How to Spot Hidden Sulphites on a Label

Sulphites hide under several names and in places you would not expect. The names and E-numbers to look for, the usual hiding places, and the wine and medicine quirks to know.

Why sulphites are easy to miss

Sulphites appear under several different names and in foods you would never associate with preservatives, which is exactly why people miss them. They are used to keep colour, prevent browning and extend shelf life, so they turn up in things that look fresh and natural. A quick, systematic check fixes the problem, and this guide gives you one.

Step 1: Learn the names and E-numbers

Scan the ingredients for sulphur dioxide, sodium sulphite, sodium and potassium metabisulphite, sodium and potassium bisulphite, and the overall E-number range E220 to E228. Any one of these means sulphites are present. Because the same preservative can appear as a word on one packet and an E-number on another, it pays to know both forms, so “E223” does not slip past you just because the label avoided the word “sulphite”.

Write the full set of names on your guard list once, and you will recognise them on sight from then on.

Step 2: Check the usual hiding places

Sulphites concentrate in a handful of predictable categories: wine and beer, dried fruit, packet and instant potato products, pickles and pickled foods, bottled lemon and lime juice, some processed meats, and some soft drinks and cordials. If a product falls into one of these groups, read it carefully rather than assuming it is clear. The bright orange dried apricot is the classic visual giveaway of sulphiting, whereas duller, browner dried fruit is often unsulphured.

Step 3: Read “contains sulphites” on drinks

In the UK and EU, sulphites present above 10 milligrams per kilogram or 10 milligrams per litre must be declared, which is why so much wine carries the phrase “contains sulphites”. Treat that phrase as your flag. Bear in mind that even “no added sulphites” wine still contains a small amount that forms naturally during fermentation, so it is lower rather than truly sulphite-free.

Step 4: Check medicines and supplements

Sulphites are used as preservatives in some medicines, including certain liquid and injectable forms. If your reactions do not line up with anything you have eaten, your medicines and supplements are worth checking too. Read the patient information leaflet, and ask your pharmacist if you are unsure whether a product contains them.

Common mistakes

The usual slips are looking only for the word “sulphite” and missing the E-numbers, assuming fresh-looking foods like dried fruit or processed potato are additive-free, treating “organic” or “natural” wine as sulphite-free, and forgetting that eating out and salad bars can involve sulphites that never appear on a label you can read. Another is checking food but overlooking medicines.

How to tell it worked

Your checking is working when you can glance at a label or a menu and quickly place whether sulphites are likely, and when your reactions become rarer and easier to trace to a specific product. If you still react with no obvious source, widen the net to drinks, medicines and eating out rather than assuming your reading is at fault.

When to get help

Sulphite sensitivity can go beyond the skin. If you get wheezing, chest tightness or breathlessness after sulphites, especially if you have asthma, treat that as a medical matter and seek advice promptly. Any swelling of the lips, tongue or throat, or difficulty breathing, needs urgent help. For ongoing or unclear reactions, your GP can advise and refer you for allergy assessment. This guide is educational and is not medical advice.

Check products against your list

A free database like Open Food Facts lets you look up a product’s additives, and Fig is genuinely good for managing a defined eating pattern. These give broad information rather than a check against your own skin. To do it automatically, a personal-list app like ClearaScan lets you save sulphites, and all their names, once and scan any product, food, medication or cosmetic, against your ingredient guard list, flagging only yours. Its Reaction Journal lets you tie a flare back to the product that caused it, a shared Care Circle lets family scan for you, and a Trusted Products list keeps what you have cleared. It is currently in early access. (Disclosure: our editor co-founded ClearaScan, and we are not paid to mention the others.)

Written and reviewed by the Sensitive Skin Lab editorial team.