There is no single best OTC allergy medicine for everyone, but the most effective option depends on your primary symptoms. For sneezing, itching, and a runny nose, a second-generation antihistamine like cetirizine or levocetirizine provides the strongest relief. For stuffiness and congestion, an OTC nasal steroid spray outperforms antihistamines. Many people with moderate to severe allergies get the best results using both together.
Oral Antihistamines: How They Compare
Second-generation antihistamines are the backbone of OTC allergy treatment. They block histamine, the chemical your immune system releases during an allergic reaction that causes itching, sneezing, and a runny nose. Four are widely available without a prescription: cetirizine (Zyrtec), levocetirizine (Xyzal), loratadine (Claritin), and fexofenadine (Allegra). All four work, but they are not equally potent.
In a controlled crossover study that tested all these drugs head-to-head, levocetirizine came out on top. Every single participant achieved greater than 95% suppression of the histamine response at some point during the 24-hour test period. Fexofenadine ranked next, followed by loratadine, which was the least potent of the group. Levocetirizine and fexofenadine also kicked in faster, showing measurable effects within one hour and peaking around four hours. Loratadine took about four hours just to separate from placebo.
That ranking doesn’t tell the whole story, though, because side effects matter just as much as potency. Cetirizine and its close relative levocetirizine are more likely to make you drowsy. In user-reported data, about 21% of people taking cetirizine noticed drowsiness, compared to roughly 8% for loratadine. Fexofenadine is considered the least sedating of the group. So if you need to stay sharp during the day, fexofenadine or loratadine may be the better pick despite being slightly less powerful.
A practical way to think about it: if your allergies are moderate to severe and drowsiness doesn’t bother you (or you take it at bedtime), cetirizine or levocetirizine gives you the strongest antihistamine punch. If you’re sensitive to drowsiness or need to drive and focus, fexofenadine is the best balance of effectiveness and alertness. Loratadine is the mildest option all around.
Nasal Steroid Sprays: Best for Congestion
If your main complaint is a stuffy, swollen nose, oral antihistamines alone often aren’t enough. Nasal corticosteroid sprays work differently. Instead of just blocking histamine, they reduce the broader inflammatory response that causes congestion, swelling, and post-nasal drip. They target a delayed wave of immune activity that antihistamines don’t touch, which is why doctors and allergists frequently recommend them as a first-line treatment for moderate to severe seasonal allergies.
Three nasal steroids are available OTC: fluticasone (Flonase), triamcinolone (Nasacort), and budesonide (Rhinocort). In head-to-head trials, there were no significant differences between them. Across studies, 78% to 88% of adults with seasonal allergies showed meaningful improvement with any of these sprays. Side effect rates were also comparable, with occasional nasal dryness, mild nosebleeds, or brief headaches being the most common complaints.
The catch is patience. Nasal steroids need consistent daily use for several days before they reach full effectiveness. They’re not the kind of medicine you grab when symptoms suddenly hit. Starting them a week or two before your allergy season begins gives you the best results. If you only get occasional symptoms a few days per year, an antihistamine alone is simpler and works faster.
Combining an Antihistamine and a Nasal Spray
Because antihistamines and nasal steroids work through completely different mechanisms, using both is safe and often more effective than either one alone. The antihistamine handles the immediate histamine response: the itching, sneezing, and watery eyes. The nasal spray tamps down the deeper inflammatory process responsible for congestion and sinus pressure. For people with allergies that hit hard across multiple symptoms, this combination covers both phases of the allergic reaction.
What About Decongestants?
Many OTC allergy products include a decongestant for stuffiness. There are two to know about, and one of them doesn’t work. Oral phenylephrine, found in many products labeled with a “D” or “congestion” on the box, was ruled ineffective as a nasal decongestant by an FDA advisory panel. It simply doesn’t relieve stuffiness when swallowed as a pill.
Pseudoephedrine, on the other hand, does work well for short-term congestion relief. It’s kept behind the pharmacy counter (you’ll need to show ID to buy it) because of its use in manufacturing methamphetamine, but no prescription is required. Phenylephrine nasal spray, as opposed to the oral form, is also effective. However, nasal decongestant sprays should only be used for a few days at a time to avoid rebound congestion, where your nose becomes more stuffed up than before once you stop.
Eye Drops for Itchy, Watery Eyes
If allergies hit your eyes the hardest, oral antihistamines help somewhat, but targeted eye drops work faster on ocular symptoms. Ketotifen (sold as Zaditor or Alaway) is the most widely available OTC allergy eye drop. It both blocks histamine and stabilizes the mast cells that release it, providing relief for itching, redness, and watering that can last up to 12 hours per dose.
Olopatadine (Pataday) is another option now available OTC. Studies show comparable effectiveness between ketotifen and olopatadine for seasonal eye allergy symptoms, so either is a solid choice. Ketotifen tends to be less expensive.
Choosing Based on Your Symptoms
- Mainly sneezing and itching: An oral antihistamine alone is usually enough. Cetirizine or levocetirizine for maximum strength, fexofenadine if you want to avoid drowsiness.
- Mainly congestion: A nasal steroid spray (fluticasone, triamcinolone, or budesonide) is more effective than any antihistamine for stuffiness.
- Sneezing, itching, and congestion together: Pair an oral antihistamine with a daily nasal steroid spray.
- Mainly itchy or watery eyes: Add ketotifen or olopatadine eye drops. These work alongside oral antihistamines without interaction concerns.
- Occasional flare-ups only: A fast-acting antihistamine like cetirizine taken as needed is the simplest approach.
Safety for Children and During Pregnancy
The FDA advises against giving any OTC antihistamine or cold medicine to children under 2. For children 2 and older, liquid formulations of cetirizine, loratadine, and fexofenadine are available with age-appropriate dosing on the label. Measure doses with the cup or syringe included in the package, not a kitchen spoon. Be especially careful with multi-symptom products, which can duplicate ingredients and lead to accidental overdosing if combined with a standalone allergy medicine.
During pregnancy, loratadine and cetirizine are the oral antihistamines most commonly recommended by health care providers. For pregnant individuals with more significant symptoms, nasal steroid sprays like budesonide, fluticasone, and mometasone are options that can be used alongside an antihistamine at the lowest effective dose.