You've probably turned over a moisturiser or shampoo bottle and been confronted with a wall of Latin-sounding names. "Aqua, Glycerin, Cetearyl Alcohol, Dimethicone..." — what does any of it mean? And why don't they just write it in English?
Here's your complete guide to understanding cosmetic ingredient lists in the UK.
Why Are Cosmetic Ingredients Written in Latin?
Cosmetic ingredients use the INCI system — International Nomenclature of Cosmetic Ingredients. This standardised naming system was created so that the same ingredient has the same name regardless of what country you buy the product in. "AQUA" means water whether you're in London, Tokyo, or Sao Paulo.
Under EU and UK law (EU Cosmetics Regulation 1223/2009, retained in UK law), all cosmetic products must list their ingredients using INCI names on the packaging.
The Order Matters
Ingredients are listed in descending order of concentration. The first ingredient is present in the highest amount, and the last ingredient in the smallest amount.
There's an important exception: ingredients present at less than 1% concentration can be listed in any order after the 1% line. Unfortunately, that line isn't marked on the label — but with experience you can estimate it.
Rule of thumb: In most skincare products, the first 5-7 ingredients make up the vast majority of the formula. Everything after phenoxyethanol (a common preservative used at 1% or less) is likely below 1%.
Common INCI Names Decoded
The Base (first few ingredients)
- AQUA = Water. Almost always first in water-based products.
- GLYCERIN = Glycerine. A humectant that draws moisture to skin. One of the safest, most effective skincare ingredients.
- DIMETHICONE = A silicone that creates a smooth, protective feel. Not absorbed by skin.
- CETEARYL ALCOHOL / CETYL ALCOHOL = Fatty alcohols (not drying alcohols). They condition and thicken formulas.
The Active Ingredients
- NIACINAMIDE = Vitamin B3. Brightens, reduces pores, strengthens barrier. Very well evidenced.
- RETINOL = Vitamin A. Anti-ageing gold standard. Avoid during pregnancy.
- ASCORBIC ACID = Vitamin C. Antioxidant and brightener.
- HYALURONIC ACID = A hydrating molecule that holds 1000x its weight in water.
- SALICYLIC ACID = BHA. Exfoliates inside pores. Great for acne.
- TOCOPHEROL = Vitamin E. Antioxidant and skin conditioner.
The Preservatives
- PHENOXYETHANOL = A widely used preservative. Generally well tolerated.
- SODIUM BENZOATE / POTASSIUM SORBATE = Mild preservatives common in "clean" beauty.
- METHYLPARABEN / PROPYLPARABEN = Paraben preservatives. Effective but controversial — many clean beauty brands avoid them.
The Texture and Feel
- CARBOMER = Creates gel texture.
- XANTHAN GUM = Natural thickener from bacterial fermentation.
- SODIUM HYDROXIDE = Lye. Used in tiny amounts to adjust pH. Safe in finished products.
- CITRIC ACID = pH adjuster from citrus. Completely safe.
Plant Ingredients: The Latin Names
INCI requires plant ingredients to use their Latin botanical name followed by the plant part and preparation method:
- ALOE BARBADENSIS LEAF JUICE = Aloe vera
- BUTYROSPERMUM PARKII BUTTER = Shea butter
- COCOS NUCIFERA OIL = Coconut oil
- HELIANTHUS ANNUUS SEED OIL = Sunflower oil
- ARGANIA SPINOSA KERNEL OIL = Argan oil
- CAMELLIA SINENSIS LEAF EXTRACT = Green tea extract
- ROSA CANINA SEED OIL = Rosehip oil
This is why ingredient lists look so intimidating — perfectly ordinary plant oils get scientific names.
Colour Index (CI) Numbers
Colours in cosmetics use CI (Colour Index) numbers:
- CI 77891 = Titanium dioxide (white pigment)
- CI 77491 = Iron oxide red
- CI 77492 = Iron oxide yellow
- CI 77499 = Iron oxide black
These mineral pigments are safe. They're the coloured ingredients in foundations, eyeshadows, and blushes. "May contain" sections list all possible colours used across shade variants.
Red Flags to Watch For
When scanning an ingredient list, here are patterns that warrant closer inspection (see our full guide to ingredients to avoid in skincare):
- PARFUM / FRAGRANCE early in the list = high fragrance concentration. Greater sensitisation risk.
- Multiple parabens = the product uses paraben cocktails. Consider paraben-free alternatives.
- DMDM HYDANTOIN, QUATERNIUM-15 = formaldehyde releasers. Avoid if possible.
- ALCOHOL DENAT. in the first 5 ingredients = high alcohol content. Can be drying for skin.
The Easy Way: Use IngredScan
Rather than memorising INCI names, scan any cosmetic product with IngredScan. We automatically identify every ingredient, match it against our database of 100+ documented cosmetic ingredients, and flag anything of concern. Each ingredient gets a risk rating (low, medium, high) with an evidence-based explanation.
The goal isn't to make you afraid of your products — it's to give you the knowledge to make informed choices about what you put on your skin every day.