Maria Fernandez, Ingredients and Formulation Editor.
The back of a skincare bottle carries more useful information than the front, but almost nobody reads it carefully — and the people who do are often misled by what they find. Ingredient lists follow a precise regulatory format governed by the International Nomenclature of Cosmetic Ingredients, and understanding its conventions changes how you evaluate every product you pick up. A 2019 survey published in the Journal of Cosmetic Dermatology found that 73 per cent of consumers who said they read ingredient lists could not correctly identify whether a listed ingredient was present at a meaningful concentration or a trace amount.
- The one-per-cent line: ingredients above one per cent concentration must be listed in descending order; below it, they can appear in any sequence the manufacturer chooses.
- INCI names are not brand names: tocopheryl acetate is a form of vitamin E, not a synthetic additive — the Latin and chemical names are required by law.
- The ingredient list is a formula, not a ranking: position tells you relative concentration, but two adjacent ingredients can differ by a factor of ten.
The Descending Order Rule and Its Limits
EU Cosmetics Regulation 1223/2009 requires that ingredients be listed in descending order of concentration — but only above the one-per-cent threshold. Below one per cent, the manufacturer may list ingredients in any order. This creates a practical problem for consumers: everything after the one-per-cent line looks the same, whether it is present at 0.9 per cent or 0.001 per cent.
The one-per-cent line is not marked on the label. Experienced formulators estimate its position by looking for common one-per-cent markers: phenoxyethanol and other preservatives, xanthan gum, fragrance, and certain thickeners tend to cluster around one per cent in typical formulations. Anything listed after these markers is almost certainly present at a trace level.
Active Ingredients Versus Functional Ingredients
Consumers tend to scan for active ingredients — retinol, niacinamide, hyaluronic acid, vitamin C — but most of the formula by volume consists of functional ingredients that shape the product’s texture, stability and shelf life. Water is almost always first. Emollients like cetyl alcohol and dimethicone smooth the skin and help the product spread evenly. Emulsifiers hold oil and water phases together. Thickeners give the product body.
None of these functional ingredients are filler. Without them the active ingredients would separate, degrade, or sit on the surface of the skin without penetrating. A well-formulated moisturiser with 2 per cent niacinamide in a stable, elegant base will outperform a poorly formulated serum with 10 per cent niacinamide that degrades within weeks of opening.
What Concentration Actually Means
When a product advertises 10 per cent niacinamide or 20 per cent vitamin C, that number refers to the concentration of the named ingredient in the total formula — not its potency on your skin. A 20 per cent L-ascorbic acid serum at pH 3.5 in an anhydrous base is a very different proposition from a 20 per cent magnesium ascorbyl phosphate cream at pH 6. Both are vitamin C at 20 per cent. They behave completely differently.
Concentration without context is marketing. The relevant questions are: which form of the ingredient, at what pH, in what base, with what stabilisation, and does peer-reviewed evidence support this particular combination at this concentration? If the brand does not answer these questions, the percentage on the front of the box is decoration.
Preservatives: What to Look For
Every water-containing skincare product needs a preservation system to prevent microbial growth. The most common broad-spectrum preservative in modern formulations is phenoxyethanol, typically used at around one per cent. Parabens — methylparaben, propylparaben and their relatives — remain among the most thoroughly studied and effective preservatives available, despite widespread consumer concern that is not supported by regulatory toxicology assessments from the European Commission’s Scientific Committee on Consumer Safety.
Products labelled preservative-free are not unpreserved. They use alternative preservation strategies: multifunctional ingredients like caprylyl glycol or ethylhexylglycerin that have preservative properties without being classified as preservatives, or airless packaging that limits microbial contamination. These approaches can be effective, but they are not inherently safer or better than conventional preservation.
Fragrance: The Most Common Sensitiser
The word parfum or fragrance on an ingredient list represents a blend that can contain dozens of individual aroma chemicals, none of which need to be individually disclosed except for 26 allergens identified by the EU Cosmetics Regulation. Fragrance is the most common cause of allergic contact dermatitis from cosmetic products, according to a systematic review published in Contact Dermatitis in 2018.
If your skin is reactive, scanning for parfum is the single most useful thing you can do with an ingredient list. Its position — usually near or below the one-per-cent line — tells you the total fragrance concentration is modest, but even trace amounts can trigger sensitisation in predisposed individuals. Products labelled fragrance-free should contain no masking fragrances either, though this is not always the case.
Claims That the Label Cannot Support
No ingredient list can tell you whether a product works. It tells you what is in the jar, in what approximate order, and by implication what is not. It cannot tell you whether the active ingredient was stable at the time of manufacture, whether the formulation delivers it to the right layer of skin, or whether the clinical evidence supports the product’s marketing claims.
Reading labels is a necessary skill, but it is a starting point, not a conclusion. The ingredient list protects your right to know what you are putting on your skin. It does not replace the need for independent testing, published efficacy data, and the kind of critical evaluation that no amount of label reading can substitute for.