your brain to store, erase, and understand memories.

That means any change in melatonin levels — from taking supplements or being deficient because of a mental health condition — can impact the vividness of your dreams.

Sleep quality

Other studies support this idea of melatonin leading to more episodes in your sleep cycle where you have the opportunity to have vivid dreams.

For instance, a 2013 meta-analysis looked at 19 different studies consisting of 1,683 people researching the effects of melatonin on sleep quality, specifically in people with insomnia.

They found that melatonin improved sleep quality, increased total sleep time, and decreased the amount of time it took to fall asleep.

A 2012 study also found that melatonin could help with jet lag by syncing your internal body clock with a new time zone.

People who experience these conditions often report that they don’t remember dreams because of reduced REM sleep, and the extra melatonin may give people more opportunities to have dream-rich REM sleep.

Other health conditions

A 2018 study found an even more intriguing interaction between melatonin and sleep in people with Alzheimer’s disease, as well as other conditions like autism spectrum disorder, insomnia, and high blood pressure during sleep.

The study found that dips of melatonin released at night in people with Alzheimer’s and these other conditions interfered with the sleep cycle and made symptoms more severe and disruptive in their daily lives.

But taking extra melatonin could help combat these symptoms by supporting the physical structures in the brain involved in promoting a natural rhythm in the sleep cycle, resulting in more opportunities for REM sleep and vivid dreams.

Further research will be needed to confirm these results.

There’s much less research to suggest how melatonin can affect how often you have nightmares when you take extra melatonin.

A 2015 case report first found a possible link between melatonin and episodes of nightmares — though taking melatonin itself wasn’t necessarily the source of the nightmares.

This report looked at the case of a person with insomnia who started taking a medication called ramelteon, which interacts directly with receptors in the brain that allows melatonin to promote your natural sleep cycle.

Soon after taking ramelteon, the person reported having intense nightmares. The nightmares stopped almost immediately after their doctor told them to stop taking ramelteon.

This case suggests that melatonin is directly involved in processes that control whether you have dreams or nightmares during REM sleep. The study admits that the exact reason for this link isn’t clear, and that more research needs to be done to explain why this happens.

It’s not exactly clear why the levels of melatonin in your body have a direct effect on how often you dream and how vivid or intense those dreams are.


The release of vasotocin from melatonin during sleep may be a factor here.

Vasotocin is directly involved in regulating REM sleep, and increased amounts of melatonin may influence how much vasotocin gets into your body.

As a result, it may affect how deeply you sleep and how much you dream.

Memory processing

Dreams themselves result from melatonin and vasotocin’s role in helping your brain make sense of your memories. The more melatonin in your body, the more it may be contributing to memory processes happening during sleep.

Because of this, you may have more episodes of vivid dreams that help your brain establish how these memories relate to your understanding of reality while you’re awake.

There’s not a lot of evidence that taking melatonin, even at high levels, causes any harmful, dangerous, or long-term side effects. But some side effects have been documented.

One of the most common side effects of taking melatonin is feeling sleepy during the day.

Daytime sleepiness isn’t really a side effect of melatonin in the truest sense because this means that the supplement is doing its job. Melatonin can help you sleep better at night, but the extra melatonin can continue to make you sleepy throughout the day.

Other reported side effects worth considering before taking melatonin include:

  • headaches
  • dizziness
  • nausea
  • depression
  • shaking in your hands
  • anxiety
  • abdominal cramps
  • irritability
  • feeling less alert
  • feeling confused or disoriented
  • low blood pressure
  • a mild drop in body temperature that can make it hard to stay warm

Melatonin may also interact with other medications, especially sleeping pills, which can affect your memory and your muscle response while doing tasks like driving.

It may also thin your blood, which can increase the effects of blood thinners like warfarin.

There’s no conclusive evidence as to how exactly your dreams are affected by taking melatonin supplements.

But there’s a strong link between melatonin and the vasotocin it releases while you sleep, which allows you to dream and organize your memories.

So it’s not an accident if you notice any changes in your dreams after you start taking melatonin or any medications that affect how your body produces or processes melatonin.