Is it safe

Does melatonin cause vivid dreams?

By GyroscopeUpdated November 14, 20265 sources

People report it a lot, but trials haven’t measured it well. Across 37 trials, nightmares showed up only on the short list of rare side effects. In a 1995 sleep lab test, 0.3 or 1 mg in the evening didn’t suppress REM sleep or push it later. If it happens to you, a smaller, earlier dose is the first thing to try.

Ask around and someone will tell you melatonin gives them movie-length dreams. It’s talked about a lot online and hardly studied, and in the trials dreams rarely made the list of side effects.

We’d take the reports seriously and test it on yourself. Cut the dose, move it 1 to 3 hours before bed, and keep a note by the bed for two weeks, with nights on and off it. If the dreams follow the pill, you’ll see it in your own notes.

There’s also a catch in noticing. Once you’ve heard a pill gives vivid dreams, you may be more likely to remember yours, the way you start seeing your new car’s model everywhere after you buy one.

What the studies show

A 2019 review of 37 placebo-controlled trials, at 0.15 to 12 mg a day, found the most common side effects were daytime sleepiness, headache and dizziness, each in under 2 percent of people. Nightmares appeared among a handful of rarer effects, along with agitation, mood swings and skin irritation.

In 1995, researchers at MIT recorded volunteers’ sleep in a lab after 0.3 or 1 mg at 6, 8 or 9pm. Melatonin shortened the time to fall asleep and didn’t suppress REM sleep or delay its start. Nobody had a hangover the next morning.

Why a big dose might be different

Nobody knows the mechanism. What we do know is how long a dose stays in your blood. A tablet halves about every 54 minutes after its peak, so at 10:30pm, 0.5 mg is back to a normal night level by about midnight, while 10 mg stays above it until somewhere between 3:45 and 6:45am. The bigger the dose, the more of the night it covers, which is a reason to start small, even though no trial has tested it for dreams.

Melatonin in the blood does change how you feel while it’s there. In a 1994 MIT study, every dose from 0.1 to 10 mg made people sleepier and slower on a listening task during the afternoon after.

If the dreams bother you

• Drop to 0.5 to 1 mg.
• Take it 1 to 3 hours before bed, not at lights out.
• Skip it on nights you drink, since alcohol cuts your own melatonin and muddles the test.
• Track it for two weeks, on and off, in the two-week test.

If dreams turn into frequent nightmares that affect your days, stop it and talk to a doctor. Put your dose into the night curve to see how much of your night it covers. Don’t drive after a dose.