NyQuil by Vicks is a line of cold and flu medications formulated to be used at night. NyQuil contains a blend of ingredients to help relieve symptoms that can make it difficult to sleep. Several ingredients in NyQuil can also induce sleepiness.

There are several important points to consider before using NyQuil to help get to sleep. We discuss whether NyQuil can be used as a sleep aid and why it should not be used long-term. We also explore other ways to improve sleep and when to talk to a doctor.

Why Does NyQuil Make You Sleepy?

In addition to relieving cold and flu symptoms that keep people awake, NyQuil also contains medications that can make people feel sleepy.

NyQuil is available in liquid-filled capsules, in liquid form, or as a powder to add to a cup of hot water. There are many specialized versions of NyQuil, including alcohol-free and sugar-free varieties, formulations specifically for children or people with high blood pressure, and versions with added ingredients that target coughing or nasal congestion.

Most formulations of NyQuil contain three active ingredients: doxylamine succinate, dextromethorphan, and acetaminophen. Both doxylamine succinate and dextromethorphan have the potential to cause drowsiness.

Doxylamine Succinate 

Doxylamine succinate is included in NyQuil to treat nasal symptoms, such as sneezing or a runny nose. This medication is an antihistamine found in a variety of over-the-counter cold and flu medications. 

Doxylamine works by blocking the activity of histamine throughout the body. Histamine is produced by the immune system to help combat infections, and it also helps the body stay awake. By blocking histamine in the body, antihistamines can make a person feel tired .


Dextromethorphan is a cough suppressant used in a wide range of medications that treat coughing. Rather than addressing the underlying cause of coughing, it works by slowing down activity in the brain that triggers the body to cough . While not intended to be a standalone sleep aid, dextromethorphan can cause drowsiness as a side effect.


Also branded as Tylenol when sold on its own, acetaminophen is a common pain reliever that is included in NyQuil to relieve discomfort from headaches and sore throats. Acetaminophen is not known to cause drowsiness.

How Soon Do You Feel Sleepy After Taking NyQuil?

NyQuil usually triggers sleepiness approximately half an hour after a person takes the medication. Doctors may recommend waiting to take the medication until just before bedtime , as it can take a full night for the effects to wear off. Since NyQuil causes drowsiness, it is unsafe to drive or perform other potentially dangerous activities until the effects of the medication have fully worn off. 

Should You Take Nyquil for Sleep?

NyQuil is not designed to be taken as a sleep aid, or for any purpose besides relieving cold or flu symptoms. 

Although doxylamine is an approved sleep aid when sold on its own, this sleep-inducing ingredient should generally not be used for more than two weeks. Doxylamine may become less effective for people who take it regularly, who then may need higher doses to feel its effects. Any use longer than two weeks should only occur under the guidance of a doctor.

It is also not recommended to take other ingredients in Nyquil, like acetaminophen and dextromethorphan, more often than recommended. The active ingredients in NyQuil can be dangerous when taken in excess. They may also cause side effects such as dizziness, dry mouth, headaches, and skin rashes. 

Taking too much acetaminophen or combining NyQuil with other drugs containing acetaminophen may cause serious liver damage. Additionally, a person should not take NyQuil at the same time as a wide range of other medications. Before combining medications, people should read the NyQuil label carefully and consult with a health professional.

Experts also recommend that adults over 65 avoid NyQuil, as they may be more sensitive to side effects such as confusion and dry mouth. Those who are pregnant, breastfeeding, or have coexisting medical conditions should also consult with a doctor before taking NyQuil. 

What Are Other Ways to Improve Sleep?

Sleep experts have identified a number of sleep hygiene tips for getting better rest. These ways to improve sleep include both daytime habits and bedtime rituals.

  • Keep the bedroom cool, dark, and quiet: Turn off electronic devices in the bedroom and consider using blackout curtains or a white noise machine to block out distractions.
  • Stick to a regular bedtime: To keep the body on a healthy sleep schedule, try to keep a consistent bedtime every day of the week.
  • Create a bedtime routine: Calm, relaxing activities can help the brain wind down for sleep. Good activities for a bedtime routine include listening to music, reading a book, or taking a hot bath.
  • Avoid caffeine, alcohol, and nicotine at night: These substances can make it difficult to sleep soundly and may wake you up at night.
  • Exercise regularly: Regular exercise and spending time outside can help with healthy sleep, but try to avoid extra-vigorous exercise in the leadup to bedtime.
  • Nap mindfully: While naps can boost energy, taking long naps or napping later in the day can interfere with nighttime sleep.
  • Do not lie awake in bed: Watching the clock or spending too long in bed awake can increase anxiety and make it harder to get to sleep.
  • Avoid blue light: Limit your exposure to blue light from televisions, cell phones, tablets, or computer screens a few hours before bedtime. 

Though doctors often recommend starting with improvements to sleep hygiene, many over-the-counter and prescription sleep aids are also available. Experts recommend consulting with a doctor before taking any drug or supplement, even those that are available over the counter.

When to See a Doctor

Talk to a doctor if you have persistent insomnia, frequently sleep poorly, or often wake up feeling unrefreshed. You should also talk to a doctor if your cold and flu symptoms persist, or if you develop side effects such as dizziness or nausea.

If lifestyle changes are not enough to improve your sleep, an underlying sleep disorder or other health condition may be to blame. Your health care provider can help determine the causes behind your sleep issues and develop a treatment plan to get you more much-needed rest.

Learn more about our Editorial Team

5 Sources

  1. Brott, N. R. & Reddivari, A. K. R. (2022, June 11). Doxylamine. In StatPearls. StatPearls Publishing., Retrieved March 31, 2023, from

  2. AHFS Patient Medication Information. (2022, January 15). Dextromethorphan. American Society of Health-System Pharmacists, Inc., Retrieved March 31, 2023, from

  3. Lexicomp. Doxylamine: Drug information. UpToDate., Retrieved March 31, 2023, from

  4. Lexicomp. Acetaminophen (paracetamol), dextromethorphan, and doxylamine: Drug information. UpToDate., Retrieved March 31, 2023, from

  5. National Heart, Lung, and Blood Institute. (2011, August). Your guide to healthy sleep., Retrieved March 31, 2023, from


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