What Is The Difference Between Benadryl And ZzzQuil?

In our latest question and answer, the pharmacist discusses the differences between Benadryl and ZzzQuil.

3 min read Updated Jun 2026 Read by 29,258 people
What Is The Difference Between Benadryl And ZzzQuil?
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Beatrice asked

What is the difference between Benadryl and ZzzQuil? I want something for sleep. Thank you!

Aug 10, 2021
The quick answer
  • Both Benadryl and ZzzQuil contain the same active ingredient, diphenhydramine, so they work the same way in your body.
  • Benadryl is marketed for allergies while ZzzQuil is marketed as a sleep aid, but the main difference between them is how they are packaged and their inactive ingredients.
  • ZzzQuil liquid contains alcohol while Benadryl liquid does not, which is an important consideration when choosing between the two products.
A quick summary of Dr. Brian Staiger, PharmD's full answer below, condensed by AI from that answer only (not from any outside source). The pharmacist's answer is the source of record.
Medications in this answer — tap to explore

Hello and thank you for reaching out to us!

The difference between Benadryl and ZzzQuil is mostly marketing, as they contain the same active ingredient.

In fact, in many situations, you could easily substitute one for the other.

Benadryl And ZzzQuil Both Contain Diphenhydramine

Both Benadryl and ZzzQuil have the same active ingredient, diphenhydramine, and thus, work the same way.

Although Benadryl is traditionally used to help with allergy symptoms (e.g. itchy eyes, runny nose, hives, etc...), many people use it to help them fall asleep, as it is quite sedating.

ZzzQuil is essentially a way to market the sedative effects of diphenhydramine as a sleep aid.

Below are the 'Drug Facts' for both Benadryl tablets and ZzzQuil liquid. You can see that the active ingredient, diphenhydramine, is the same.

ZzzQuil Drug Facts

Benadryl Drug Facts

Although they contain the same active ingredients, Benadryl and ZzzQuil do come in different dosage forms, with different inactive ingredients.

It is important to note (as I detail below), that ZzzQuil liquid does contain alcohol, which can enhance its sedating effects (although there is now a non-alcohol version on the market too).

Benadryl And ZzzQuil Dosage Forms

Both Benadryl and ZzzQuil are available in multiple dosage forms, including:

  • Liquid
  • Tablets
  • LiquiCaps

For the solid dosage form products (e.g. tablets, LiquiCaps), Benadryl and ZzzQuil contain 25 mg of diphenhydramine per Liquicap/tablet.

The liquid form of ZzzQuil contains 50 mg of diphenhydramine per 30mL.

Benadryl is also available in additional dosage forms that ZzzQuil is not available in, including:

  • Tablets
  • Chewable tablets

Lastly, I do want to point out ZzzQuil has a product that contains melatonin, instead of diphenhydramine, and is called ZzzQuil Pure Zzzs

Benadryl And ZzzQuil Inactive Ingredients

When it comes to the liquid forms of the drugs, ZzzQuil contains alcohol (10% by volume) while the Benadryl liquid does not contain any alcohol.

In fact, Benadryl as a liquid only comes as a "children's liquid", which is still the same active ingredient (diphenhydramine), just alcohol-free.

The concentration of the ZzzQuil liquid is:

  • 50 mg diphenhydramine per 30 mL (two tablespoonfuls).

The concentration of Children's Benadryl liquid is:

  • 12.5 mg diphenhydramine per 5 mL (one teaspoonful).

The complete ZzzQuil liquid inactive ingredient list is as follows:

  • Alcohol
  • Citric acid anhydrous
  • FD&C Blue No. 1
  • FD&C Red No. 40
  • Flavor
  • High fructose corn syrup
  • Polyoxyl 40 stearate
  • Propylene glycol
  • Purified water
  • Saccharin sodium
  • Sodium benzoate
  • Sodium citrate

The complete Benadryl Children's liquid inactive ingredient list is as follows:

  • Anhydrous citric acid
  • D&C red no. 33
  • FD&C red no. 40
  • Flavors
  • Glycerin
  • Monoammonium glycyrrhizinate
  • Poloxamer 407
  • Purified water
  • Sodium Benzoate
  • Sodium chloride
  • Sodium citrate
  • Sucrose

Besides the addition of alcohol to ZzzQuil liquid, it also contains high fructose corn syrup. Children's Benadryl liquid does not contain high fructose corn syrup, but sucrose instead.

Please don't hesitate to reach out to us again with any additional questions!

References & sources
  1. Diphenhydramine Monograph — PubChem
  2. Benadryl Manufacturer Website — Benadryl.com
  3. ZzzQuil Manufacturer Website — ZzzQuil.com
Glossary — Terms in This Answer
Diphenhydramine
The active ingredient in both Benadryl and ZzzQuil that reduces allergy symptoms and causes drowsiness.
Active ingredient
The component in a medication that produces the intended therapeutic effect.
Dosage forms
Different physical formats in which a medication is available, such as tablets, liquids, or capsules.
LiquiCaps
Soft gelatin capsules containing medication in liquid or semi-solid form.
Sedating
Causing drowsiness or sleep.
Inactive ingredients
Components in a medication that do not produce the therapeutic effect but help with flavor, texture, or preservation.
Melatonin
A naturally occurring hormone that helps regulate sleep-wake cycles in the body.
Concentration
The amount of active ingredient present in a specific volume or weight of medication.
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Dr. Brian Staiger, PharmD
About the pharmacist

Dr. Brian Staiger, PharmD

Clinical Pharmacy

Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified

Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...

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