Although a few drinks will probably help you fall asleep faster, do not confuse that with alcohol helping you sleep better. In fact, the opposite is true. Alcohol disrupts sleep phases and can leave you with a fragmented or interrupted sleep in the second half of your night. Initially alcohol has a sedating effect but as your body metabolizes the alcohol, it has an activation effect.
Here is how it works:
In the first half of your sleep, as the alcohol is still working through your bloodstream you will sleep very deeply and dreamlessly. This is due to the calming and numbing effect alcohol has on the brain and nerve cells. Alcohol also suppresses rapid eye movement, which is a stage of sleep where most of the dreams happen.
In the second half of the night as the alcohol levels drop, your brain kicks into overdrive. Your body may toss and turn and you will get issues with sleep fragmentation. You will have more vivid and stressful dreams and because you are waking up more frequently, you will remember the dreams more.
Alcohol is also a diuretic, which results in increased urine output and the need to get up and go to the bathroom more frequently.
Alcohol can also effect snoring. Many people snore more after they drink. This is due to the alcohol relaxing the muscles in the upper airway and disturbing normal breathing. This can be especially dangerous with people suffering from sleep apnea.
Some people try to offset the effects of alcohol by taking sleep aids such as Tylenol PM, Benadryl, or melatonin. You should not do this because alcohol is a sedative and it is not wise to use another sedative on top of the alcohol.
If you think that the consumption of alcohol is having an effect on your sleep, the best way to confirm that is to take two weeks off from drinking alcohol and see how your sleep changes.
Once you have determined how the alcohol is effecting your sleep, you can try incorporating a buffer zone on the nights you have a few drinks. Consider having your last drink at least two hours before bedtime. A nightcap is definitely not a good idea.
Keep in mind that alcohol can affect your morning routine. Not sleeping well will make it hard to function properly in the morning, leading some people to reach for more caffeine or other stimulants. This turns into a vicious circle as the use of stimulants can affect sleep as well.