ZzzQuil vs NyQuil: Which Gets You Better Sleep?

My wife and I have had a rough stretch of late. With our newborn baby finally home, sleep has come few and far in between. It has gotten so bad that at times, I would find myself at a specific aisle of the grocery store and completely forget what I was there for!

ZzzQuil vs NyQuil

REM [/rɛm/] noun
The stage in the sleep cycle when dreams occur. Also a famous band.

I shared my predicament with a few friends and I was surprised to hear them recommend that I take NyQuil to get some shut-eye. I’ve only ever taken NyQuil when I was suffering from a cough, cold or flu. I was also well aware that the company that makes NyQuil actually has a different range of products that they make specifically for sleep. And so, I began to wonder which one between ZzzQuil and NyQuil should I take.

I did a fair amount of research, which helped open my eyes to what these two products are really all about. If you’re in the same position that I was, it’s best you take the time to read this handy, helpful guide that takes a stab at the ZzzQuil vs. NyQuil comparison.

Let’s first discuss what is ZzzQuil and what is it used for?

Table of Contents

This is a loooong guide. Here’s a handy list of topics. Click on one if you don’t want to read the whole thing 🙂

  1. ZzzQuil – What? How? Side Effects? Precautions?
  2. NyQuil – What? How? Side Effects? Precautions?
  3. What Are the Primary Differences Between ZzzQuil and NyQuil?
  4. Pros and Cons of ZzzQuil and NyQuil
  5. What are Other Sleep Medications That You Can Try?
  6. The Bottom Line

What is ZzzQuil?

ZzzQuil is an over-the-counter nighttime sleep aid that can be bought without any prescription at most drug stores. The active ingredient in ZzzQuil is diphenhydramine, which is also the active ingredient in the allergy medication Benadryl.

Diphenhydramine is an antihistamine that people often use to help them deal with allergic reactions, itchiness, and hives. The most common side effect of diphenhydramine is drowsiness.

ZzzQuil is considered to be a safe and effective medication for helping you deal with short-term sleeping difficulties, or insomnia, in people over 12 years old. However, individuals with specific medical conditions, like asthma and heart disease, should consult with a doctor before taking ZzzQuil.

ZzzQuil vs NyQuil Comparison

What is ZzzQuil Used For?

A person should use ZzzQuil as a short-term relief for problems with sleep.

The active ingredient in ZzzQuil is an antihistamine called diphenhydramine.

Antihistamines diminish the effect of histamines, which are natural chemicals that the body generates during an allergic reaction.

Diphenhydramine binds to the histamine-1 receptor in the body. This receptor can be found in many areas of the body, which include the respiratory tract, abdominal tract, immune cells, and brain. Antihistamines such as diphenhydramine are common ingredients in allergy and cold medications.

The most noted side effect of diphenhydramine is drowsiness, which is because of the effect that some antihistamines can have on the brain. It is strongly recommended by the manufacturer that ZzzQuil is used just for relieving occasional sleeplessness. ZzzQuil works by helping to lessen the time it takes for a person to fall asleep.

How to take ZzzQuil

Adolescents and adults can make use of ZzzQuil as short-term help for occasional problems getting to sleep. The manufacturer strongly recommends that children below 12 years of age should not use this medication.

The recommended dose of ZzzQuil is 50 mg at bedtime when needed, or as a person’s doctor directs. ZzzQuil can be bought in both liquid and capsule forms.

For the liquid form, a single 50-milligram dose is equal to 30 milliliters, or 2 tablespoons. Liquid ZzzQuil comes with a special cup for measuring out the correct dose.

For the capsule form, a single 50 mg dose is equal to two ZzzQuil capsules. A person cannot cut, chew, or split the capsules. People should not take more than 50 mg of ZzzQuil in a single day.

The liquid form of ZzzQuil has 10% alcohol. ZzzQuil is also available in an alcohol-free liquid solution, which may be more appropriate for adolescents.

What are the Side Effects?

The side effects of diphenhydramine can include headaches and drowsiness.

Diphenhydramine, which is the active ingredient in ZzzQuil, can cause side effects in some people.

The most common side effects of diphenhydramine include:

  • drowsiness
  • dizziness
  • loss of coordination
  • headaches
  • upper abdominal pain
  • thickened mucus in the lungs
  • dry mouth and nasal passages
  • stimulation of the central nervous system
  • constipation
  • euphoria
  • involuntary muscle movements
  • painful or difficult urination
  • low blood pressure
  • blurred or double vision
  • irregular heartbeat
  • sensitivity to light
  • erectile dysfunction
  • early periods
  • anorexia

Rarely, more serious side effects can occur, including:

  • severe allergic reactions
  • abnormal heart rhythm
  • anemia

What are the Precautions That You Should Know About?

The intended use of ZzzQuil is for occasional sleeplessness. It is strongly recommended that people consult a doctor if they keep on experiencing sleeping difficulties for over 2 weeks, as this may be a symptom of a dire medical condition.

Because ZzzQuil can result in experiencing drowsiness, it may affect a person’s ability to drive or operate heavy machinery. It is also crucial to avoid drinking alcohol when taking ZzzQuil as this can also heighten drowsiness. Older adults should use ZzzQuil with caution as side effects such as drowsiness, dizziness, and low blood pressure can raise the risk of falling.

Taking ZzzQuil may also have the possibility to worsen particular medical conditions, such as:

  • asthma
  • hyperthyroidism
  • heart disease
  • high blood pressure
  • glaucoma

Individuals with these conditions should definitely consult their doctor before taking ZzzQuil.

People who experience urinary difficulties while taking ZzzQuil should also stop taking the medication and speak to a doctor.

Who Should Avoid Taking ZzzQuil?

Not everyone can take ZzzQuil. People should not give ZzzQuil to children under the age of 12 years. The active ingredient of ZzzQuil can pass into breastmilk, so people who are breastfeeding should go see a doctor before taking it. Pregnant women should also seek medical advice before using this medication.

People taking monoamine oxidase inhibitors (MAOIs), which is a type of antidepressant, should also avoid taking ZzzQuil or speak to a doctor first before doing so. MAOIs can heighten some of the side effects of antihistamines.

Although ZzzQuil has diphenhydramine, which can help relieve allergy symptoms, it can still cause allergic reactions in some people. Anyone who has initially had an allergic reaction to ZzzQuil or medicines containing diphenhydramine should avoid taking it.

Is ZzzQuil Addictive?

A person may have worsened sleeplessness because of withdrawal symptoms from a diphenhydramine dependence. According to a review, diphenhydramine is among the list of medications misused by people presenting to the emergency department for drug treatment.

Antihistamines are widely available in OTC medications. The drowsing effect of antihistamines can help relieve sleeplessness and anxiety. Taking too much diphenhydramine can potentially cause a calming effect and mild euphoria. Some people actually misuse diphenhydramine for its hallucinogenic effects, which may occur at doses of 300–700 mg.

Diphenhydramine is not addictive at the suggested dosage. However, taking very large doses of diphenhydramine, such as over 1,000 mg per day, for a prolonged period can lead to dependence. People who become dependent on diphenhydramine can experience withdrawal symptoms when they stop taking it.

These may include:

  • worsened sleeplessness
  • runny nose
  • stomach upset
  • irritability
  • restlessness
  • abdominal cramps
  • sweating
  • diarrhea

Doctors often recommend a gradual dosage reduction schedule for people who have indeed become dependent on diphenhydramine. This specific detox program helps treat a person’s dependence and reduces uncomfortable withdrawal symptoms.

Case reports of adolescents and adults with diphenhydramine dependence highlight how significant it is for doctors to ask about OTC medication use, most especially in people with previous or current addictions and psychotic illnesses.

What is NyQuil?

NyQuil is a combination medication is used to briefly treat symptoms that are caused by the common cold, flu, allergies, or other breathing illnesses like sinusitis, bronchitis. Dextromethorphan is a cough suppressant that impacts a specific part of the brain, reducing the urge to cough.

What Are the Differences Between ZzzQuil and NyQuil?

Decongestants help alleviate stuffy nose and ear congestion symptoms. Acetaminophen (APAP) is a non-aspirin pain reliever and fever reducer. Antihistamines help relieve watery eyes, itchy eyes/nose/throat, runny nose, and sneezing.

This medication is not often used for ongoing coughs from smoking, asthma, or other long-term breathing problems like emphysema, or for coughs with a lot of mucus unless your doctor specifically prescribes it.

Cough-and-cold products have not been proven to be safe or effective in children younger than 6 years. Therefore, it is not recommended that you use this product to treat cold symptoms in children younger than 6 years unless specifically directed by the doctor. Some products like long-acting tablets/capsules are not recommended for use in children younger than 12 years.

How to Use Nyquil Liquid

If you are taking this over-the-counter product, it is important that you read and follow all directions on the package label. If your doctor has prescribed this medication for you, take as directed by your doctor. If you have any questions, never hesitate to consult your doctor or pharmacist.

Take this medication by mouth with or without food or as directed by your doctor. If stomach upset happens, it may help to take this medication with food or milk. Drink plenty of fluids when you utilize this medication unless otherwise directed. The fluid will help loosen the mucus in your lungs.

If you are using the liquid form of this medication, prudently measure the dose with the use of a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. If your liquid form is a suspension, shake the bottle well before each dose.

If you are taking extended-release capsules, swallow them whole. Do not crush or chew extended-release capsules or tablets. Doing this can release all of the drugs at once, thereby raising the risk of side effects. Also, do not split extended-release tablets unless they have a score line and your doctor or pharmacist tells you to do so. Swallow the whole or split tablet without crushing or chewing.

If you are taking the chewable form of this medication, chew it thoroughly before swallowing.

The dosage is based on your age, medical condition, and response to treatment. Do not increase your dose, take it more frequently, or use it for a longer time than directed. Improper use of this medication may result in severe harm, which may include brain damage, seizure, death.

Immediately inform your doctor if your condition persists for more than a week, if it worsens, or if it occurs with rash, persistent headache, or fever lasting more than three days. These may be symptoms of a serious medical problem and should be checked by a doctor.

What are the Active Ingredients?

  • Acetaminophen 500mg (pain reliever)
  • Dextromethorphan HBr 15mg (cough suppressant)
  • Doxylamine succinate 6.25mg (antihistamine)

What is the Dosage?

  • Adults – Two tablespoons every 6 hours as needed for cold and flu symptoms. Do not take more than 4 doses in 24 hours.
  • Children – Ask a doctor.

What are the Side Effects?

Drowsiness, dizziness, blurred vision, upset stomach, nausea, nervousness, constipation, or dry mouth/nose/throat may occur. If any of these effects persist or worsen, immediately consult with your doctor or pharmacist.

If your doctor has recommended this medication, remember that he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if any of these unlikely but dire side effects occur:

  • mental/mood changes (such as confusion, hallucinations)
  • shaking
  • trouble urinating

A very serious allergic reaction to this drug is rare. However, immediately seek medical attention if you notice any symptoms of a serious allergic reaction, including:

  • rash, itching/swelling (especially of the face/tongue/throat)
  • severe dizziness
  • trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, it is imperative that you contact your doctor or pharmacist.

Before taking this product, tell your doctor or pharmacist if you are allergic to any of its ingredients; or if you have any other allergies. This product may have inactive ingredients, which can result in allergic reactions or other health concerns. Talk to your pharmacist to gather more information.

If you have any of the following health problems, consult your doctor or pharmacist before using this medication:

  • breathing problems (such as asthma, emphysema)
  • diabetes
  • glaucoma
  • heart problems
  • high blood pressure
  • kidney problems
  • liver disease
  • seizures
  • stomach/intestinal problems (such as blockage, constipation, ulcers)
  • overactive thyroid (hyperthyroidism)
  • urination problems (such as trouble urinating due to an enlarged prostate urinary retention)

This drug may make you dizzy or drowsy or even blur your vision. Alcohol or marijuana (cannabis) can make you even more dizzy or drowsy. Do not drive, use machinery, or do anything that needs you to be alert or has clear vision until you can do it safely. Avoid alcoholic beverages.

Before having surgery, tell your doctor or dentist that you are taking this medication.

Older adults may be more sensitive to the effects of this drug, especially dizziness, drowsiness, mental/mood changes, constipation, trouble urinating, fast heartbeat, and blood pressure changes. Dizziness, drowsiness, and confusion can increase the risk of falling. During pregnancy, this medication should be used only when clearly needed. This medication may pass into breast milk and may have undesirable effects on a nursing infant.

What Are the Primary Differences Between ZzzQuil and NyQuil?

Pros and Cons of ZzzQuil and NyQuil

1) Its Ingredients


The active ingredient of ZzzQuil Liquicaps is diphenhydramine, a specific kind of antihistamine. It blocks the histamine that your body produces during an allergic reaction.

When you have an allergic reaction, you usually get a runny nose and watery eyes which are two symptoms caused by histamines. Hence, diphenhydramine is used to give you immediate allergy relief.

So why is diphenhydramine the active ingredient of ZzzQuil? Well, the usual side effect of diphenhydramine is drowsiness and that is the main reason why ZzzQuil and other diphenhydramine products such as Benadryl are often used by people with insomnia.

There are other ingredients in ZzzQuil. These include the following:

  • FD&C Blue No. 1
  • FD&C Red No. 40
  • Gelatin
  • Glycerin
  • Polyethylene glycol
  • Purified water
  • Sorbitol sorbitan solution
  • Titanium dioxide

Some variations of ZzzQuil also have 10 percent alcohol. But ZzzQuil LiquiCaps and ZzzQuil Alcohol-Free Liquid are non-alcoholic versions, which you can utilize if you are not able to take alcohol.


NyQuil has four active ingredients. These are:

Acetaminophen – Acetaminophen, or what is commonly known as paracetamol. It is a pain reliever and fever reducer

Dextromethorphan (DXM) – This ingredient is a cough suppressant.

Doxylamine – Doxylamine succinate is another kind of antihistamine that can alleviate runny nose and sneezing. Just like diphenhydramine, it can cause drowsiness.

Phenylephrine HCl – It is a nasal decongestant that can offer you temporary relief from a stuffy nose and sinus. It can also diminish swelling in the ears brought by the common cold, flu, and allergies.

Its inactive ingredients are the following:

  • Citric acid
  • D&C Yellow No. 10
  • FD&C Yellow No. 6
  • FD&C Green No. 3
  • Flavor
  • Glycerin
  • Propylene glycol
  • Purified water
  • Saccharin sodium
  • Sodium benzoate
  • Sodium chloride
  • Sodium citrate
  • Sorbitol
  • Sucralose

NyQuil Liquid also has 10 percent alcohol but variations like the NyQuil Liquicaps and Alcohol-Free NyQuil Cold & Flu Nighttime Relief Liquid are alcohol-free.

2) How About the Dosage and Effectiveness?


Adults and children 12 years of age and older can take up to two ZzzQuil LiquiCaps or 30 mL of ZzzQuil Liquid when it’s bedtime. However, as mentioned several times above, it shouldn’t be given to children under 12 years of age.

There are many factors that can affect its effectiveness. However, it is suggested that you only take ZzzQuil when you can get at least eight hours of sleep. Otherwise, you might feel bleary in the morning when you wake up.


Adults and children, 12 years of age or older can take up to two liquicaps or 30 mL of NyQuil Liquid every six hours.

Children that are 6 to 11 years old can take up to 15 mL of Children’s NyQuil every six hours. You should never take more than four doses of NyQuil in a 24-hour period.

As for its effectiveness, it might take about 30 minutes before you can feel its effects.

3) Its Safety


ZzzQuil is relatively safe to take as long as you take note of these reminders:

  • If you are pregnant or breastfeeding, make sure to consult with your doctor first before taking ZzzQuil. This is the same for people who have medical conditions or are taking medication as well.
  • Do not take alcohol together with ZzzQuil since this can result in complications and overdose.
  • Never operate machinery or drive after taking a dose of ZzzQuil.


This product is a great product to alleviate cold and flu. However, there are still some safety guidelines that you need to keep in mind. These are the following:

  • Consult your doctor before taking NyQuil if you are pregnant, lactating, taking medication or have existing medical conditions.
  • Do not take NyQuil if you have just ingested alcohol.
  • Do not take acetaminophen together with NyQuil since this can result in liver damage.
  • Do not take this product if you are taking tranquilizers or sedatives.

Just like ZzzQuil, NyQuil can diminish your mental attentiveness and cause drowsiness. As such, never drive or operate machinery after taking it.

4) Possible Side Effects


If you’re taking ZzzQuil at higher doses or if you’re not getting sufficient sleep after that, there’s a possibility that you’ll develop minor side effects like the following.

  • day-time drowsiness after night-time use
  • loss of coordination
  • blurred vision
  • drowsiness
  • dry eyes
  • upset stomach
  • constipation
  • dry nose, mouth, or throat

There’s also a chance that you’ll experience severe side effects such as:

  • uncontrollable movements of the tongue
  • rapid or irregular heartbeats
  • tightness in the jaw or neck
  • feeling like you might pass out
  • painful urination
  • confusion
  • little or no urinating


Just like any other medication, NyQuil has potential side effects.

  • headache
  • nausea
  • vomiting
  • dizziness
  • lightheadedness
  • stomach pain, diarrhea or constipation
  • dry eyes, nose or mouth
  • drowsiness
  • restlessness
  • nervousness
  • blurred vision
  • mild skin rash

There are grimmer side effects like the following as well:

  • difficulty urinating
  • allergic reaction characterized by hives, itching, swelling, difficulty breathing
  • seizure
  • severe headache
  • hallucinations
  • uneven heartbeat

Pros and Cons of ZzzQuil and NyQuil

To give you a more concise idea of the pros and cons of each product, I’ve listed them all down here for you to check:



  • Can be picked up without a prescription
  • Can be found in leading physical and online stores
  • Effects can be felt right away
  • Very effective as a sleep aid
  • Available in various forms and flavors
  • Non-habit forming


  • Can cause dependence if taken too often
  • Doesn’t target the root of the sleep disorder



  • Very effective in alleviating cold and flu symptoms
  • Can give you relief in as little as 30 minutes
  • Can be bought without a prescription
  • Can be found in most physical and online stores
  • Available in different forms and flavors
  • Will definitely knock you out while your body heals itself


  • Possible side effects

What are Other Sleep Medications That You Can Try?

Alternative to NyQuil DRIFTOFF Premium Sleep Aid

1) DRIFTOFF Premium Sleep Aid

  • Made with an emphasis on natural, non-habit forming ingredients
  • Can help calm anxiety and ease restlessness
  • Helps you wake up feeling refreshed, energized

Price & Reviews

Sounder sleep can now be yours in an instant with the Driftoff Premium Sleep Aid. The vegan and non-GMO formula has melatonin and valerian root, along with other herbal-based elements.

The mix doesn’t just inspire proper sleep, but it also has calming properties to alleviate anxiety, so that you can have a good night’s rest even after a very stressful day.

Alternative to ZzzQuil Stress-Relax by Natural Factors

2) Stress-Relax by Natural Factors

  • Made to support each phase of a refreshing slumber
  • Has Suntheanine L-Theanine, melatonin, and 5-HTP to help reset your sleep cycle
  • Does not have drowsy side effects.

Price & Reviews

Stress, whether caused by work, that frightening stack of bills or even marriage or family troubles, can keep you up well into the night. To help you deal with all that, Stress-Relax Tranquil sleep aid is your answer.

The tropical fruit-flavored chewable tablets feature melatonin and the amino acids suntheanin and 5-HTP, which collaborate to boost relaxation and halt stress for more restful sleep. And because the formula acts immediately, you’ll be off to dreamland in no time.

Alternative to ZzzQuil and NyQuil DREAMRITE Natural Sleep Aid

3) DREAMRITE Natural Sleep Aid

  • Gets you to sleep quickly
  • Wake up feeling refreshed
  • All-natural

Price & Reviews

The Dreamrite Natural Sleep Aid is awesome for those who prefer all-natural sleep solutions. The capsules feature a blend of herbs – including valerian root, chamomile, lemon balm, and passion flower – aside from tryptophan (which is an essential amino acid), magnesium, gaba (a neurotransmitter that helps balance mood and relax the mind) and more.

The Bottom Line

At the end of the day, ZzzQuil is much better for sleep while NyQuil works best as a cough, cold and flu medicine. Since they are made for these intended purposes, you should only use them when the specific situations arise.

This means you should only take NyQuil if you’re sick since it has active ingredients that are utilized to relieve particular symptoms. If you’re looking for a sleep aid that works, then ZzzQuil is your better option.

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