How Alcohol & Melatonin Affect Sleep (+ Why You Should Never Combine Them)

Many people turn to a glass of wine or two to help them relax before bed, as drinking alcohol in moderation has a sedating effect at first. However, as the night goes on, this effect wears off.

"While it can maybe help people fall asleep, it disturbs sleep—especially in the second part of the night. It's not an effective sleep aid to turn to," Fiona Baker, Ph.D., the director of the Human Sleep Research Program at SRI International, says of alcohol.

That's because as alcohol gets metabolized in the night, it disrupts essential deep sleep stages like REM sleep1. Baker adds that it can also increase body temperature and heart rate, contribute to inadequate hydration, and lead us to need to use the bathroom—all things that will further disrupt sleep quality.

Melatonin is an increasingly popular supplement for sleep in the U.S., with recent research showing that demand for it has skyrocketed over the last 20 years.

Like alcohol, melatonin is often used for its relaxing properties to get the body ready for bed. Nicknamed "the hormone of darkness," melatonin is a hormone that gets synthesized in the body when the sun goes down. Using electronics and bright lighting at night, or traveling to a new time zone, can disrupt your natural melatonin production—sending your circadian rhythm, or internal clock, out of whack and causing you to feel wide-awake when you want to be asleep.

Taking supplemental melatonin can help reset your internal clock, making it helpful when you're acclimating to a new sleep-wake schedule. However, there is limited evidence that melatonin supplements improve sleep quality, and it may be dangerous to take nightly—especially in high doses.

It turns out, neither melatonin nor alcohol will do much to improve your sleep quality—especially when combined.

"You want to avoid taking the two together," Rifkin cautions, since alcohol has actually been shown to suppress melatonin levels in the body2. This means that drinking (even in moderation) while on melatonin may disrupt your circadian rhythm and have the opposite effect of what you want.

Besides canceling each other out in a way, Rifkin adds that "they both have a sedating effect, so taking the two together could be dangerous." He notes that the combination can lead to dizziness and overwhelming fatigue, plus further sleep fragmentation.

If you're looking to improve sleep quality, lasting lifestyle shifts will be safer and more effective than short-term fixes (that don't even fix much, anyway) like melatonin and alcohol.

Other habits to get into for better sleep include not eating or exercising late at night, keeping your bedroom cool, dark, and quiet, and releasing stress before bed through practices like journaling or meditation. If you do drink alcohol, experts recommend limiting it to a few drinks at least four to six hours before bed if you can.

There are also plenty of sleep aids that can replace your melatonin habit and do more to actually improve sleep quality.* Here is mbg's list of the best nonhormonal options (we're partial to our melatonin-free sleep support+ supplement, which contains magnesium bisglycinate, jujube, and PharmaGABA®).