How to read allergen labels: food and cosmetics

For someone with an allergy the label is not a curiosity but a decision tool. Whether a word is printed in bold, or whether a name added at the end of a list gets noticed, changes the whole shop. The good news is that this information is not placed at random: in both food and cosmetics, where an allergen must be written, in what form and above which threshold, is set by rules. So someone who knows the rules does not have to read a long list from beginning to end. They look straight at the place that matters.

All 14 groups that must be declared in food

• Cereals containing gluten: wheat, barley, rye, oats and products made from them such as semolina, bulgur, couscous and malt.
• Crustaceans: prawns, crab, lobster and sauces made from them.
• Eggs: frequently met in mayonnaise, ready desserts and baked goods.
• Fish: can be present in fish sauce, surimi and some instant soup mixes.
• Peanuts: common in chocolate, crackers and ready snacks.
• Soy: across a very wide range, as soy lecithin, soy protein and soy sauce.
• Milk: including lactose, casein, whey and butter derivatives.
• Tree nuts: hazelnut, almond, walnut, pistachio, cashew, Brazil nut, macadamia and pine nut.
• Celery: as root and stalk, in instant soups and spice mixes.
• Mustard: in sauces, pickles and marinades.
• Sesame: broad use including tahini, sesame bread and simit.
• Sulphur dioxide and sulphites: above a set threshold, with dried fruit and wine as the classic address.
• Lupin: used as flour in some gluten-free products.
• Molluscs: mussels, squid, octopus and their processed forms.

What these 14 groups share is that they must be emphasized wherever they appear in the list, using bold type, capitals or a different typeface. The emphasis rule does not apply only to prepacked products. In non-prepacked sales such as bakeries, delicatessen counters and loose goods, allergen information is expected to reach the consumer as well, although there it is often given on a written notice or verbally on request. Asking when buying non-prepacked goods is the behaviour that stands in for reading a label.

Allergy, intolerance and irritation are not the same

To read a label correctly you first need to know which problem you are dealing with, because the three work through different mechanisms and call for different solutions. In an allergy the immune system is involved, and even very small amounts can trigger a response. In an intolerance the mechanism is enzymatic or digestive. The amount is usually decisive there, and a small quantity may cause no trouble. Cosmetics have a parallel distinction: contact allergy is immune-driven and usually appears some time after contact, while irritation is direct and dose-dependent and can occur in most people at a sufficient concentration.

The legal standing of the 'may contain' warning

The distinctive thing about this phrase is that it is voluntary. A manufacturer must declare an allergen put into the recipe; declaring the possibility of carry-over from the production line is not a single rule imposed by legislation. That has two practical consequences. First, the wording varies from brand to brand: 'may contain traces', 'processed in the same facility' and 'may contain' all convey the same uncertainty. Second and more importantly, the absence of a warning is not proof that no cross-contamination occurred. Some manufacturers do not print the phrase at all. So with severe allergies, asking the manufacturer or sticking to products known to be safe is a firmer route than leaning on the label alone.

What does a gluten-free claim say?

The gluten-free statement is also legally defined, and it rests on a measurement: the product may contain at most 20 milligrams of gluten per kilogram. 'Very low gluten' points to a higher threshold (100 milligrams per kilogram) and is not the same thing. Oats are a special case here. Oats themselves contain no gluten, but because they can mix with wheat in the field and at the mill, someone with coeliac disease chooses only oats labelled gluten-free. Coeliac disease, wheat allergy and gluten sensitivity are different conditions, and which one applies and what diet to follow is determined by a doctor's assessment. This article only explains how to read the label.

How allergen declaration works in cosmetics

Cosmetics have no 'emphasized wording' rule like food, because listing every component by its INCI name is compulsory in any case. A special rule does apply to fragrance components, though. Even though parfum appears as a single word, known fragrance allergens must also be listed by name once they exceed a set concentration. The thresholds vary by product type: 0.001 percent in leave-on products and 0.01 percent in rinse-off ones. The EU expanded this list in 2023, and during the transition periods we will see both old and new labels side by side on the shelves. One more point is worth adding. 'Hypoallergenic' is not a legally defined assurance but a description of the manufacturer's intent.

• Fragrance allergen names cluster at the end of the list, in the same area as preservatives; once it becomes a habit your eye goes straight there.
• Natural essential oils also carry fragrance allergens; a product containing lavender or citrus oil does not count as fragrance-free.
• Hair dyes carry a mandatory warning text, and the advice to run a sensitivity test before colouring is part of that text.
• Metal allergens such as nickel do not appear in the ingredient list; they can come from raw material impurities or from the packaging.
• Different scented variants of the same brand carry different allergens; the fragrance-free version has to be assessed as a separate product.

Technical names an allergen hides behind

Allergen information can sit in three separate places

• Inside the ingredient list, through the emphasis on the substance's own name.
• In a short 'contains' summary placed just below the list.
• In a voluntarily added 'may contain' or 'processed in the same facility' line.
• In non-prepacked sales, on a sign, on a product card or verbally from the staff.

One frequent cause of recalls: an undeclared allergen

Anyone who follows food recall notices sees not only microbiological findings on the list, but also products where an allergen was found that the label did not declare. The cause is usually not bad faith. It is the realities of production: the recipe changes while old packaging stock continues to be used, a line is skipped while translating an imported product, or one of two products made on the same line carries over into the other. The practical consequence for you is this: for someone with an allergy, reading labels is not a one-off lesson but a repeated habit. If the packaging design of a product you buy regularly has changed, that is reason enough to read the list again.

Dietary preference labels are not an allergen assurance

Vegan, vegetarian, gluten-free and lactose-free statements answer different needs, and none of them amounts to an allergen assurance in itself. A vegan product contains no milk or egg by definition, but if it is made in the same facility the possibility of carry-over remains. On top of that, soy, peanuts and tree nuts are widely used in these products. A lactose-free product keeps its milk protein. It is therefore not suitable for someone with a milk allergy. The gluten-free statement is a stronger assurance than the others because it rests on a measured threshold, but it applies only to gluten. Cosmetics show a similar picture: a product labelled vegan or natural is not obliged to be safer than others in terms of fragrance allergens, because plant extracts themselves carry those components.

The same confusion arises with 'free from' phrases. A product saying 'milk free' does not mean it has been verified as safe for someone with a milk allergy, because the phrase concerns the recipe rather than the production environment. For allergens the binding information is not the claim on the front. It is the emphasis inside the ingredient list, and the warning line if there is one. If doubt remains, asking the manufacturer's customer line gives you a faster and more definite answer than guessing; most brands keep records that let them reply batch by batch.

How to use the label after a reaction

The most useful thing to do after a reaction is to keep a record rather than guess at the culprit. Keep the packaging of whatever was eaten or applied, note the date and time, and write down how long afterwards the reaction began. In cosmetics, the number of new products started in the same week matters too, because when three are trialled together the culprit stays unclear. When you visit a doctor these notes turn into information that directly helps a patch test or an allergy assessment, and the batch details may be asked for as well as the product name. What is described here is general information. Decisions about diagnosis and treatment belong to your doctor.

A 30-second check at the shelf

• In food, run your eye over the list to catch the emphasized words, then read the whole thing if you need to.
• Assess the allergen declaration together with the warning line just below the ingredient list.
• In cosmetics, focus on the last third of the list; fragrance and preservative names gather there.
• When you see a technical name you do not recognise, verify its source rather than guessing.
• Even if you have used a product without trouble before, read the list afresh when the pack says 'new formula'.

Common mistakes

• Reading 'natural' and 'plant-based' as an assurance that there are no allergens.
• Assuming that the imported and domestically made versions of the same product share the same recipe.
• Eliminating a whole product category in cosmetics without identifying the substance you react to.
• Reading allergen information from the front of pack only; the real information sits inside the list on the back.
• Thinking there is no point asking in a restaurant or bakery because there is no packaging.

Who does this matter for?

These rules make life easier above all for people with a diagnosed allergy and those close to them. For parents of school-age children, teaching the child to read the label matters as much as reading it yourself, because in time the child will make their own decisions. For people who often eat away from home the real skill is asking. With non-prepacked food the information usually sits with the staff rather than on a sign. On the cosmetics side, for anyone with recurring redness, itching or swollen eyelids, reading labels is the way to turn patch test results into practice; our sensitive skin guide goes into this separately. With severe allergies, reading labels does not replace a treatment plan. Emergency medication and the route to follow are set together with your doctor.

In long lists it is easy to miss something. Instead of reading the label by eye you can scan the product, and look up a substance you do not recognise on our Discover page. We gathered the general logic of these lists in our guide to reading ingredient lists.