In-between nasal surgery cases today in the operating room, my resident asked me why the standard over-the-counter isotonic nasal saline preparation said .65% saline, rather than .9% saline.
The normal salt concentration in our bodies is 0.9%, which can also be mimicked by adding 9 grams of salt into 1 liter of water. This is called isotonic saline.
Nasal saline rinses are a helpful way of helping you to clear out your nose and open up your sinuses. There are a number of different concentrations, formulations, and ways of getting saline into your nose. Most physicians recommend isotonic saline, which is the same salt concentration as what’s in your body. There are certain reasons for use more or less concentrated versions.
Hypertonic saline is saltier than your body’s salt concentration, so irrigating your nose will cause water to leave your nasal membranes into the saline to equalize the salt concentrations. It’s like what happens when you add salt to a cucumber. Water leaves the cucumber and it shrivels up, like what happens to your nasal membranes. Swimming in ocean water also does the same thing. This process is called osmosis. Using hypotonic (less saltier) saline will cause water to enter your nasal membranes, causing more swelling and congestion.
In theory, you should use isotonic saline to flush out nasal mucous and cause some mild shrinkage of your nasal membranes. This is why nasal saline irrigation can make you feel and breathe much better. Then why do many products say that .65% is “isotonic”?
After doing some research, it turns out that one of the common brand names (Ayr®) is isotonic at .9%, but only .65% is salt. The rest is made up of a buffering agent (sodium hydroxide) to make it less irritating, with two other preservatives. The first one is EDTA, which acts to bind to heavy metals, and also has antibacterial and anti fungal properties. It’s also used in a number of other applications, as a food stabilizer to cosmetics and even for lead poisoning. The other one is benzalkonium chloride, which is used in many eye drops and nasal sprays as a preservative. It also has antimicrobial properties.
Neilmed®, on the other hand, comes in dry packets which you use to make your own isotonic saline. It contains only sodium chloride and sodium bicarbonate.
If you also look at the list of ingredients for Ayr gel, it contains a lot more ingredients that you may normally see in hand lotions:
- methyl gluceth-10
- propylene glycol
- aloe barbadensis leaf juice (aloe vera gel)
- PEG/PPG-18/18 dimethicone
- sodium chloride
- xanthan gum
- glyceryl polymethacrylate
- sodium hydroxide
- poloxamer 184
- diazolidinyl urea
- glycine soja (soybean) oil
- geranium maculatum oil
- tocopheryl acetate
- blue 1.
This may explain why I personally can’t tolerate any kind of nasal saline, since it burns too much, even with added buffering agents. However, most people do well with nasal saline irrigation.
There’s also some concern about long-term use of nasal saline, but for short bursts or intermittent use, it should be safe.
The least expensive way is to make your own saline. Mix 2 cups of distilled water or boiled tap water that’s been cooled to lukewarm temperature with one teaspoon of sea salt or Kosher salt and one teaspoon of baking soda. Don’t use regular table salt, as it may contain iodine. You can recycle one of the over-the-counter bottles or containers, or even use a very large medical syringe or even a turkey basting syringe. Baby suction bulbs can also work. You can store homemade saline at room temperature for 3 days.
The bottom line is that not all saline is the same. If you walk down the aisle in the pharmacy, you’ll see many more options. Take a look at all the ingredients. Not only are the ingredients different, the way you get the salt water into your nose is also different. This ranges from squeeze bottles, to Neti-pots, and syringes, and even aerosol cans. There are even pressurized irrigation systems.
What you’re experience with nasal saline washes? Are you sensitive to various added ingredients? If you make your own, what helpful tips can you offer? Please enter your experiences and suggestions in the text box below.