Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to over-the-counter (OTC) medication.

DayQuil is a popular OTC cold and flu treatment sold by a company called Vicks, and similar to our review of NyQuil ingredients, our goal is to publish a review of the ingredients in DayQuil from a health and efficacy perspective. Vicks claims that this product provides relief from nine different cold symptoms like sore throat and runny nose.

But what are the active ingredients in DayQuil and are they safe and effective based on medical research? Does the product contain any questionable additive ingredients? Are DayQuil LiquiCaps a better option than the liquid version of DayQuil? And is there a natural alternative?

In this article we'll answer all of these questions and more as we review the ingredients in both DayQuil Liquid and DayQuil LiquiCaps based on medical studies to give our take on whether the cold medicine is likely to be effective and if it's healthy or not.

We'll highlight some questionable additive ingredients in DayQuil products, and share a natural alternative.

DayQuil Liquid Active Ingredient Analysis

DayQuil Liquid contains three active ingredients.

Acetaminophen is a pain reliever, and a medical trial on patients with post-operative surgical pain found it to reduce pain in 35% of trial participants.

Dextromethorphan hydrobromide is approved by the FDA as a cough suppressant. Drug ingredients require significant clinical backing before FDA approval, so we consider this ingredient to be effective.

The manufacturer of DayQuil was sued in 2022 over this ingredient. The product is marketed as "non-drowsy," and the plaintiff alleges that dextromethorphan hydrobromide causes drowsiness, and cites a study which found that over 10% of people using this ingredient experienced drowsiness.

Phenylephrine hydrochloride is described by the manufacturer as a nasal decongestant, but it may not be the most effective choice. A clinical trial published in the Annals of Allergy, Asthma & Immunology journal tested this ingredient and found that it did not cause a significant improvement in nasal decongestion scores.

A more recent clinical trial reported similar results: even when dosed up to 40 milligrams (mg) every four hours, which is 4x the dose in DayQuil, phenylephrine hydrochloride was no better than placebo relieving nasal congestion in patients with allergies.

We believe that this formulation is likely to be effective overall, and especially for pain relief and cough suppression. We find the medical backing for the nasal decongestant ingredient to be lacking.

A one minute animated video from Vicks explains how these ingredients work:

Questionable Additive Ingredients in DayQuil Liquid 

DayQuil Liquid contains a number of questionable inactive ingredients.

Sodium saccharin is an artificial sweetener that was found to be associated with increased risk of diabetes, obesity and impaired kidney function in at least one animal study. 

Sucralose is another artificial sweetener which has been clinically shown to have negative effects on blood sugar and insulin, as we documented in our review of 5 Hour Energy ingredients.

FD&C Yellow No. 6 is an artificial food dye which was found in a medical review to contain carcinogens. 

Citric acid is a preservative and flavor enhancer which often produced using a fungus called Aspergillus niger, according to a medical review published in the Toxicology Reports journal. It was found to cause whole-body inflammation in some individuals.

Do LiquiCaps Have Better Ingredients?

The active ingredients in DayQuil LiquiCaps are the exact same as those in DayQuil Liquid. The inactive ingredients, shown above, are slightly different.

This product contains two artificial colorants rather than one. It contains the same FD&C Yellow No. 6 as the liquid formulation, but also contains FD&C Red No. 40. A medical review documented that Red No. 40 contains a compound called benzidine which is carcinogenic to humans and animals.

Titanium dioxide is included in this formulation, and is banned for use as a food additive in the European Union (E.U.) due to toxicity concerns.

We consider the LiquiCaps to be healthier than the Liquid because they are free of artificial sweeteners and citric acid.

Our Clean Immune Support Picks

Bulletproof Immune Complex is our top value immunity supplement, costing under $20 at the time of updating this article.

This supplement contains the same vitamin C dose (1,000 mg) as in Emergen-C, which we already established to be effective. It also contains 450 mg of elderberry fruit extract, which was shown in a clinical trial to decrease symptom load and reduce cold duration by a full two days.

Performance Lab Immune is our top premium immunity supplement, because of its potent formulation.

This supplement contains the patented postbiotic IMMUSE, which is backed by 15 clinical trials and is clinically shown to activate a specific type of immune cell that helps fight infection and support overall wellness. 

Pique Daily Radiance is our top food-based immune supplement, because it's a gel that provides 1,000 milligrams (mg) of vitamin C per serving, and also contains organic elderberry juice concentrate (which is clinically shown to support the immune system).

Conclusion

DayQuil is effective for reducing symptoms of infection like cough and runny nose because it contains three active ingredients which are clinically shown to reduce pain and suppress cough.

There are a number of inactive ingredients in DayQuil products like artificial sweeteners and artificial food dye which we consider to be strange choices for a product category meant to improve the health of users.

For consumers who are more naturally inclined, there are products on the market formulated for reducing symptoms of the cold which are made with entirely natural, plant-based ingredients and free of questionable additives.