Nasal sprays contain an active ingredient designed to treat a specific problem, mixed with several inactive ingredients that keep the formula stable, comfortable, and safe to spray into your nose. What’s inside depends entirely on the type of spray: decongestants, steroid sprays, antihistamine sprays, and plain saline sprays all have different formulations. Here’s what goes into each one.
Decongestant Sprays
Over-the-counter decongestant sprays rely on ingredients called sympathomimetics, which work by tightening the tiny blood vessels inside your nasal passages. When those vessels shrink, the swollen tissue deflates and air flows through more easily. The two most common active ingredients are oxymetazoline (found in Afrin and similar brands) and xylometazoline, both typically dosed at 0.5 mg per milliliter of solution. Oxymetazoline provides up to 12 hours of relief from a single dose.
These sprays carry an important limitation. After about three consecutive days of use, they can trigger a condition called rebound congestion, where the nasal lining swells up worse than before. The packaging typically warns you not to exceed three days, and that guideline exists because the spray itself starts causing the very problem it’s supposed to fix.
Steroid Sprays
Steroid nasal sprays are the go-to treatment for allergies and chronic nasal inflammation. They contain a low dose of a corticosteroid, a type of anti-inflammatory compound that reduces swelling, mucus production, and the immune overreaction that causes allergy symptoms. Common active ingredients include fluticasone and budesonide, both available over the counter in many countries.
Unlike decongestants, steroid sprays are designed for daily, long-term use. They don’t provide instant relief. Most people notice improvement after a few days of consistent use, with full effect building over one to two weeks. A typical starting dose is one spray in each nostril once daily, though this can be increased. The amount of steroid delivered per spray is tiny, measured in micrograms, and very little is absorbed into the rest of your body.
Antihistamine Sprays
Antihistamine nasal sprays contain ingredients like azelastine or olopatadine. These block histamine receptors inside your nose, which are the receptors that trigger sneezing, itching, and a runny nose when you encounter an allergen. They work faster than steroid sprays, often within 15 to 30 minutes.
Some products combine both approaches. One well-known combination pairs azelastine with fluticasone in a single spray, delivering antihistamine and anti-inflammatory action together. This can be more effective for moderate to severe allergies than either ingredient alone.
Saline Sprays
The simplest nasal sprays contain nothing more than salt water. Isotonic saline uses a 0.9% sodium chloride concentration, matching the salt level of your body’s own fluids. Hypertonic saline uses a higher concentration, typically around 3%, which draws extra moisture out of swollen tissue and can help loosen thick mucus. Studies have found both versions reduce allergy symptoms, with no significant advantage of hypertonic over isotonic for most people.
Saline sprays have no usage limits and no side effects to speak of. They’re often recommended as a first step before medicated sprays or as a daily rinse to clear out allergens and irritants.
The Inactive Ingredients
The active ingredient is only part of the formula. Every nasal spray also contains a carefully chosen set of inactive ingredients that serve specific purposes.
- Preservatives prevent bacteria and fungi from growing inside the bottle. Benzalkonium chloride and phenylethyl alcohol are the most common. These keep the solution sterile over weeks of repeated use, since the tip of the spray contacts your nose each time.
- Buffering agents maintain the solution’s pH level. Nasal sprays are formulated to fall between a pH of 4.5 and 6.5, which is the range that feels comfortable against the nasal lining and doesn’t irritate the delicate hair-like cells that sweep mucus through your sinuses.
- Viscosity modifiers adjust how thick or thin the liquid is. In steroid sprays, ingredients like microcrystalline cellulose keep the active ingredient evenly suspended so each pump delivers a consistent dose.
- Stabilizers and antioxidants prevent the active ingredient from breaking down over time. Chelating agents like edetate help with this by binding to trace metals that could trigger chemical reactions in the solution.
Some newer formulations also include mucoadhesive compounds, substances that help the spray cling to the moist nasal lining rather than dripping down your throat. Chitosan, a material derived from shellfish shells, is one of the most studied options. Modified versions of chitosan can stick to nasal tissue for hours, keeping the active drug in contact with the area it needs to treat.
Preservative-Free Sprays
Some people are sensitive to preservatives like benzalkonium chloride, which can cause dryness or irritation with long-term use. Preservative-free sprays solve this problem through clever engineering rather than chemistry. These pumps use a filter membrane that blocks bacteria from entering with outside air and a mechanical tip seal that prevents any liquid from flowing back into the bottle after each spray. Some designs use a collapsible inner pouch that shrinks as you use the spray, eliminating the need for outside air to enter the bottle at all. The fluid path inside the pump is also metal-free to prevent the formula from degrading through contact with iron-based components.
How the Spray Itself Works
The pump mechanism matters almost as much as what’s inside. When you press down on the actuator, a small piston forces a precise volume of liquid through a narrow nozzle, breaking it into a fine mist. The droplet size determines where the spray lands inside your nose. Too fine and it gets inhaled into your lungs. Too coarse and it drips right back out. Manufacturers calibrate the nozzle and pump pressure to produce droplets that deposit evenly across the nasal lining, which is where the blood vessels and mucous membranes can absorb the medication most effectively.