ZzzQuil vs Benadryl

ZzzQuil vs Benadryl: Are They the Same Thing? [Differences]

My mother sometimes has trouble falling or staying asleep. Like many others, she relies on a sleep aid to get some rest. Recently, my mom asked me if I know the difference between ZzzQuil and Benadryl and if one is better than the other. So, I did extensive research which I would now like to share with my readers. Here’s what I found out.

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Since both ZzzQuil and Benadryl have diphenhydramine as their active ingredient, they are very similar in terms of their effectivity, safety, and side effects. They are also both readily available even without prescription. The only difference between these two is that ZzzQuil is marketed as a sleep aid. As such, Benadryl is the more economic choice though ZzzQuil is still quite affordable.

Benadryl Ultratabs Antihistamine Allergy Relief is a must try if you’re looking for something to help with your insomnia. You get the exact same benefits that you can get from ZzzQuil but for less money. It even offers allergy relief which is a great bonus if you suffer from allergies. But if you’re allergic to some of Benadryl’s ingredients or you can’t take it for some reason, check out ZzzQuil Nighttime Sleep Aid LiquiCaps which has the same active ingredient. While it doesn’t offer allergy relief, it takes effect slightly faster than Benadryl.

sleep aid comparison table

ZzzQuil vs Benadryl Comparison Table

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What Is ZzzQuil and What Is It Used for?

are ZzzQuil Benadryl same thing

ZzzQuil is a product that is manufactured by the brand Vicks which is owned by Procter & Gamble, an American company. It is an over-the-counter sleep aid that is available in either a liquid or liquid-filled gel capsule form.

It is used for insomnia, a sleep disorder that makes it hard to fall or stay asleep. However, it shouldn’t be used for more than two weeks.


The active ingredient of ZzzQuil is diphenhydramine, an antihistamine that is used to relieve allergies. Inactive ingredients include the following:

  • sorbitol sorbitan solution
  • purified water
  • polyethylene glycol
  • pharmaceutical ink
  • glycerin
  • gelatin
  • FD&C Red No. 40
  • FD&C Blue No. 1

There’s also 10 percent alcohol in both ZzzQuil Calming Vanilla Cherry Liquid and ZzzQuil Warming Berry Liquid. So, if for some reason you can’t have alcohol, you’ll want to use the non-alcoholic versions which are the ZzzQuil LiquiCaps and ZzzQuil Alcohol-Free Liquid.

What Is Benadryl and What Is It Used for?

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Benadryl is a brand name for a range of antihistamines that are used to relieve allergies, hay fever, and the common cold. These are manufactured by Johnson & Johnson and can be bought without a prescription.

The topical versions can be used to relieve rashes and itchy skin caused by allergies while the oral form can be taken to help with allergy symptoms like watery eyes, runny nose, cough, and sneezing. However, due to the active ingredient in Benadryl, it is also often used by people with sleep problems.


The active ingredient of Benadryl is diphenhydramine. For its inactive ingredients, it has the following:

  • talc
  • titanium dioxide
  • stearic acid
  • starch
  • pregelatinized starch
  • providone
  • polyethylene glycol
  • microcrystalline cellulose
  • hypromellose
  • crospovidone
  • colloidal silicone dioxide
  • candelilla wax


How Can Diphenhydramine Help with Your Insomnia?

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Both ZzzQuil and Benadryl have the same active ingredient, which is diphenhydramine. This blocks the histamine that our body produces when there’s an allergen. It is what’s responsible for the sneezing and itching that you experience when you get an allergic reaction.

One of the side effects of diphenhydramine is drowsiness. Therefore, it is often used by people with insomnia. In fact, there are studies that suggest that people fall asleep faster and longer when they take diphenhydramine.

Are ZzzQuil and Benadryl the Same Thing?

ZzzQuil and Benadryl aren’t exactly the same thing. However, they both contain diphenhydramine and are used as a sleep aid.

What Are the Differences Between ZzzQuil and Benadryl?


Though ZzzQuil and Benadryl have the same active ingredient, they differ in their inactive components. This is why even though ZzzQuil has diphenhydramine, it isn’t really used for allergies.

Dosage and Effectivity


ZzzQuil Nighttime Sleep Aid-LiquiCaps

ZzzQuil should only be taken once a day, before bedtime. Occasional use is advised, and it should not be taken continuously for more than two weeks. How long the effects of this sleep aid will last depend on several factors. As such, it is recommended that you only take it when you have enough time to get adequate sleep. Otherwise, you might feel groggy when you wake up.


The maximum dosage that you can take to use Benadryl as a sleep aid is 50 mg. This dose will then take effect within an hour and will stay active for four to six hours.

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Side Effects and Safety


This sleep aid is safe for occasional use. However, if you want to take it for more than two weeks, you’ll want to consult with your doctor first. Though it isn’t habit-forming, there’s a chance that you’ll become dependent on it after a long period of use which is why it should only be taken occasionally.

You might experience some side effects with ZzzQuil if you’re taking higher doses or not getting enough sleep after taking it. This includes 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


Also, just like with any medication, there’s a chance that you develop adverse reactions to the drug. Potential serious side effects include:

  • 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


If you’re taking any medication or have any medical conditions, you must check with your doctor first before you start using this sleep aid. The same goes if you’re pregnant or breastfeeding.

You also cannot take ZzzQuil with alcohol since it can cause overdose and serious complications. Finally, it’s not advisable to give it to children under 12 years old as well.

Benadryl Antihistamine Allergy Relief

Since Benadryl and ZzzQuil have the same active ingredient, they’re mostly the same in terms of safety and side effects. Though you can get it without a prescription, it’s still best to consult with your healthcare provider to get a dosage that is just right for you. This is especially true if you’re taking medications which can interact with the sleep aid or if you have any medical conditions.

Some of the common side effects of this over-the-counter antihistamine include the following:

  • dry mouth
  • vomiting
  • blurred vision
  • stomach upset
  • drowsiness


There are also serious side effects like the following which you need to watch out for.

  • anxiety
  • nausea
  • constipation
  • rapid heart rhythm
  • painful urination
  • difficulty urinating


Alcohol should never be taken with antihistamines since it can heighten its effects which might lead to complications. Also, just like with any sleep aid, you shouldn’t drive or operate any machinery after taking Benadryl. This is a common mistake since Benadryl isn’t labeled outright as a sleep aid.

While it is considered safe to take Benadryl when you’re pregnant, it’s still best to consult with your doctor. On the other hand, if you are lactating, it’s best to not use this antihistamine as it can pass through your breastmilk.

Likewise, it should never be given to given to children unless advised by your pediatrician.

ZzzQuil Nighttime Sleep Aid LiquiCaps

Brief Review

ZzzQuil Nighttime Sleep Aid LiquiCaps is one of the most popular products in Vicks’ ZzzQuil lineup. It takes effect in just 20 minutes so you can get refreshing sleep soon after taking it. Plus, it is non-habit forming so you can use it without any worries. 

See the price and read real reviews

Benadryl Ultratabs Antihistamine Allergy Relief

Brief Review

You’ll also want to check out the Benadryl Ultratabs Antihistamine Allergy Relief, a highly-rated antihistamine which doubles as a sleep aid. It’s a good product to have on hand since it can both help you with your allergy symptoms and when you’re having trouble falling asleep.

See the price and read real reviews

Pros and Cons of ZzzQuil and Benadryl



  • Available over-the-counter and can be purchased in leading physical and online stores
  • Very effective in inducing drowsiness and decreasing alertness
  • Can be quickly absorbed by the body
  • Available in various forms like liquid and capsule



  • Can cause dependence if used too often
  • Doesn’t help with the real issue of the sleep disorder
  • Potential side effects
  • More expensive than Benadryl




  • Cheaper
  • Available over-the-counter and can be bought in physical stores or via the Internet
  • Very effective in inducing sleepiness and blocking alertness
  • Different forms available to suit user preference
  • Fast-absorbing



  • There’s a risk of developing various side effects
  • Less effective when taken too often
  • Doesn’t address the cause of the sleep problem


sleeping pills side effects

Related: Melatonin vs Diphenhydramine (Benadryl)


So, are ZzzQuil and Benadryl the same thing?

To put it simply, there’s almost no difference between ZzzQuil and Benadryl since their main active ingredient, diphenhydramine, is the same. They are very similar in terms of their effectivity, side effects, safety and availability. The only real difference is that Benadryl is cheaper, and it is always handy to have an antihistamine for when your allergy suddenly comes up.

However, I’d like to give a simple reminder that sleep aids like ZzzQuil and Benadryl should only be taken occasionally. If your body gets used to getting help in falling asleep, you’ll have a more difficult time getting some rest. You’ll also develop a tolerance to the product which means that you’ll need to take a higher dosage to feel its effects, putting you at a higher risk of developing side effects.

If you find that you still have a hard time falling or staying asleep after two weeks of using either Benadryl or ZzzQuil, consult your doctor. It would be good to explore more natural options or even better, to address the root of your insomnia.