Does Dayquil Make You Drowsy?

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Dayquil is an over-the-counter medicine that can be in the form of cough medicine or two-in-one or three-in-one variety formulated to temporarily manage flu, common colds, bronchitis, and sinusitis symptoms such as cough, body aches, and stuffy nose. Medicines with such intended use are known to have a drowsiness or sleepiness effect. Thus, most people wonder and ask, “Does Dayquil make you drowsy?” or “Does Dayquil Severe make you drowsy?” so that they can take the necessary precautions once they’ve taken it.

So, does Dayquil make you drowsy? Though marketed as non-drowsy, at high dosages, some will still experience drowsiness. Besides, non-drowsy means not all, but a majority of the population will not experience drowsiness. For Dayquil Severe, drowsiness is more common due to the guaifenesin content.

Apart from drowsiness or sleepiness, it is also best to learn whether or not Dayquil will keep you awake since generally; you won’t take just one dose of the medicine in a day. That way, you can have a better plan on when to take the first dose. Additionally, we will talk about the different forms of Dayquil to know which one best suits your needs, as well as the right dosage for each variety.

Sleepy Woman Yawning

Does Dayquil Keep You Awake?

Apart from knowing the answers to “Does Dayquil Severe make you drowsy?” and “Does Dayquil make you sleepy or drowsy?”, it is also important to understand if the medicine will keep you awake at night. Remember, sleeping is one of the best ways for our bodies to recharge, for us to recover quickly from illness, and to help boost our immune systems.

Some people’s concern about whether Dayquil keeps a person awake or not roots from its non-drowsy label or formulation. They are worried that it might have strong stimulants to make it a more effective non-drowsy medication. That said, as similar to its drowsy effects, some people might experience one of its known severe side effects, which is difficulty in sleeping.

The short-term insomnia effect might be due to taking too much of the medicine since it has minimal amounts of stimulants, and similar to consuming energy drinks, when the stimulant effect wears off, you’ll feel tired, dizzy, or drowsy, even if you were able to shut-off your eyes for a few hours.

Components of Concern

Let’s break down the specific active components that can cause short-term and/or drowsiness effects in some people to have a better understanding and, in turn, prevent it from happening.

  • Dextromethorphan (DXM)
    DXM or dextromethorphan is the component of Dayquil responsible for relieving cough symptoms. At a dosage ranging from 100 to 200 milligrams, DXM acts as a mild form of stimulant, which can keep you awake, especially if you’ll consume other stimulants such as coffee. On the other hand, from above 200 to 400 milligrams, most users might experience euphoric feelings and hallucinations.
  • Phenylephrine
    The most common phenylephrine function is decongesting a stuffy nose decongestion. It will help you breathe more comfortably.
    It is a type of stimulant that acts on particular central nervous system receptors that will lead to difficulty in sleeping or short-term insomnia when taken at high doses. It may also cause anxiety, restlessness, headache, dizziness, and nervousness, especially at super-high doses.
    The acceptable oral dosage of phenylephrine as a nasal decongestant is 10mg when taken every four hours, at a maximum of 60mg in 24 hours.

Dayquil Formulation

With those pieces of information in mind, here is the mentioned components’ exact dosage in each Dayquil variety:

  • Dayquil Severe Cold & Flu Liquid: 20mg DXT HBr, 10mg Phenylephrine HCl
  • Dayquil Severe Cold & Flu Caplet and Liquicap: 10mg DXT HBr, 5mg Phenylephrine HCl
  • Dayquil Cold & Flu Liquicap and Liquid: 10mg DXT HBr, 5mg Phenylephrine HCl
  • Dayquil Cough & Congestion Liquid: 15mg DXT HBr
  • Dayquil Cough Liquid: 10mg DXT HBr

From the numbers given above, you can quickly see that Dayquil has been formulated in a way that it will not cause both drowsiness and insomnia effects in most users, especially when taken as prescribed.

Do note, though, that people who have a specific reaction to one or more of the components might also experience any or both side effects, even when taken at the minimal or required dose. At this point, you might need a differently formulated medicine, so seek the help of a physician.

For your complete information and to know the medicine’s specific purpose, do note that another active component of Dayquil and Dayquil Severe is acetaminophen, which is a pain reliever and fever-reducing. Also, Dayquil Severe has guaifenesin, a mucus expectorant, or a compound that can help expel mucus.

Dayquil Dosage

Since dosage has a significant role in answering the question, “Does Dayquil make you sleep and keep you awake even when you’re under your high-quality down comforter (view on Amazon)?” with a yes, let us have a rundown of the required dosage for each Dayquil variety. Each dose mentioned here is for children 12 years old and above, as well as for adults.

First off, for Dayquil Cough Liquid, Dayquil Cold & Flu Liquid, and Dayquil Cold & Flu Severe Liquid, you should take 30ml every four hours, but make sure you don’t exceed four doses within 24 hours. The same amount applies to Dayquil Cough & Congestion Liquid, but the maximum allowable number of doses for 24 hours is six.

Next, for the Dayquil Cold & Flu Liquicapyou must take two liquicaps every four hours with a limit of four doses in 24 hours. Lastly, for the Dayquil Cold & Flu Severe Liquicap and Caplet varieties, you can take two caps every four hours, and the maximum allowable dose for 24 hours is six.

For the liquid types, make sure you use the cap provided to prevent under- or over-dosing. Likewise, if you plan to give this medicine to children under 12 years old, always consult a physician for proper dosing. That said, children under four years old can’t take Dayquil.

Which Is Better, DayQuil Pills or Liquid?

Woman Pouring Liquid Syrup Medicine into a Cup

From the list of Dayquil varieties above, you might have noticed that the combination form comes in both liquid and liquicaps or caplets. Hence, besides wondering and asking the question, “Can Dayquil make you sleepy or toss and turn in your eco-friendly, CertiPUR-US-certified memory foam mattress (view on Amazon)?“, most of you would want to know which one would be better to buy and take.

When it comes to medicine, not just Dayquil, those in the liquid form are better than the pill, tablet, capsule, or caplet forms due to the following reasons:

Easy Consumption

Obviously, any liquid is easier to swallow than one solid caplet or pill, and since it’s already fluid, it really doesn’t require breakdown and digestion.


Since the body doesn’t need to break down Dayquil liquid, it absorbs its active ingredients within one to four minutes. On the other hand, the caplet and liquicap forms need to undergo digestion, which usually takes 20 to 30 minutes, before the body can assimilate its active ingredients. Not only will this slow down its initial medicinal effects, but it will also decrease the amount of metabolized active ingredients absorbed.


Based on the assimilation rate of the two varieties, we can conclude that the liquid form is more potent than the pill, caplet, liquicap, or capsule form. In fact, experts claim that the effect of one teaspoon of liquid medicine is equivalent to the effects of 20 pills. They also say that the human body will use 98% of the liquid extract, while it will only utilize 39% to 53% of the pill.

On that note, since Dayquil and Dayquil Severe are available in liquicap form, you must note that as compared with the caplet form, this is easier to consume. Similarly, the body will digest and absorb it faster than the caplet, so it also has better potency.

Additionally, if you go back to the formulation of each variety of Dayquil, the liquid form contains a higher amount of the active ingredients, so again, they’re more potent and will have a better effect on the targeted symptoms.

Does Dayquil Make You Drowsy: Final Thoughts

Having colds, flu, cough, and sinusitis can be daunting, especially if you need to accomplish a lot of work or run multiple errands within the day. The good thing is that there are already many OTC medicines that can help relieve your symptoms, and one of the most popular is Dayquil.

That said, if the medicine makes you sleepy or drowsy, you wouldn’t be productive at all. Likewise, if it will prevent you from dozing off on your breathable pillow (view on Amazon), you won’t recover as quickly as expected. Hence, keeping in mind the answer to the question, “Can Dayquil make you sleepy or keep you up at night?” is essential.

To sum up, you won’t experience side effects, particularly drowsiness or sleepiness, insomnia, and other effects that can keep you awake, if you do not exceed the allowable dose of any of the Dayquil varieties. If you still experience any side effects even if you strictly followed the dosage requirement, visiting a physician is the best action to take.

Remember, every person’s body is different, so the effect on one person would be different from the other.

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