Homemade saline nasal rinse at 3 euros vs pharmacy spray

Saline solution at 3 euros versus branded spray: how to make homemade Rhinomer

A litre of saline solution costs about three euros at the pharmacy. A nasal spray with sterilised seawater costs considerably more. That price gap is what pushes half of Spain to make their own nasal rinse with a syringe, salt and water, and what has turned homemade Rhinomer into one of those topics that seem trivial until you work out what you spend per year.

The recipe that circulates is simple: 9 grams of salt per litre of water, the exact concentration of saline solution, or a teaspoon of sea salt per glass if you go by eye. Natural seawater, for comparison, contains 35 grams of salt per litre, four times more. That's why the commercial spray irritates some people and works for others.

Pharmacy saline solution: the cheapest and safest option

The most solid consensus on the matter doesn't involve mixing anything. It involves buying a 500-millilitre bottle or a litre of saline solution and drawing it out with a large syringe for nasal instillations. The price is around three euros per litre and lasts months. Compared with single-dose sachets and small containers, the saving is enormous.

The key is the concentration: 0.9 grams of sodium chloride per 100 millilitres, that is, the same 9 grams per litre. It's the solution hospitals use, suitable for mucous membranes and applied with pressure from squeezing the syringe. Those who have used it for years against stubborn sinusitis defend it without reservation: cheaper, impossible.

The problem with stored saline is another: bacteria can grow in an open container. The repeated recommendation is to sterilise the container and the water, or simply boil the water with the salt and let it cool before use.

Is nasal rinsing with tap water safe?

Here comes the serious warning. The US FDA has warned of sinus infections linked to nasal rinsing when the water is untreated, and the classic case is unboiled tap water. It's not a myth: there is official documentation on it, and there are accounts of people who rinsed their nose with unsterilised water ending up with an infected nose.

Home sterilisation has its technique. No violent boil is needed: three minutes at 70 degrees is enough, and bringing the water to the boil for a couple of minutes guarantees you've passed that threshold. Boiling seawater, on the other hand, solves nothing: as the water evaporates, the salt concentrates and the solution ends up stronger than it should be.

Seawater, Rhinomer and own-brand spray

The commercial container is, in essence, sterilised seawater. That explains why many wonder whether it's enough to grab a bottle at the beach, boil it and filter it. The short answer is that it's not worth it: the process concentrates the salt and doesn't remove all impurities. And if you live far from the coast, transport eats up the saving.

The middle alternative is supermarket own-brand sprays, with a different composition —2% seawater and lots of added salt— which dries out some people's nostrils more and even proves more effective for them. The propulsion system of the original container, with its rubber part, invites you to try refilling it, though it's unclear whether the one-way valve allows it.

Vicks VapoRub and eucalyptus steam: what users say

The decongestant repertoire doesn't end with saline. Vicks VapoRub has defenders who apply it to the chest before sleeping: body heat evaporates the product, which when inhaled dries the mucus and clears the airways. It's palliative, not a cure, and it avoids spending the night with a runny nose. Others prefer steam from boiled eucalyptus leaves, an all-time classic.

Hot water steam, with a towel over the head, appears as the safest and cheapest method of all: it kills bacteria and softens mucus without buying anything. With essential oils, the warning is not to overdo it, because they create dependency.

With all this, the branded nasal spray industry has a price problem that's hard to defend. What's less clear is that the homemade solution is always just as safe: the difference between a litre of saline at three euros and unboiled tap water is, literally, an infection.