While exploring supplements, it’s almost impossible not to hear about melatonin. It’s everywhere these days—on drugstore shelves, Instagram ads, and memes about vivid dreams. In fact, at this point, the idea that melatonin causes vivid dreams is almost as ubiquitous as the supplement itself.  

In truth, the melatonin can be safe and helpful when taken on occasion, like when you’re trying to kick jet lag or overcome periodic sleep issues—and there technically isn’t a link between melatonin and freaky dreams. But there’s still a how and when to take it. A lot of the time, you might be better off with some sleep help that doesn’t come in tablet form, like meditation.

Here’s what to know about melatonin and the dreams it may or may not cause.

What Is Melatonin?

Melatonin is a naturally secreted hormone National Center for Complementary and Integrative Health “Melatonin: What You Need To Know” View Source that comes from serotonin. It helps regulate circadian rhythms—that is, your biological 24-hour clock. The production of melatonin increases when it gets dark and is limited when it’s light out. This is one of the reasons why your body feels sleepy toward the end of the day.

In almost all cases, the melatonin you get as a dietary supplement is a synthetic version of the natural hormone. It’s generally considered safe for short-term use, but long-term effects are unknown. 

When thinking about what melatonin is, it’s also useful to think about what it isn’t. Melatonin is marketed and packaged as a dietary supplement but it’s not the same thing as a vitamin C or iron tablet. It’s also not a sedative. Although melatonin triggers your brain to get ready for sleep, it’s not guaranteed to keep you asleep for a certain amount of time. For this reason, if you wake up in the middle of the night, taking melatonin may not help you fall back asleep. Even as your body processes the extra melatonin, your natural melatonin is decreasing.

TL;DR: In pretty much every use case, it’s necessary to talk with your physician before trying melatonin. If you have any primary disorder such as obstructive sleep apnea Mayo Clinic “Obstructive Sleep Apnea” View Source (OSA), check with your physician about the appropriate therapy. And if you have acute (that is,  you’ve been dealing with it for less than three months at a time) or chronic insomnia Sleep Foundation “What Are Different Types of Insomnia?” View Source , you should also check with a doctor. Even if you’re only planning on taking it for a short period of time to nudge your circadian rhythm back into action, this will ensure you’re taking it safely.  

If you experience the following, short-term melatonin at the right dose and time might be a good option in combination with other sleep recommendations:

• Jet lag Chronobiology International “The endogenous melatonin (MT) signal facilitates reentrainment of the circadian system to light-induced phase advances by acting upon MT2 receptors” View Source
• Shift work disorder AASM Sleep Education “What Is Shift Work Disorder?” View Source
• Trouble falling asleep

In layman’s terms, supplemental melatonin may help improve sleep quantity and quality PLoS ONE “Meta-Analysis: Melatonin for the Treatment of Primary Sleep Disorders” View Source In theory, the longer you stay asleep, the more times you’ll cycle through the sleep stages. This could include more REM sleep, which is the stage in which vivid dreams often occur Sleep Foundation “What is REM Sleep and How Much Do You Need?” View Source .

Does Melatonin Affect My Dreams?

Melatonin alone doesn’t affect dreams. But because it may indirectly increase the amount of REM sleep The Journal of Clinical Endocrinology & Metabolism “Melatonin in patients with reduced REM sleep duration: two randomized controlled trials” View Source you have during the night, and REM sleep may increase dreams, it can make you feel like you’re dreaming more. Most REM-stage sleep occurs closer to the morning, which is why we often feel we woke up right in the middle of a dream. And because dreams can be wacky enough on their own, just having more of them can be enough to make you feel like melatonin is the direct cause of those dreams where you’re playing table tennis with Sesame Street puppets.

“[The] longer time spent in REM stages means we may spend more time dreaming,” says Rohrscheib. “While the content of the dreams may not be affected, our ability to remember our dreams may be increased.”

Vivid dreams, including nightmares, most often occur when you’re anxious Scientific Reports “Peace of mind and anxiety in the waking state are related to the affective content of dreams” View Source or stressed. If you’re taking melatonin because you’re too stressed to fall asleep, your vivid dreams or even nightmares are more likely to be related to your psychological state than a supplement.

So, that dream you had last night about being naked while presenting your dissertation? Yeah, that’s probably caused by external stress. Melatonin just helped you remember the audience’s faces better. Lucky you.

How Can I Take Melatonin?

Melatonin comes in many forms, including as a gummy, caplet, or liquid—to name just a few. The FDA considers melatonin a dietary supplement and therefore doesn’t have a specific dosage recommendation. 

Luckily, the Sleep Foundation analyzed 16 melatonin studies. Findings suggest that something between 0.5 milligrams to 5 milligrams Sleep Foundation “Melatonin Dosage by Age and Weight” View Source , taken about an hour or two before one’s desired bedtime, appears to be safe and effective for most adults. However, most practicing sleep clinicians suggest a maximum dose of 3 milligrams in most cases.

For older adults, the Sleep Foundation recommends starting with a smaller dose of 0.1 milligrams, because natural melatonin production declines as we age and increasing at a slower pace until the lowest effective dose is achieved. This should be less than 5mg.

For children, an effective dose is less studied. But similar to the elderly, start as low as possible and go slow if you decide to increase, using the lowest effective dose. Melatonin can also cause some side effects in kids, so it’s always best to discuss it with their pediatrician giving it to them. You should also talk with a doctor before taking melatonin if you’re pregnant or breastfeeding.

How to Shop for Melatonin

Most over-the-counter melatonin supplements come in doses of 1, 3, 5, and even 10 milligrams. If you’re taking melatonin for the first time, consider getting the smallest dose you can, then halving or quartering the gummies or tablets.

When shopping for melatonin, look for a pharmaceutical-grade product, like this 3-milligram Douglas Labs option. The pharmaceutical quality should be stated clearly on the label, but if you aren’t sure, run it by your doctor. As a rule of thumb, these will come in bottles that are somewhat bland-looking (at least compared to their flashier, more commercialized counterparts).

Melatonin Side Effects

Because the melatonin hormone occurs naturally in your body, most people don’t experience side effects. However, each person is different, and adverse effects are still a possibility. 

Melatonin isn’t regulated in the same way as prescription and over-the-counter drugs. Plus, labels aren’t always accurate, and doses may deviate between -83% to +478% Journal of Clinical Sleep Medicine “Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content” View Source from what’s on the label. You may also encounter filler products (or low but dangerous levels of other ingredients) in your supplements, so it’s important to start with the lowest possible dose. If you find yourself increasing the dose, it may be time to speak with a doctor. 

Dr. Rohrscheib recommends not exceeding 5 milligrams per day—and even lower for older adults—unless instructed by a doctor. “Melatonin tells your brain the time of day to sleep and be awake. When you introduce high levels of melatonin into your system, you stimulate your circadian rhythm to put you to sleep,” says Rohrscheib.

Other side effects National Center for Complementary and Integrative Health “Melatonin: What You Need To Know” View Source of taking melatonin may include:

• Poor cognitive function
• Headaches
• Dizziness
• Nausea
• Drowsiness
• Anxiety or depression
• Low blood pressure
• Abdominal cramps

Because melatonin flows through your bloodstream, certain medications may be less effective or adversely affected when taken with melatonin. Always avoid alcohol when taking melatonin. Any sedative-hypnotics should be avoided if possible when taking melatonin, too.

Some categories of medications that interact with melatonin are:

• Anti-anxiety and antidepressant medications
• Blood thinning medications
• Blood pressure medications
• Oral contraceptives

If you’re on medication, talk to your physician before introducing melatonin into your bedtime routine.

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