The 1% Line

What It Is

In most regulated markets — including the EU, UK, US, Canada, Japan and Australia — skincare brands must list ingredients in descending order of concentration, but only down to 1%. Any ingredient present at 1% or less may be listed in any order the brand chooses, typically grouped by category or arranged for marketing effect.

This single rule is the most useful tool a consumer has for judging whether a product actually contains meaningful amounts of its marketed actives.

How It Looks

Why It Matters — "Fairy Dusting"

Fairy dusting is the industry term for adding an active ingredient at too low a concentration to do what the packaging implies. A product called "Retinol Renewing Serum" that lists retinol after fragrance and preservatives is almost certainly fairy-dusted: retinol needs around 0.3–1% to deliver the clinical effects people buy retinol for. Below that, it's a marketing claim, not a treatment.

The 1% line is the single best lens for catching this. Once you learn to mentally draw it, product marketing becomes much harder to fall for.

How to Find the Line Yourself

Ingredients that nearly always sit at or below 1% are your anchor markers. The first one you spot in the list tells you roughly where the 1% line falls. Common markers, from most reliable to somewhat less so:

• Preservatives: phenoxyethanol, chlorphenesin, dehydroacetic acid, sodium benzoate, potassium sorbate, ethylhexylglycerin, caprylyl glycol
• Chelators: disodium EDTA, tetrasodium EDTA
• pH adjusters: sodium hydroxide, citric acid, triethanolamine
• Vitamin E (tocopherol / tocopheryl acetate) — in cosmetic use, almost always under 1%
• Fragrance allergens: limonene, linalool, geraniol, citronellol, eugenol (EU labelling threshold is 0.001–0.01%)

Skin Stacker's ingredient decoder draws the line automatically on every product it analyses — so you don't have to memorise the markers.

Important Caveats

The 1% line is a strong signal, not a certainty. A handful of scenarios break the pattern:

• Retinoids are often dosed intentionally low — 0.1% or even 0.025% retinol can be clinically effective in the right vehicle, especially in gentle starter products. Low does not always mean fairy-dusted.
• Some peptides work at very low percentages — Argireline at 5% is typical but meaningful effect has been shown below 1% in certain vehicles.
• Fragrance compounds can cross the 1% line in some products, though the individual declared allergens (limonene, linalool, etc.) are always well below.
• Listed in the wrong order on purpose: while the EU and FDA both require concentration order above 1%, enforcement is inconsistent and non-compliant brands exist. The 1% line assumes good-faith labelling.

For the clearest read, combine the 1% line with the stated percentage of hero actives (when brands disclose them) and the product's clinical claims. If a brand claims "10% niacinamide" and niacinamide is third on the list, that's consistent. If they claim "clinical retinol" and retinol sits below phenoxyethanol, the numbers can't match.

Related Reading

• INCI — the international cosmetic labelling system
• How to Read a Skincare Ingredient Label (blog)
• Fragrance in Skincare
• Retinol — effective concentrations
• Niacinamide — effective concentrations