Cetirizine and levocetirizine both treat allergies, but levocetirizine causes less drowsiness. Learn why, how they compare in effectiveness, side effects, and cost-and which one is right for your daily life.
Zyrtec vs Xyzal: Which Antihistamine Works Better for Allergies?
When it comes to Zyrtec, a brand-name antihistamine containing cetirizine, used to treat seasonal allergies and chronic hives. Also known as cetirizine, it's one of the most common over-the-counter allergy pills in the U.S. and UK, you’re not just picking a pill—you’re choosing how your day feels. Xyzal, the brand version of levocetirizine, which is the active isomer of cetirizine and designed for more targeted histamine blocking. It’s often marketed as a stronger, cleaner version of Zyrtec. Both treat runny nose, sneezing, and itchy eyes, but they’re not interchangeable. Zyrtec is available generically and costs less. Xyzal is usually prescription-only in many places and carries a higher price tag. So which one actually gives you better relief without the drowsiness?
Here’s the simple truth: Zyrtec works fast—most people feel relief within an hour. But about 1 in 6 users report feeling sleepy, especially at higher doses. That’s because cetirizine crosses the blood-brain barrier a little more easily. Xyzal, the purified form of cetirizine, removes the less effective half of the molecule, leaving only the part that blocks histamine without as much brain impact. Also known as levocetirizine, it’s engineered to be more selective. Studies show Xyzal causes less drowsiness than Zyrtec, and some users say it lasts longer. But the difference isn’t huge—most people won’t notice a major change unless they’re super sensitive to side effects. If you drive for a living or work with heavy machinery, Xyzal might be the safer pick. If you’re on a budget and just need relief, Zyrtec’s generic version does the job just fine.
Neither is a cure. Both treat symptoms, not the root cause of allergies. And neither works well for nasal congestion alone—you might still need a decongestant or nasal spray. But if your main problem is sneezing, itching, or watery eyes, you’ve got two solid options. The real difference comes down to your body’s response. Some people swear by Xyzal. Others get the same relief from a $5 bottle of generic Zyrtec. Try one. If it makes you tired or doesn’t last, switch. No doctor’s note needed. You’re not choosing between good and better—you’re choosing what fits your life, your schedule, and your wallet.
Below, you’ll find real comparisons, user experiences, and cost breakdowns from people who’ve tried both. No fluff. Just what works, what doesn’t, and what you should know before you buy.