Alcohol may well make you feel sleepy when you first climb into bed, they say, but it can affect your quality of sleep later in the night and make you wake up more frequently. The result is that you'll actually get less sleep than if you hadn't had a nightcap.
"A substantial portion of the population uses alcohol on a regular basis to help with sleep problems," says the study's lead author J. Todd Arnedt. "But they may be less aware of the disruptive effects of alcohol on sleep later in the night."
Writing in the journal Alcoholism: Clinical & Experimental Research, the scientists explain that women metabolise alcohol differently to men.
For instance, because women on average have a higher percentage of body fat than men and less water in our systems, we have a higher breath-alcohol concentration after drinking the same amount of booze as men relative to our body weight.
Alcohol is also eliminated from women's bodies faster than men's, they add.
What's your favourite bedtime drink? Are you a hot chocolate fan or do you go for a shot of the hard stuff?