A nightcap may make you sleepy at first, but you’ll sleep less soundly and wake up more tired as a result. Alcohol and other depressants suppress a phase of sleeping called REM (Rapid Eye Movement) where most of your dreaming occurs. Less REM is associated with more night awakenings and restless sleep. One glass of wine with dinner probably won’t hurt; however, avoid drinking any alcohol within two hours of bedtime and never mix alcohol with sleeping pills!