Zyrtec and Xyzal are closely related antihistamines used to relieve allergy symptoms, but they are not exactly the same medicine. Zyrtec contains cetirizine, while Xyzal contains levocetirizine, a closely related form of cetirizine. Both work by blocking histamine, which contributes to symptoms such as sneezing, runny nose, itching, and watery eyes.
The biggest practical differences are their active ingredients, labeled doses, dosing instructions, and certain precautions. Neither should automatically be considered “better” for everyone, and both can cause drowsiness.
Quick Answer
Zyrtec contains cetirizine, while Xyzal contains levocetirizine. Levocetirizine is the active enantiomer of cetirizine, which is why the two medicines are pharmacologically very closely related.
In common U.S. OTC tablets, Zyrtec contains 10 mg of cetirizine, while Xyzal contains 5 mg of levocetirizine. The smaller number on Xyzal’s label does not mean that Xyzal is simply half as strong.
Both can relieve allergy symptoms and both can cause drowsiness.
Zyrtec vs Xyzal at a Glance
| Feature | Zyrtec | Xyzal |
| Active ingredient | Cetirizine HCl | Levocetirizine dihydrochloride |
| Drug class | Antihistamine | Antihistamine |
| Common OTC tablet strength | 10 mg | 5 mg |
| Main allergy symptoms treated | Runny nose, sneezing, itchy/watery eyes, itchy nose/throat | Runny nose, sneezing, itchy/watery eyes, itchy nose/throat |
| Drowsiness | May occur | May occur |
| OTC dosing for adults 12–64 | 1 tablet daily according to label | 1 tablet daily in the evening |
| Kidney precaution | Ask a doctor if you have kidney disease | OTC label says do not use if you have kidney disease |
| Alcohol warning | Avoid alcoholic drinks | Avoid alcoholic drinks |
The table reflects the current U.S. OTC labels and should not be interpreted as individualized medical advice.
What Is Zyrtec?
Zyrtec is a brand name for cetirizine, an antihistamine used to temporarily relieve common allergy symptoms.
The current OTC Zyrtec tablet label lists cetirizine HCl 10 mg as its active ingredient. It is indicated for symptoms such as runny nose, sneezing, itchy or watery eyes, and itching of the nose or throat.
Cetirizine works by blocking the effects of histamine, a substance involved in allergic reactions.
Zyrtec is available in different formulations, including tablets and other products, so the exact product label matters when determining dosage and age restrictions.
What Is Xyzal?
Xyzal is a brand name for levocetirizine, another antihistamine used to relieve allergy symptoms.
The current U.S. OTC Xyzal Allergy 24HR tablet contains 5 mg of levocetirizine dihydrochloride. Its label lists temporary relief of runny nose, sneezing, itchy or watery eyes, and itching of the nose or throat caused by hay fever or other respiratory allergies.
For adults and children ages 12–64, the current OTC label directs users to take one 5 mg tablet once daily in the evening and not more than one tablet in 24 hours.
What Is the Difference Between Zyrtec and Xyzal?
The most important difference is their active ingredient:
- Zyrtec → cetirizine
- Xyzal → levocetirizine
The relationship is unusually close. Cetirizine is a racemic mixture containing two mirror-image forms, while levocetirizine is one of those enantiomers—the pharmacologically active form.
That explains why the medicines can appear very similar in their effects.
However, it would be misleading to conclude that they are simply the same product under different brand names. Their OTC labels have different dosing instructions and precautions.
The dose numbers are different
A typical OTC Zyrtec tablet contains 10 mg cetirizine, whereas a typical OTC Xyzal tablet contains 5 mg levocetirizine.
That does not mean you can compare the numbers directly and say that one is twice as strong.
The drugs are different chemical forms, so milligram amounts should not be interpreted like two versions of the same ingredient.
Are Zyrtec and Xyzal Basically the Same?
They are very closely related, but they are not identical.
A useful way to remember the relationship is:
Zyrtec contains the parent drug mixture; Xyzal contains the active levocetirizine form.
Scientific literature describes cetirizine as a racemic mixture of levocetirizine and dextrocetirizine, while levocetirizine is the active enantiomer.
This close relationship helps explain why both medications are used for similar allergy symptoms.
Zyrtec vs Xyzal: Which Works Better?
There is no universal answer that one is better for every person.
Both are effective antihistamines, and the choice can depend on factors such as:
- symptom response
- side effects
- dosing preferences
- age
- other medicines
- kidney function
- individual medical history
The official Xyzal website reports similar relief compared with Zyrtec in its cited comparison studies, while other clinical evidence has compared the two directly.
Therefore, avoid making a blanket claim such as “Xyzal is always stronger” or “Zyrtec always works better.”
Individual response matters.
Zyrtec vs Xyzal: Drowsiness and Side Effects
One of the most common misconceptions is that these medications are completely non-drowsy.
They are generally considered newer, less-sedating antihistamines than older drugs such as diphenhydramine, but drowsiness can still occur with both.
The current Zyrtec OTC label warns that drowsiness may occur.
The current Xyzal OTC label also warns that drowsiness may occur and advises caution with driving or operating machinery. It also warns that alcohol, sedatives, and tranquilizers can increase drowsiness.
Importantly, a randomized, double-blind crossover study comparing 5 mg levocetirizine with 10 mg cetirizine found no statistically significant difference in sedation between the two treatments in the studied participants.
So it is inaccurate to promise that Xyzal will necessarily make someone less sleepy than Zyrtec.
Zyrtec vs Xyzal: Dosage
For common U.S. OTC adult products:
Zyrtec: The current label lists 10 mg cetirizine per tablet.
Xyzal: The current label lists 5 mg levocetirizine per tablet, with once-daily evening dosing for adults and children 12–64.
These are label-specific instructions, not a recommendation to switch between medications or adjust your dose.
Different formulations, ages, medical conditions, and prescription products can have different instructions.
Kidney and Other Precautions
This is one area where the current OTC labels have a particularly important difference.
The Xyzal OTC label says:
- do not use if you have kidney disease
- ask a doctor if you have trouble urinating or emptying your bladder
- use caution because drowsiness may occur
The current Zyrtec OTC label says to ask a doctor before use if you have liver or kidney disease, because a different dose may be needed.
This is a good example of why readers should not assume that two closely related medicines have identical labels.
If you have kidney disease, liver disease, urinary problems, take sedatives, or are considering long-term use, a pharmacist or healthcare professional can help determine which product and dose are appropriate.
An Important Long-Term Use Warning
There is also a newer safety issue that should be included in current Zyrtec-versus-Xyzal information.
In May 2025, the FDA warned about rare but severe itching after stopping long-term use of cetirizine or levocetirizine. Reported cases generally involved people who had taken these medicines daily for months or years, although some cases occurred after shorter use.
The FDA recommends contacting a healthcare professional if severe itching develops after stopping either medicine, particularly following long-term daily use.
This does not mean that most people will experience this reaction. The FDA describes it as rare, but it is important current safety information for people considering prolonged daily use.
Can You Take Zyrtec and Xyzal Together?
Do not assume that taking both together is appropriate.
Because Zyrtec and Xyzal are closely related antihistamines, taking them together could unnecessarily duplicate antihistamine therapy and potentially increase side effects such as drowsiness.
If one medication is not adequately controlling your symptoms, speak with a doctor or pharmacist rather than combining the two on your own.
Common Mistakes With Zyrtec and Xyzal
Mistake 1: “Xyzal is just a stronger Zyrtec.”
Why it is misleading:
Xyzal contains levocetirizine, while Zyrtec contains cetirizine. They are closely related, but “stronger” is an oversimplification.
Mistake 2: “Xyzal cannot cause drowsiness.”
Correct:
Both products warn that drowsiness may occur.
Mistake 3: “5 mg must be half as strong as 10 mg.”
Why it is wrong:
The two numbers refer to different active ingredients. Milligram amounts cannot be compared directly as though the medicines were identical.
Mistake 4: “The two labels have exactly the same precautions.”
Correct:
Their current OTC labels differ in important ways, including kidney-related instructions and dosing directions.
How to Remember the Difference
Use this simple rule:
Zyrtec = cetirizine.
Xyzal = levocetirizine.
Then remember that levocetirizine is the active enantiomer of cetirizine.
That explains why the two medicines are closely related without treating them as identical drugs.
Which One Should I Use?
A practical decision guide:
If you are comparing the ingredients →
Zyrtec contains cetirizine; Xyzal contains levocetirizine.
If you are comparing common OTC tablet strengths →
Zyrtec commonly contains 10 mg cetirizine; Xyzal commonly contains 5 mg levocetirizine.
If you are worried about drowsiness →
Both can cause it. Neither should automatically be considered non-drowsy.
If you have kidney disease →
Do not choose between them based on a general internet comparison. Their current OTC labels have different kidney-related instructions, so ask a healthcare professional.
If you have been taking either medicine long term →
Be aware of the FDA warning concerning rare severe itching after discontinuation.
If you are wondering whether to take both →
Ask a doctor or pharmacist rather than combining them yourself.
Zyrtec or Xyzal? Practice Examples
1. You want to know the active ingredient in Zyrtec.
Answer: Cetirizine.
2. You want to know the active ingredient in Xyzal.
Answer: Levocetirizine.
3. You think Xyzal cannot cause sleepiness.
Answer: Incorrect.
Its current OTC label warns that drowsiness may occur.
4. You see 10 mg Zyrtec and 5 mg Xyzal and assume Zyrtec is twice as strong.
Answer: Incorrect.
The medications contain different active ingredients, so the milligram numbers cannot be compared that way.
5. You have kidney disease and want to choose between them without professional advice.
Answer: Don’t make the choice from the milligram numbers alone.
The current OTC labels contain different kidney-related warnings.
6. You have taken one of these medicines every day for years and develop severe itching after stopping.
Answer: Contact a healthcare professional.
The FDA has specifically warned about this rare reaction after long-term use of cetirizine or levocetirizine.
Frequently Asked Questions
What is the main difference between Zyrtec and Xyzal?
Zyrtec contains cetirizine, while Xyzal contains levocetirizine. Levocetirizine is the active enantiomer of cetirizine, making the two medicines closely related.
Is Xyzal stronger than Zyrtec?
It is too simplistic to say that Xyzal is universally stronger. The medicines contain different but closely related active ingredients, and individual response varies.
Does Xyzal make you less sleepy than Zyrtec?
Not necessarily. Both can cause drowsiness, and a controlled trial found no significant difference in sedation between levocetirizine and cetirizine in the studied participants.
Can Zyrtec and Xyzal be taken together?
They should not be combined on your own. Because they are closely related antihistamines, consult a healthcare professional before using them together.
Is 5 mg of Xyzal the same as 10 mg of Zyrtec?
They are not the same drug or the same milligram dose. Xyzal contains 5 mg levocetirizine, while common Zyrtec tablets contain 10 mg cetirizine.
Which one is better for allergies?
Neither is universally better for everyone. The appropriate choice depends on the person’s symptoms, response, side effects, age, medical conditions, and other medications.
Can you stop Zyrtec or Xyzal suddenly?
The FDA has warned that rare severe itching can occur after stopping long-term daily use of cetirizine or levocetirizine. If you have been taking either medication long term, especially for months or years, discuss discontinuation with a healthcare professional.
Are Zyrtec and Xyzal the same medicine?
No. They are different medicines with closely related active ingredients: cetirizine in Zyrtec and levocetirizine in Xyzal.
Conclusion
The difference between Zyrtec and Xyzal comes down primarily to their active ingredients: Zyrtec contains cetirizine, while Xyzal contains levocetirizine. Because levocetirizine is the active enantiomer of cetirizine, the two antihistamines are closely related and treat many of the same allergy symptoms.
