It looks like a cocktail, it is served in a wine glass, and it has been all over social media under a name that made it impossible to ignore: the “sleepy girl mocktail.” Millions of people have tried it in the hope of falling asleep faster. The recipe is simple, the promise is big, and the science behind it is more interesting, and more nuanced, than the videos suggest.
What is in the mix?
The classic version combines three ingredients: tart cherry juice, a magnesium powder and sparkling water or a soda, usually served over ice an hour or two before bed. Each ingredient has its own reason to be there, but two of them do the real work.
What does tart cherry juice do?
Tart cherries, especially the Montmorency and Jerte Valley varieties, naturally contain small amounts of melatonin, the hormone that signals to the body that it is time to sleep. According to an analysis published by The Conversation, clinical trials have found that tart cherry juice can improve sleep quality and quantity and ease insomnia symptoms compared with a placebo.
One small pilot study from Louisiana State University, presented in 2014, followed seven older adults with insomnia, average age 68. When they drank 8 ounces of Montmorency tart cherry juice twice a day for two weeks, they slept about 84 minutes longer per night than with a placebo, according to Nutrition Insight. The sample was tiny, so the result is promising rather than conclusive.
And the magnesium?
Magnesium helps muscles relax and increases the activity of GABA, a neurotransmitter that calms the nervous system. “Magnesium is one of the most important minerals you could have,” clinical psychologist Michael Breus told Scientific American. Studies estimate that 10 to 30% of people in developed countries are deficient.
For sleep, dietitian Claire Rifkin recommends magnesium glycinate, which the gut tends to absorb well, rather than citrate, which can act as a laxative. She advises staying under 350 milligrams of supplemental magnesium a day to avoid cramps, nausea or diarrhea.
So what do sleep experts really think?
They are more measured than the internet. “You might feel a little benefit, but don’t expect a miracle treatment,” said Dr. Thomas Kilkenny, director of the Institute of Sleep Medicine at Staten Island University Hospital, in the same Scientific American piece. In his view, any real effect probably comes from the magnesium, and the cherry juice is there mostly for taste.
The Conversation’s analysis is slightly more optimistic: “Overall, there is evidence to support trying out the Sleepy Girl Mocktail to see if it improves sleep,” it concludes, with a few conditions.
How to try it the smart way
- Choose unsweetened tart cherry juice and plain sparkling water: sugar in the evening can work against sleep.
- Drink it about two hours before bed, then stop drinking, so you are not woken up by a full bladder.
- Watch the magnesium dose, and talk to your doctor first if you take medication or have kidney problems.
- Do not expect it to fix everything. A cool room helps too, which is why people who sleep in a cold room under a heavy blanket are onto something. And if you keep waking up at the same time, sleep doctors say it usually means one of three things.
The bottom line
Mixing tart cherry juice and magnesium will not knock anyone out, and it is no substitute for good sleep habits or medical advice. But both ingredients have a plausible, partly studied effect on sleep, and as bedtime rituals go, a glass of something red and calming is a lot more pleasant than scrolling until midnight.
