Parfum
A blend of scent chemicals the brand doesn't have to itemise. Fragrance is the most common cause of allergic reactions to cosmetics — skip it if your skin is sensitive.
Fragrance allergen
Label guide
How to read the back of the bottle.
Five minutes, and you’ll never look at a label the same way: what the order means, how plant names work, where fragrance hides, what the little symbols say — and which claims to take with a pinch of salt.
The order
The first few ingredients are most of the product.
Ingredients are listed from most to least, down to about 1%. Below that line they can come in any order, and colours can be gathered at the very end. So the start of a list tells you what a product really is; the end tells you less.
Water first usually means a fluid, water-based product. Oils and butters near the top mean a richer one.
- Aquamost of it
- Glycerina lot
- Caprylic/Capric Triglyceridea fair bit
- Cetearyl Alcoholsome
about 1%
- Parfumany order from here
- Phenoxyethanol
- Niacinamide
- CI 77891colours: often last
The names
Plant names are Latin, with a clue in brackets.
Labels use one international vocabulary, INCI. Plants are written as genus and species, then the everyday name in brackets, then the part of the plant and what was made from it. The last two words tell you the most: a seed or fruit oil is pressed and gentle; a flower, leaf or peel oil is usually an essential oil, there for scent.
Camelliagenus
Oleiferaspecies
(Camellia)what you’d call it
Seedthe part
Oilwhat it is
Compare: Citrus Aurantium Amara (Neroli) Flower Oil — a flower oil, so an essential oil.
Fragrance
A secret recipe, with the allergens named.
“Parfum” or “fragrance” can stand for dozens of scent molecules — the recipe is a trade secret. What the label must name are the fragrance allergens, once there’s more than a trace: over 0.001% in products you leave on, 0.01% in ones you rinse off. In 2023 the EU widened that list from 26 allergens to more than 80, to reach labels by 2026–2028.
Essential oils count too: they’re natural sources of the same allergens, which is why labels mark them with a “+ occurs naturally in essential oils”.
Linalool
A floral scent molecule from lavender and many other plants. Becomes a stronger allergen once exposed to air.
Fragrance allergen
Limonene
A citrus scent molecule. Oxidises in air into compounds that commonly cause contact allergy.
Fragrance allergen
The symbols
What the little marks on the pack mean.
Open jar, “12M”
Use within 12 months of opening. Shown on products that keep for longer than 30 months.
Hourglass, with a date
Best before the end of that date. Used instead of the open jar when a product keeps for 30 months or less.
The amount, and a small “℮”
Anything over 5 ml or 5 g must say how much it holds — in ml or g, often with fl oz, the US measure. The ℮ beside it means an average fill, checked under EU packaging rules.
Stars and pluses
Footnotes. Look under the list: “* organic”, “+ occurs naturally in essential oils”. Peruse reads them for you.
“May contain”
Colours used in some shades of a range only. Your shade has some of them, not all.
CI numbers
Colour Index numbers: pigments and dyes, named the same way worldwide.
“(nano)” after a name
The ingredient is used as nanoparticles — often a mineral sunscreen filter. EU labels have to say so.
A flame
Flammable — on aerosols, which hold propellant gas. Keep away from heat.
Triman — a figure with arrows
On products sold in France: the pack can be sorted for recycling, with the sorting instructions beside it. Required there since 2015.
The Green Dot
Two arrows in a circle: the maker paid into a scheme that collects packaging. It doesn’t mean the pack is recyclable, or made of recycled material.
The claims
Words on the front, decoded.
- “Dermatologically tested”
A dermatologist oversaw a skin test — it doesn’t mean nobody will react.
- “Hypoallergenic”
Not a regulated term: the maker aimed to limit allergens, not that none are present.
- “Non-comedogenic”
The maker says it won’t clog pores; there’s no single standard test behind the word.
- “Free from…”
Tells you what isn’t in it — check what does the job instead (another preservative, another cleanser).
- “Clinically tested”
Means some testing was done, usually by the brand; the label doesn’t say how, or how many people.
- “Natural”
There’s no legal definition of natural for cosmetics — and natural ingredients can irritate too (essential oils often do).
Worth looking out for
A short list to know by name.
Some ingredients come up again and again in regulators’ reviews: preservatives that release formaldehyde, a few that commonly cause allergy, silicones that persist in the environment, and antioxidants and antibacterials under study for hormone effects. Here’s what Peruse says about each — and why.
The strictest line is “CMR”: substances that can cause cancer, damage DNA or harm fertility. The EU bans them from cosmetics, except the few its scientists have assessed and allowed at levels found safe.
A synthetic antioxidant listed as a possible carcinogen and under EU review as a possible endocrine disruptor.
Hormone concern
A synthetic antioxidant used in tiny amounts to keep oils fresh. Often listed next to BHA as a possible hormone disruptor; EU safety scientists reviewed it and allow it with strict limits.
Hormone concern
An antibacterial restricted in the EU and removed from US antibacterial soaps, over hormone effects, antibiotic resistance and environmental harm.
Hormone concernEnvironmental concern
D4, a volatile silicone. Classed in the EU as possibly harmful to fertility and as persisting in the environment, so it's restricted in wash-off products since 2020 and in leave-on products from 2026.
Hormone concernEnvironmental concern
D5, the most common volatile silicone — it gives a silky feel, then evaporates. Fine on skin, but it builds up in the environment, so the EU restricts it in wash-off products (since 2020) and in leave-on products (from 2026).
Environmental concern
A mix of volatile silicones — mostly D5, sometimes D4 and D6. Silky on skin, but all three build up in the environment, and the EU restricts them.
Environmental concern
DEA. Adjusts pH and helps foaming, but it can react with other ingredients to form nitrosamines, some of which cause cancer — so EU rules strictly limit it.
A foam booster made from coconut fatty acids and diethanolamine. It can carry traces of DEA, and it's listed as possibly carcinogenic (IARC group 2B). Common in shampoos.
Can irritate
A preservative that works by slowly releasing formaldehyde, a known sensitizer and carcinogen. Products containing releasers must carry a warning in the EU when formaldehyde levels are high.
Releases formaldehydeSensitizer
A formaldehyde-releasing preservative, banned in cosmetics in the EU.
Releases formaldehydeSensitizer
A formaldehyde-releasing preservative and a known cause of contact allergy.
Releases formaldehydeSensitizer
A formaldehyde-releasing preservative and a known cause of contact allergy.
Releases formaldehydeSensitizer
A preservative behind an epidemic of contact allergy in the 2010s. Banned in leave-on products in the EU; allowed only at low levels in rinse-off.
Sensitizer
Easier with a phone
Peruse does all of this for you: photograph the list, and it reads every ingredient, footnote and claim.
Scan a label