Ingredients Explained

What the technical names on the back of the pack are actually doing.

An ingredient list is a functional document. Every entry is there to do a job: hold an emulsion together, stop a fat going rancid, keep a cream free of bacteria, carry a flavour, thicken a sauce. Almost nothing is on a label by accident.

This guide explains how the two ingredient systems you meet every day work: E numbers on food, INCI names on cosmetics, and what the main families of additives do, and how Sláinte decides whether an ingredient counts against a product.

Illustration of laboratory flasks and droppers beside a food jar

An E number is an approval, not a warning

The E in an E number simply means the additive is approved for use in the European Union. Approval follows a safety assessment by the European Food Safety Authority, which sets an acceptable daily intake where one is needed and defines the foods the additive may be used in and the maximum amount permitted. The full list is published in Regulation (EC) No 1333/2008 and its annexes.

The numbering is not random either. Additives are grouped by function, which means the first digit tells you roughly what an unfamiliar number is doing before you look it up.

How E numbers are grouped

Range	Family	Job on the label
E100–E199	Colours	Restore or add colour lost in processing
E200–E299	Preservatives	Prevent mould, yeast and bacterial spoilage
E300–E399	Antioxidants and acidity regulators	Stop fats oxidising; control pH and tartness
E400–E499	Thickeners, stabilisers, emulsifiers	Control texture and stop separation
E500–E599	Anti-caking agents and raising agents	Keep powders loose; make baked goods rise
E600–E699	Flavour enhancers	Increase savoury intensity, such as glutamates
E900–E999	Glazing agents and sweeteners	Coatings, foaming control, intense sweeteners
E1000–E1599	Modified starches and additional additives	Texture, stability, carriers for flavours

The families you meet most often

Emulsifiers

Fat and water separate. Emulsifiers keep them mixed. Lecithins (E322) are the most common example and are usually derived from soya or sunflower, which is why they carry an allergen emphasis on many labels. Mono- and diglycerides of fatty acids (E471) do the same job in baked goods and spreads. Emulsifiers are not a nutritional problem in themselves; they are a signal that the product is an engineered mixture rather than a simple food.

Preservatives

Sorbates (E200–E203), benzoates (E210–E213) and sulphites (E220–E228) suppress microbial growth. Sulphites matter for a specific reason: above 10 mg/kg they must be declared as an allergen because they trigger reactions in some people with asthma. Nitrites (E249–E250) in cured meat have their own literature, and processed meat is treated differently from other categories for that reason.

Antioxidants

Fats go rancid on contact with air. Ascorbic acid (E300) and tocopherols (E306–E309) slow that down and are simply vitamin C and vitamin E doing chemistry. Rosemary extract (E392) does the same job from a plant. Synthetic phenolics such as BHA (E320) and BHT (E321) are more restricted, and BHT in particular is where cosmetics and food overlap.

Sweeteners

Intense sweeteners such as sucralose (E955), acesulfame K (E950), aspartame (E951) and steviol glycosides (E960) provide sweetness at a fraction of the weight of sugar. They are approved with an acceptable daily intake, and swapping sugar for them changes the sugar figure on the label without changing the fact that the product is a sweet one.

Flavour enhancers and flavourings

"Flavouring" and "natural flavouring" are legally defined but deliberately unspecific: the composition is not published. This is the one place where an ingredient list stops being informative, and no scoring system can see through it.

Tayto

Cheese & Onion Flavour Potato Crisps

Additives declared: E100 curcumin (colour, from turmeric), E160c paprika extract (colour), E392 rosemary extract (antioxidant)
Also inside the flavour bracket: onion powder, yeast powder, natural flavourings, dextrose, starch, cheese powder and yeast extract

All three additives here are plant-derived, and none of them are what limits the product. The energy density and salt of a fried crisp do that. Additives and nutrition are separate questions, and confusing them is the most common mistake in ingredient scoring.

Palm oil, lecithin and vanillin: reading a real list

A short list can still tell you a lot when you know what each entry is for. Nutella declares seven ingredients, and each one has a job: sugar for sweetness and bulk, palm oil for a solid-at-room-temperature texture that does not separate, hazelnuts and cocoa for flavour, milk powder for creaminess, lecithin to hold the whole thing together, and vanillin, a single flavour compound rather than vanilla extract, for aroma.

Nutella

26/ 100Poor

Sugar, palm oil, hazelnuts (13%), skimmed milk powder (8.7%), fat-reduced cocoa (7.4%), emulsifier: lecithins (soya), vanillin
56.3 g sugars and 10.6 g saturates per 100 g

Only one additive on the list, and it is a benign one. The score is driven almost entirely by the first two ingredients, which is usually how it works.

Whole Earth

Crunchy Peanut Butter

73/ 100Good

Roasted peanuts (97%), sustainable palm oil, sea salt
643 kcal, 3.8 g sugars, 7.9 g saturates, 6.7 g fibre, 27.7 g protein, 1.08 g salt per 100 g

Energy-dense and still a good score, because the energy comes with protein and fibre from the nut itself. Density and quality are not the same measurement, which is why a single-nutrient rule cannot rank food.

Cosmetics use a different system: INCI

Cosmetic ingredients are listed under the International Nomenclature of Cosmetic Ingredients, required across the EU by Regulation (EC) No 1223/2009. The conventions are different from food, and they change how the list should be read:

Ingredients are listed in descending order of weight, but only down to 1%. Below that threshold they may appear in any order.
Water is Aqua, and in most rinse-off products it is the first and largest ingredient by a wide margin.
Plants are given in Latin binomials, so sunflower oil appears as Helianthus annuus seed oil and almond oil as Prunus amygdalus dulcis oil.
Colourants sit at the end under CI numbers, outside the weight order entirely.
Parfum is a single word covering a mixture that is not disclosed. The twenty-six fragrance allergens that must be named individually: limonene, linalool, citronellol, geraniol, coumarin, hexyl cinnamal and the rest are the only part of a fragrance you get to see.

Illustration of an INCI ingredient list on a shampoo bottle viewed through a magnifying glass — INCI lists are ordered by weight only down to 1%. Everything below that can appear in any order.

Common INCI names and what they do

INCI name	Function	Worth knowing
Aqua	Solvent	Usually the largest ingredient in a wash or shampoo
Sodium laureth sulfate	Cleansing surfactant	Effective foaming cleanser; can be drying at high levels
Cocamidopropyl betaine	Secondary surfactant	Milder co-surfactant, a recognised contact allergen for some
Glycerin	Humectant	Draws water into the skin; very widely used
Phenoxyethanol	Preservative	Restricted to 1% in the EU; among the better-tolerated options
Methylisothiazolinone	Preservative	Restricted and banned in leave-on cosmetics in the EU
DMDM hydantoin	Preservative	Releases formaldehyde in use; restricted and must be labelled
Parfum	Fragrance	Undisclosed mixture; only named allergens are visible
Limonene / Linalool	Fragrance components	Declared because they are recognised contact allergens
BHT	Antioxidant	Stabilises fats and fragrance; restricted by concentration
Salicylic acid	Exfoliant / preservative	Active at low percentages; restricted in the EU
CI 77891	Colourant (titanium dioxide)	Pigment or opacifier, listed outside the weight order

Dove

Deep Clean Body Wash

15/ 100Bad

Aqua, sodium laureth sulfate, petrolatum, acrylates copolymer, parfum, cocamide MEA, hydrated silica, ammonium chloride, cera microcristallina, DMDM hydantoin, tetrasodium EDTA, methylisothiazolinone, and four CI colourants
Two restricted preservatives on one list: DMDM hydantoin and methylisothiazolinone

This is a formulation question, not a marketing one. Methylisothiazolinone is a well-documented contact sensitiser and is no longer permitted in leave-on cosmetics in the EU; DMDM hydantoin releases formaldehyde in use. Both are what cap this score, and both are visible on the label if you read to the end.

Clean & Clear

Blackhead Clearing Daily Scrub

45/ 100Poor

Aqua, cetyl alcohol, PPG-15 stearyl ether, cellulose, glycerin, polysorbate 60, salicylic acid, steareth-21, cera microcristallina, menthyl lactate, potassium cetyl phosphate, xanthan gum, disodium EDTA, BHT, parfum, CI 77510
One declared active, salicylic acid, plus a mild abrasive (cellulose) and an antioxidant (BHT)

A middling score for an understandable reason: nothing here is severe, but undisclosed parfum and a restricted antioxidant sit alongside an active that some skin tolerates poorly. The list is short enough to assess almost completely, which is more than most cosmetics allow.

How Sláinte assesses an ingredient

Every ingredient assessment in Sláinte answers the same six questions, in the same order, and the answer is written down before it can affect a score:

What it is: chemical or botanical identity, and its E number or INCI name.
Why it is used: the technical function it performs in that product.
Where it appears: the categories it is typically found in.
What the evidence says: regulatory status, restrictions, and documented effects.
What is uncertain: the limits of the evidence, stated plainly.
How it affects the assessment: none, minor, moderate or high concern.

Three rules that keep it honest

An unfamiliar name is not evidence. Tocopherol is vitamin E. Ascorbic acid is vitamin C. Sodium chloride is salt. Length and complexity of a name carry no information about risk.

Regulatory restriction is evidence. When a regulator restricts an ingredient to a maximum concentration, bans it in leave-on products, or requires it to be declared as an allergen, that is a documented position rather than an opinion, and it is what the assessment leans on.

No assessment is better than a guess. When Sláinte has no verified position on an ingredient, the app says so instead of inventing a rating. Some products therefore show ingredients marked as not yet assessed, and that is the intended behaviour.

The short version

An E number means an additive is approved in the EU, and the first digit tells you which job family it belongs to.
Additives and nutrition are separate questions; most poor scores are driven by the first few ingredients, not by the additives at the end.
INCI lists are ordered by weight only down to 1%, so everything after that point is unordered.
Parfum hides its composition; only the twenty-six declarable fragrance allergens are visible.
Restrictions set by regulators are the strongest evidence on a label, and unfamiliar chemical names are no evidence at all.