Nyquil Vs. ZzzQuil: What Is The Difference?
In our latest question and answer, we discuss the difference between NyQuil and ZzzQuil.
Which is better for sleeping - ZzzQuil or plain Nyquil?
Jul 27, 2022- ZzzQuil contains diphenhydramine and is designed only as a sleep aid, while NyQuil contains doxylamine plus additional ingredients to treat cold and flu symptoms like cough, fever, and pain. Both products' antihistamines work similarly, taking about 30 minutes to work and lasting 4 to 6 hours, though individuals may respond better to one than the other. If you only need help falling asleep, ZzzQuil is a better choice to avoid unnecessary ingredients.
Hello and thank you for your question! There are a few differences between NyQuil and ZzzQuil that we are happy to discuss here.
They Contain Different Antihistamines
First and foremost, Nyquil and ZzzQuil contain sedating antihistamines, but different ones. ZzzQuil contains diphenhydramine, the active ingredient in Benadryl, while Nyquil contains doxylamine.
Both antihistamines cause sedation shortly after administration and help you to fall asleep.
Although NyQuil and ZzzQuil contain different sedating antihistamines (diphenhydramine vs. doxylamine), those antihistamines are very similar in terms of how quickly they work (around 30 minutes), how long they last (4 to 6 hours), and how potent they are.
Direct comparative studies and evaluations are limited, so it is difficult to say one is better than the other, but overall, they are quite comparable. Individuals will vary in regard to which ingredient works best for them.
NyQuil Contains More Ingredients
In addition to the difference in antihistamines, Nyquil contains additional ingredients for the treatment of cough/cold symptoms.
ZzzQuil contains diphenhydramine as the only ingredient. It is intended solely for use as a nighttime sleep aid.
NyQuil on the other hand contains additional ingredients:
- Acetaminophen (the active ingredient in Tylenol) for treating fever/pain.
- Dextromethorphan for suppressing cough.
- Doxylamine as mentioned above, for sedation. Sedating antihistamines may also help relieve a runny nose as well as cough due to post-nasal drip.
Final Words
If you are only in need of something to assist in falling asleep, it's better to just stick with ZzzQuil. It will most likely do the job, without the extra ingredients and side effects you may experience from the additional ingredients contained in Nyquil.
Thanks again for your question and please feel free to reach out with any further questions in the future.
References & sources
Glossary — Terms in This Answer
- Antihistamines
- Medications that block histamine in the body to reduce allergic reactions, itching, and other symptoms.
- Diphenhydramine
- A sedating antihistamine that causes drowsiness and is commonly used as a sleep aid.
- Doxylamine
- A sedating antihistamine used to help with sleep and cold symptoms.
- Sedation
- A state of reduced consciousness or drowsiness caused by medication.
- Acetaminophen
- A pain reliever and fever reducer commonly found in over-the-counter medications.
- Dextromethorphan
- A medication ingredient that suppresses cough by affecting the brain's cough reflex.
- Post-nasal drip
- The drainage of mucus from the nasal passages down the back of the throat.
Dr. Brian Staiger, PharmD
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...
More answers from Brian →