If you are already familiar with Nyquil (the cold medicine), you wouldn’t need much of introduction for Dayquil. Both Nyquil and Dayquil do the exact same except in the case of Dayquil, you wouldn’t feel the drowsiness. If you are not familiar with Nyquil, then I suggest you to read both the articles on Dayquil and Nyquil. No matter how popular the medicine is, it’s always dangerous to take any non-prescription drug without a proper knowledge. So before giving you an answer to the query, how long does Dayquil last, I take you through its usage, Do’s and Don’ts, dosage and side effects. No beating around the bush, I promise.

How Do You Want To Take Dayquil?

Dayquil is one of the most frequently used household medicines that is used for treating the generic conditions like common cold, flu or hay fever. It comes in 2 different forms. So you can go with the one of your choice.

  • Liquid
  • Liquicaps
  • Caplet
  • Nasal spray

What Does Dayquil Do?

Dayquil offers a temporary relief to the conditions like common cold, cough, stuffy nose, fever, flu, congestion, body aches and flu. It is also used to treat the other illnesses like bronchitis and sinusitis. However, Dayquil should not be used to treat the coughing conditions that aroused due to asthma and smoking.

Active ingredients found in Dayquil are Acetaminophen, Guaifenesin, Dextromethorphan, and Decongestants.

Acetaminophen – Fever reducer/pain reliever

Guaifenesin – This ingredient promotes expectoration by loosening the mucus. This process makes it easier to expel the mucus from lungs.

Dextromethorphan – It is a cough suppressant. It reduces the urge to cough by affecting a certain part of the brain.

Decongestants – This active ingredient helps in the reducing the symptoms connected with the stuffy nose.

The active ingredients found in Dayquil minimize swelling developed inside the nasal passages. It takes out the mucus out of lungs as well. Result? Quick and Easy breathing.

How Long Does Dayquil Take To Work?

You may pop a pill or swallow the liquid. Whichever the route you want to take up, Dayquil can offer an instant in not more than 40 minutes.

Dayquil liquid works faster than its capsule/caplet version. As you know, liquid reach the blood stream quicker than the capsule or caplet. If you want a more rapid relief, go snatch the bottle and take 30 ml (2 tbsp) of Dayquil Liquid. You would feel relieved in 30 minutes.

How Long Does Dayquil Last?

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According to its manufacturer Vicks, Effect of Dayquil last anywhere between 10 to 12 hours. As it purely depends on the weight and immune system of the sufferer, this duration may vary from one to the other. However, if the effect of Dayquil fades so quick, you can repeat taking the recommended dose for every 6 hours. Never cross the daily dosage limit though.

Available Formulations And Product Selection

Dayquil offers 4 different products to treat common cold and flu symptoms. It is advised to choose the product based on the particular symptoms developed on the user. Select the product that is formulated only with the ingredients used to treat your symptoms. Feeding your body with the medication that is not required can result in a newer problem. Also, never take two different OTC to treat the same symptom. Most of the Over the counter medications are formulated with the same active ingredients. This duplication often will result in the increase of overdose and so the unwanted side effects.

DayQuil Cough

how long does dayquil last

Available Form: Liquid

Active Ingredient : dextromethorphan



 DayQuil Cold & Flu


Available Forms : Liquid & Liquicaps forms

  Active Ingredients  : dextromethorphan,acetaminophen,phenylephrine  


DayQuil Severe Cold & Flu


How-Long-Does-Dayquil-LastAvailable Forms: Liquid & caplets

Active Ingredients: acetaminophen, dextromethorphan,guaifenesin, phenylephrine


DayQuil Mucus Control DM


How-Long-Does-DayQuil-Last-9Available Form: Liquid

Active Ingredients : dextromethorphan,guaifenesin



Dayquil Sinex

how llong doe dayquil last

Available Forms : Liquicaps & Nasal spray

Active Ingredients :phenylephrine, acetaminophen,oxymetazoline


Dayquil Dosage Recommendations

Take Dayquil as per the directions printed on the packaging. How long does the effect of Dayquil last is partially depend on the dosage you intake but it doesn’t mean taking more than recommended would provide a longer result. If the recommended dose is 30 ml, you can take anywhere between 0 ml to 30 ml. Exceeding this limit with the thought of attaining the faster relief will only do more harm than any good.

Usual Adult Dosage

Although Adults and children of age 12 years & above can take 30 Ml or 2 tbsp per dosage, it is important to not to exceed the daily dosage limit of 120 Ml per day.

In case of Liquid, take two soft gels with water.

Which Product To Choose?

“DayQuil Cold & Flu (LiquiCaps), DayQuil Severe Cold & Flu, DayQuil Sinex (LiquiCaps)”

Usual Pediatric Dosage

Children of age ( 6 to 12) should be treated with Dayquil only under the physician’s instructions.

Children of age 4 and below should not be treated with Dayquil. In general, they should not be treated with any OTC.

Which Product Would Your Doctor Prescribe Mostly?

“DayQuil Cough, DayQuil Mucus Control DM, DayQuil Cold & Flu (Liquid only), DayQuil Sinex (nasal spray)

Note :

You can repeat taking one dose of Dayquil for every 6 hours. Never exceed four doses per 24 hours.

Taking too much or taking it with other medications may induce the undesirable side effects. Call up the help center when you experience such issues.

Dayquil Side Effects

Most Common Side Effects

Every caplet of Dayquil contains 325 mg of Acetaminophen. Taking too much of this ingredient will cause liver damage. So it is advised to not to take any other medication that contains Acetaminophen.

Not every person who take Dayquil experience the side effects. Only a few individuals do. If you feel any of the following side effects and it lasts for more than a day, conduct your doctor immediately.

  • Nausea
  • Nervousness or anxiety
  • Excitability
  • Trouble sleeping
  • Dizziness
  • Severe Headache

Severe Side Effects That Needs Immediate Medical Attention

  • Sore throat that lasts more than two days
  • Difficulty breathing
  • Severe allergic reactions such as sudden development of rash, hives, seizures, changes in skin color
  • Hallucinations
  • Chest congestion
  • Difficulty Urinating
  • Tremor
  • Headache

Check With Your Doctor Before Taking Dayquil If You Have

  • high blood pressure
  • diabetes
  • persistent or chronic cough
  • Asthma
  • heart disease
  • liver disease
  • thyroid disease
  • Pregnant or breast feeding

Other Important Drug Facts

  • Store Dayquil in a room temperature
  • If you suspect the overdose warning, make an immediate call to 1-800-251-3374.
  • Most of the OTC medications are not reviewed by FDA. It includes Dayquil as well. However, if you suspect any serious side effects because of Dayquil, you can report it to FDA.
  • Dayquil contains 4% of sodium so avoid taking Dayquil if you are on some sodium restricted Diet.

The duration specified for how long does Dayquil last is only a rough estimation from its manufacturer and the people who used it. It may work little different on you.

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