You can make a povidone-iodine nasal spray at home by diluting a standard 10% povidone-iodine solution with sterile saline to reach a safe concentration of 0.5% to 1.25%. The process takes about five minutes and requires only a few inexpensive supplies. Getting the dilution right is the most important step, since concentrations above 2.5% can damage the delicate lining inside your nose.
What You Need
The base ingredient is 10% povidone-iodine solution, which is widely available at pharmacies. This is the same brown antiseptic liquid sold under brand names like Betadine. Do not use tincture of iodine, which contains alcohol and will burn nasal tissue. Lugol’s iodine is sometimes discussed as an alternative, but povidone-iodine is far more studied for nasal use and is the standard in clinical trials.
You also need:
- Sterile or distilled water. Use store-bought water labeled “distilled” or “sterile,” or boil tap water for at least one minute and let it cool completely. The CDC warns that rinsing sinuses with untreated tap water carries a rare but fatal risk of infection from waterborne parasites like Naegleria fowleri.
- Non-iodized salt (optional, for making saline). Pre-made sterile saline works too.
- A clean nasal spray bottle. Empty 30 mL spray bottles are sold at most pharmacies or online.
- A measuring syringe or teaspoon for accurate dilution.
How to Dilute to a Safe Concentration
Clinical trials testing povidone-iodine nasal spray for viral prevention typically dilute the standard 10% solution at a ratio of 1:30, which produces a concentration of roughly 0.33%. A review published in Ear, Nose & Throat Journal confirmed that concentrations up to 1.25% are safe for nasal use for periods up to five months, and that concentrations below 2.5% do not reduce ciliary beat frequency or cause damage to nasal cells. Staying at or below 0.5% gives you a comfortable margin of safety.
To make approximately 30 mL of 0.5% povidone-iodine spray:
- Measure 1.5 mL of 10% povidone-iodine solution (about one-third of a teaspoon).
- Add it to 28.5 mL of sterile saline or distilled water.
- Gently swirl or shake to mix. The liquid should be a light amber or weak tea color.
For a 0.33% solution (matching the 1:30 dilution used in clinical trials), use 1 mL of 10% povidone-iodine in 29 mL of saline. If you prefer the upper safe limit of 1.25%, use 3.75 mL of 10% solution in 26.25 mL of saline. A small oral syringe makes measuring these volumes much easier than eyeballing with a spoon.
Making the Saline Base
If you’re making your own saline rather than buying pre-made, dissolve about one-quarter teaspoon of non-iodized salt in 8 ounces (240 mL) of your sterile or distilled water. This creates an isotonic solution that matches your body’s salt concentration and won’t sting or irritate your nasal passages. You only need 30 mL or so per batch of spray, so you’ll have saline left over. Store the extra in a clean, sealed container in the refrigerator and use it within 24 hours.
How to Use It
In clinical trials with healthcare workers, povidone-iodine nasal spray was used two to three times per day: once at the start of the workday, once midday, and once at the end. Each application involved two to three sprays per nostril. Tilt your head slightly forward, insert the nozzle just inside one nostril, spray, then sniff gently so the mist reaches deeper nasal surfaces. Repeat on the other side. Some people follow this with a povidone-iodine gargle at the same concentration to cover the throat.
The solution works quickly. Povidone-iodine is virucidal within 15 to 60 seconds of contact. You don’t need to leave it sitting in your nose for extended periods. A gentle sniff after spraying is enough to distribute it across nasal surfaces.
Storage and Shelf Life
Once you dilute povidone-iodine, the solution is less stable than the concentrated original. Make small batches, enough for a few days at most, and store the spray bottle in a cool, dark place. If the solution loses its amber color and turns clear or very pale, the active iodine has degraded and the solution should be replaced. The undiluted 10% povidone-iodine bottle has a long shelf life on its own, so it’s more practical to mix fresh diluted spray every few days than to make large quantities.
Always label your spray bottle clearly with the concentration and the date you mixed it.
Safety Considerations
Povidone-iodine nasal sprays at concentrations below 1.25% have a strong safety profile. Research shows no impact on thyroid function, mucociliary clearance, or sense of smell at concentrations as low as 0.08%, even with extended use. A Phase III clinical trial tested a branded 0.5% povidone-iodine nasal spray and found no ciliotoxic or cytotoxic effects after up to 30 minutes of exposure in human nasal cell models.
That said, there are a few groups who should be cautious. People with known iodine or povidone allergies should avoid this entirely, though true iodine allergy is rare. Those with thyroid conditions, particularly hyperthyroidism, should be aware that iodine is absorbed through nasal membranes. Chronic use at concentrations up to 5% has not been shown to cause clinical thyroid disease in studies, but if you have an existing thyroid condition, it’s worth discussing with your doctor. Pregnant and breastfeeding women should also exercise caution, since iodine crosses the placenta and enters breast milk.
The most common side effect is mild stinging or a metallic taste in the back of the throat. Both tend to be brief. If you experience persistent irritation, burning, or swelling, stop using the spray. The brown tint can also temporarily stain skin around the nostrils, which washes off easily.