The short answer (prices checked 14 October 2026)
- Cheapest per millilitre: Sterimar Congestion Relief Hypertonic with Copper, 100ml for £7.47. That is 7.5p a millilitre. It is sea water, not a decongestant, so the seven day limit below does not apply to it.
- The one Britain is buying: Sudafed Blocked Nose Spray, 15ml for £4.47, which is 29.8p a millilitre. It sat at number 11 in the whole Health & Personal Care chart when we looked. A full seven day course at the maximum dose in its licence uses 5.88ml, so £1.75 of the bottle.
- Dearest per millilitre: BHM NoriZite Kids, 20ml for £16.49, or 82.5p a millilitre. That is eleven times the Sterimar. It is also the only pick here aimed at children, who cannot be given a decongestant spray at all under six.
- The audit finding: of the first 20 unsponsored Amazon UK results for “nasal spray blocked nose”, 7 state a limit on how many days you can use the spray. Every one of those 7 says seven days. The NHS page for England says five. Not one of the 20 prints its licence number.
Cold season arrived and the chart moved with it. On 14 October 2026 the Sudafed Blocked Nose Spray was sitting at number 11 across the entire Health & Personal Care department on Amazon UK, which is the sort of rank a department usually reserves for vitamins and protein powder. Search the same shelf and you get something odd. The first page mixes licensed medicines with two completely different active ingredients, a steroid for hay fever, sea water, a “natural barrier” for children and an essential oil. They all say blocked nose. They are not the same kind of thing at all, and the rules about how long you may use them are not even close to each other.
So this page does two jobs. It works out what each bottle costs per millilitre and, for the decongestants, what one full course at the maximum dose in the licence actually costs. And it reads the licences, because the day limit is where the real story is.
Prices in this table come live from Amazon and can change through the day. Prices quoted in the text were checked by Look Into on 14 October 2026, so the two can differ.
As an Amazon Associate I earn from qualifying purchases. (paid link)
Prices and specs last checked by Look Into on 14 October 2026 · next check 9 December 2026 · how we picked
Five days or seven? England, Scotland and the licence do not agree
Start with the licence, because that is the document the pack is built from. We opened two Summaries of Product Characteristics on the electronic medicines compendium on 14 October 2026.
- Sudafed Blocked Nose Spray, xylometazoline hydrochloride 0.1% w/v, PL 15513/0074. Section 4.4 says “Use for more than seven consecutive days is not recommended.” Section 4.2 gives 0.14ml per metered spray.
- Otrivine Congestion Relief 0.1% Nasal Spray, xylometazoline hydrochloride 1mg/ml, PL 44673/0151. Section 4.4 says “This medicine should not be used for more than seven consecutive days” and warns that “prolonged or excessive use may cause rebound congestion and/or atrophy of the nasal mucosa.”
Seven days, then, twice over, from two different licence holders. Now read the NHS. The page at nhs.uk on decongestants, last reviewed 3 November 2022, says “Decongestant nasal sprays and drops should not be used for more than 5 days at a time”, and adds that using them for too long “can make your stuffiness worse”. The equivalent page on NHS inform in Scotland, last updated 31 May 2024, says “Decongestant nasal sprays shouldn’t be used for more than a week at a time”, which is seven.
Two national health services, one border, two numbers. England’s advice is two days stricter than the licence the pack is sold under. Scotland’s matches it. In January 2026 the Royal Pharmaceutical Society went public asking for the seven day limit to be made unmissable on packaging, after a survey of its own members, and its wording was seven days in a row for sprays containing xylometazoline or oxymetazoline. So the professional body, the licences and Scotland line up on seven, and the most-read health page in the country says five.
We are not going to tell you which number to follow. A pharmacist is the right person for that, and there is one in every shop that sells these. What we will say is that neither number reaches the shelf. Of the first 20 unsponsored listings, 13 say nothing at all about a day limit.
Three legal classes, one search result
The day limit only bites on one of the classes on that shelf, which is why the mixture matters. The Human Medicines Regulations 2012, regulation 2(1), define a medicinal product as a substance “presented as having properties of preventing or treating disease”, or one that may be administered “with a view to restoring, correcting or modifying a physiological function by exerting a pharmacological, immunological or metabolic action”. A decongestant spray narrows the blood vessels in your nose. That is a pharmacological action, so it is a medicine, and it carries a PL number.
The Medical Devices Regulations 2002, regulation 2(1), define a medical device as an article intended for “diagnosis, prevention, monitoring, treatment or alleviation of disease” which “does not achieve its principal intended action in or on the human body by pharmacological, immunological or metabolic means, even if it is assisted in its function by such means”. A hypertonic sea water spray works by drawing fluid across a membrane. That is physics, not pharmacology, and it is why those bottles sit on the device side of the line, with no PL number and no seven day cap.
Then there is a third thing, a steroid. Beconase is beclometasone dipropionate, a licensed medicine like the decongestants but on a different clock entirely. It is intended for allergy, it takes days rather than minutes to do much, and the seven day rule is not its rule. Three classes, one page of search results, and the listings do not tell you which one you are putting in the basket. None of the 20 we read used the words “medical device” and none printed a licence number.
One more thing worth recording, because we found it by reading the document rather than the pack. The Sudafed Blocked Nose Spray licence gives its dose twice and the two lines do not match. One says one spray into each nostril two to three times daily. The other says “Maximum daily dose: 3 sprays in 24 hours”. Those cannot both be the ceiling. We have used the first reading for the cost figures below, because it is the one the pack directions follow, and we have left the question open rather than settling it ourselves.
How we picked these
Six picks, chosen to cover the classes rather than to fill a list. We read the first 20 unsponsored results on amazon.co.uk for “nasal spray blocked nose” on 14 October 2026, opened every product page we shortlisted, and took the title, the pack size and the buy box price from the listing itself on that date. Prices below are what we read on 14 October 2026, not live figures. The comparison table further down the page pulls Amazon’s own feed and can sit off the buy box.
Cost per millilitre is the price divided by the pack size the listing states. Cost per seven day course is 0.14ml a spray, six sprays a day, seven days, which is 5.88ml, priced at that bottle’s own cost per millilitre. We only give that figure where we have read the metered volume in the product’s own licence, so two of the six cells are filled and the rest are empty. Beconase states a spray count and no volume, so it gets a cost per spray and no cost per millilitre. Look Into has not handled these products: every figure comes from the maker, the listing or a named source, read on the date shown. This page is a cost and labelling audit, not medical advice.
How they compare
| Spray | Legal class | Pack | Price on 14 Oct 2026 | Per ml | One 7 day course at max dose |
|---|---|---|---|---|---|
| Sterimar Congestion Relief Hypertonic with Copper | Sea water, device side of the line | 100ml | £7.47 | 7.5p | No day limit applies |
| Sudafed Blocked Nose Spray | Medicine, xylometazoline 0.1% | 15ml | £4.47 | 29.8p | £1.75, and the bottle holds 2.6 courses |
| Vicks Sinex Soother | Medicine, oxymetazoline | 15ml | £4.75 | 31.7p | Not given, see note |
| Otrivine Congestion Relief Fine Mist | Medicine, xylometazoline 0.1% | 10ml | £4.75 | 47.5p | £2.79, and the bottle holds 1.7 courses |
| Beconase 8-in-1 Hayfever Relief | Medicine, beclometasone dipropionate | 100 sprays, no volume stated | £4.99 | Not stated on the listing | Different rules, 40p a day at its own 8 spray maximum |
| BHM NoriZite Kids | Barrier spray, no class printed | 20ml | £16.49 | 82.5p | No day limit applies |
The six we would buy
Sterimar Congestion Relief Nasal Spray, Hypertonic with Copper, 100ml
£7.47 for 100ml is 7.5p a millilitre, which makes this the cheapest nose on the page by a factor of four against the medicated bottles and eleven against the dearest. It is sea water made hypertonic, plus copper, and the listing is unusually frank about what that means: “free from steroids, drugs and preservatives”, which is the device argument in plain words. It claims up to six hours of decongestion and says it suits adults and children of three and over, pregnancy and breastfeeding included. Because nothing in it acts pharmacologically, the seven day ceiling in the decongestant licences has nothing to attach to.
The catch: it works by osmosis, so it is slower and gentler than a vasoconstrictor and it will not clear a blocked nose in two minutes. The listing also never says what it legally is. There is no device registration number and no class on the page, so you are taking “free from drugs” on trust.
Sudafed Blocked Nose Spray, 15ml
£4.47 for 15ml, or 29.8p a millilitre, and on 14 October 2026 it was number 11 across the whole Health & Personal Care department, which is the highest-ranked nasal product anywhere in that chart. The active is xylometazoline hydrochloride 0.1% and its licence is PL 15513/0074. At 0.14ml a spray and six sprays a day, a full seven day course draws 5.88ml, so £1.75 of this bottle, and 15ml is about two and a half courses. The listing promises work in two minutes and up to ten hours, which is the behaviour of a vasoconstrictor rather than a wash.
The catch: the day limit is on the page but buried, as “Continuous use for over 7 days is not recommended” down in the detail rather than anywhere you would see it before buying. And the licence contradicts itself: one line gives one spray in each nostril two to three times daily, another gives a maximum daily dose of three sprays in 24 hours. Those are not the same ceiling, and we have not resolved which the manufacturer means.
Vicks Sinex Soother Decongestant Nasal Spray, 15ml
£4.75 for 15ml is 31.7p a millilitre, a shade more than the Sudafed for the same volume. The active here is oxymetazoline rather than xylometazoline, the other decongestant the Royal Pharmaceutical Society named in January. What earns it a place is the labelling. It is one of only seven listings in twenty that mention a day limit at all, and the only one that puts it in plain sight twice, as “Not to be used longer than 5-7 days in a row”. It also tells you to consult a doctor or pharmacist if you feel worse or no better after three days, which is more use than most of the shelf manages.
The catch: “5-7 days” is a range where the licences we read give a number, so even the best label on this shelf leaves you to pick. We did not open this product’s own licence, so the cost per course column is empty for it rather than guessed from a different product’s metered dose.
Otrivine Congestion Relief Nasal Spray, Fine Mist, 10ml
£4.75 for 10ml makes this the dearest medicated millilitre here at 47.5p, and one bottle covers only about one and a half full courses. It earns its place because its licence, PL 44673/0151, is the document that states the position most plainly: “This medicine should not be used for more than seven consecutive days”, with a warning that prolonged or excessive use may cause rebound congestion and atrophy of the nasal mucosa. The listing repeats the limit three times in different words, which is the best any listing on this shelf does. One application in each nostril up to three times a day, 0.14mg of xylometazoline per spray.
The catch: you pay 60 per cent more per millilitre than the Sudafed for the same active at the same strength, and the small bottle is the reason. If you are going to buy a decongestant at all, the 15ml packs are better value for an identical course.
Beconase 8-in-1 Hayfever Relief Nasal Spray, 100 sprays
£4.99 for 100 sprays is 5.0p a spray. The active is beclometasone dipropionate, a corticosteroid, and the listing sets its own ceiling at eight sprays and 400 micrograms a day, so the pack holds about twelve and a half days at full dose and costs 40p on the day you use the most. That is the cheapest full day of any licensed medicine on this page. It belongs here as the contrast: a steroid for allergic congestion is a medicine like the decongestants but on a completely different clock, and the seven day rule is not its rule.
The catch: it is a hay fever spray and will do very little for a cold in the next ten minutes, because steroids take days to build an effect. The listing gives a spray count and no volume at all, so there is no honest way to put it in the cost per millilitre column with the other five.
BHM NoriZite Nasal Spray Kids, 20ml
£16.49 for 20ml is 82.5p a millilitre, eleven times the Sterimar and the most expensive bottle on this page by a long way. It is on the list because of the gap it sits in. The NHS says decongestants should not be given to children under six, and between six and eleven should not run past five days, so for a congested four year old the whole decongestant shelf is closed. This is a barrier spray instead, built on polysaccharides, described as drug-free and hormone-free and aimed at children from three to twelve.
The catch: the title claims “Scientifically Proven 6+ Hrs Protection” and the listing does not name the study, so there is nothing a buyer can go and read. As with the Sterimar there is no device registration or class printed either. You are paying the highest price per millilitre here for the thinnest paper trail.
Two of the six moved between Amazon’s own product feed and the buy box on the day we looked. The live table above pulled £7.74 for the Sterimar against a £7.47 buy box, and £5.51 for the Beconase against £4.99. The prices in the cards and the table of figures are the buy box ones, read on 14 October 2026, because that is what you pay at the till. The live table is Amazon’s feed and can sit either side of it.
What 20 listings actually tell you
We read the first 20 unsponsored amazon.co.uk results for “nasal spray blocked nose” on 14 October 2026 and counted, looking only at the product title, the bullet points, the product description, the product details, the important information panel and the technical specification table. Nothing from reviews, nothing from the images.
- 7 of 20 state a limit on how many consecutive days you may use the spray. 13 say nothing about it.
- Of those 7, every single one says seven days. Two of them give it as a range, “5-7 days in a row”. Not one listing states the five day figure that nhs.uk gives.
- 0 of 20 print a licence number, so there is no way from the listing to find the Summary of Product Characteristics the day limit comes from.
- 0 of 20 use the words “medical device”, even though several of them are describing products that sit on that side of the line.
- 11 of 20 name an active or principal substance. 19 of 20 give a pack size in millilitres and 2 of 20 give a spray count, which is why the cost columns above are not all comparable.
- 6 of 20 mention a pharmacist. 8 of 20 mention pregnancy. 2 of 20 mention an age floor.
Put the two halves together and the shape of the problem is clear. The licences and the professional body say seven days, the NHS page for England says five, and on the shelf two out of three listings do not raise the question at all. The cheapest bottle per millilitre on this page is the one that the day limit does not apply to, and the dearest is the one aimed at the age group that is not allowed a decongestant in the first place.
Questions people ask
How many days can I use a decongestant nasal spray for?
The two licences we read both say no more than seven consecutive days, and the Otrivine one warns that going beyond that may cause rebound congestion and atrophy of the nasal mucosa. The NHS page for England says five days. NHS inform in Scotland says a week. If you want one number for your own situation, ask the pharmacist in the shop you are buying it from, because they can see the pack and you can tell them what else you take.
What is the difference between a decongestant spray and a sea water spray?
A decongestant narrows the blood vessels in the lining of your nose, which is a pharmacological action, so under regulation 2(1) of the Human Medicines Regulations 2012 it is a medicinal product and carries a licence number. A hypertonic sea water spray draws fluid out of the lining by osmosis, which is not pharmacological, so it falls under the medical device definition in regulation 2(1) of the Medical Devices Regulations 2002 instead. That is the whole reason one of them has a seven day ceiling and the other does not.
Which nasal spray is cheapest?
Per millilitre, the Sterimar Congestion Relief 100ml at 7.5p, from a spread that runs to 82.5p for the NoriZite Kids. Per course of treatment, the comparison changes shape, because a decongestant is used for a week at most and a sea water spray can be used for as long as you like. The Sudafed uses £1.75 of its bottle over a full seven days at the maximum dose, which is the cheapest licensed course here.
Can children use a decongestant nasal spray?
Not under six. The NHS page says decongestants should not be given to children under six years of age, and that those aged six to eleven should not take them for longer than five days. Both NHS pages we read agree on the under-six floor. The sea water and barrier sprays on this page state lower age floors on their own listings, three and over in both cases, and neither is a decongestant.
Sources
- Summary of Product Characteristics, Sudafed Blocked Nose Spray, PL 15513/0074, electronic medicines compendium
- Summary of Product Characteristics, Otrivine Congestion Relief 0.1% Nasal Spray, PL 44673/0151, electronic medicines compendium
- NHS, Decongestants, last reviewed 3 November 2022
- NHS inform Scotland, Decongestants, last updated 31 May 2024
- The Human Medicines Regulations 2012, regulation 2, definition of a medicinal product
- The Medical Devices Regulations 2002, regulation 2, definition of a medical device
- The Pharmaceutical Journal, Risks of nasal decongestant spray overuse need to be made clearer, says RPS, 8 January 2026
Prices and chart positions were read on amazon.co.uk on 14 October 2026 and will have moved since. Look Into has not handled these products: every figure comes from the maker, the listing or a named source, read on the date shown. This page is a cost and labelling audit and is not medical advice, so speak to a pharmacist or your GP about what to use and for how long. Look Into is a participant in the Amazon EU Associates Programme and earns from qualifying purchases made through links on this page, at no extra cost to you.