Xyzal is generally more effective than Claritin at reducing allergy symptoms. A meta-analysis of clinical trials found that Xyzal (levocetirizine) produced significantly greater improvement in total symptom scores compared to Claritin (loratadine), with roughly three times the effect size when both were measured against placebo. That said, Xyzal is also more likely to cause drowsiness, so “better” depends on what matters most to you.
How They Compare on Symptom Relief
Both Xyzal and Claritin are second-generation antihistamines, meaning they’re designed to control allergies without the heavy sedation of older drugs like Benadryl. But they’re not equally potent. In a head-to-head skin test, levocetirizine (Xyzal’s active ingredient) reduced histamine-triggered swelling by 68%, skin redness by 60%, and itching by 91%. Loratadine’s effects on the same measures were inconsistent and not statistically significant.
That potency difference shows up in real-world symptom relief too. The meta-analysis comparing the two found effect sizes of -0.59 for levocetirizine versus -0.21 for loratadine, both measured against placebo. In practical terms, people taking Xyzal reported noticeably better control of sneezing, runny nose, congestion, and itchy eyes than those taking Claritin.
Speed and Duration of Relief
Xyzal starts working faster. In an environmental exposure study (where participants sit in a room filled with pollen to simulate real allergy conditions), levocetirizine provided meaningful relief within about one hour. Desloratadine, the active form that loratadine converts into after you swallow it, took closer to three hours to kick in. Both medications are dosed once daily and marketed as 24-hour drugs, but how well they hold up over that full day differs.
Levocetirizine maintained strong histamine-blocking activity, suppressing skin reactions by more than 65% even at the 24-hour mark. It hit peak effect around four hours after taking it and stayed stable for about 12 hours before tapering slightly. Desloratadine, by contrast, failed to reach the same threshold of consistent suppression over 24 hours in the same skin testing. This means Xyzal is less likely to “wear off” before your next dose.
Side Effects and Drowsiness
This is where Claritin has a genuine advantage. Loratadine is one of the least sedating antihistamines available. Most people feel no drowsiness at all, which is why it became so popular for daytime use. Xyzal, while far less sedating than first-generation antihistamines, does cause noticeable sleepiness in some people. Studies typically report drowsiness rates of around 5 to 6% with levocetirizine versus about 2% with loratadine.
For some people, this mild sedation is actually welcome, especially if allergies are disrupting sleep. But if you need to stay sharp during the day, or if you’re sensitive to medications that cause any drowsiness at all, Claritin is the safer pick. Taking Xyzal at bedtime can help sidestep this issue for many users.
Use in Children
Both medications are available in liquid and chewable forms for kids. Claritin is approved for children as young as two years old, with a standard dose of one teaspoon (5 mg) of the liquid for ages two through five, and double that for children six and older. Xyzal is also approved starting at age two in its oral solution form, with lower doses for younger children. Neither should be given to children under two without a pediatrician’s guidance.
Who Should Be Cautious With Xyzal
Xyzal is processed primarily through the kidneys, which means people with reduced kidney function need dose adjustments. For mild kidney impairment, the standard 5 mg dose is cut in half. For moderate impairment, that reduced dose is taken only every other day. People with severe kidney disease may only take it twice a week, and those on dialysis or with end-stage kidney disease should avoid it entirely. Claritin is processed mainly through the liver, making it a more straightforward choice for people with kidney problems.
Which One to Choose
If your allergies are mild and you want the lowest possible chance of drowsiness, Claritin works well and has a long track record of being easy to tolerate. It’s a solid everyday option for people whose symptoms are manageable but annoying.
If Claritin isn’t cutting it, or if your allergies are moderate to severe, Xyzal is the stronger option by a meaningful margin. The clinical evidence consistently shows better symptom control, faster onset, and more reliable 24-hour coverage. Many allergists recommend trying it when loratadine falls short, and taking it before bed minimizes any drowsiness. Both are available over the counter and comparably priced as generics, so switching is easy if one isn’t working for you.