What to avoid on the label, and what not to worry about

1. Fragrance and parfum, including essential oils. The highest-yield cut by a distance. Fragrance has no function in a foundation, and a thinned mature barrier is more permeable to it — so a product you wore for twenty years can start stinging without the formula having changed. Essential oils are fragrance: lavender, citrus and mint are among the more common irritants in cosmetics and appear frequently in products marketed as gentle.

2. Drying alcohols high in the list — alcohol denat., SD alcohol, isopropyl alcohol. They evaporate fast and take barrier lipids with them, which on skin already short of oil leaves a tight surface that shows texture. Note that these are different things from fatty alcohols, below.

3. Longwear film formers and the claims attached to them. Trimethylsiloxysilicate and similar film formers produce the hard, continuous, transfer-resistant film that longwear is sold on — and a hard film on a face that flexes cracks along the fold. This is a formula-design objection rather than an ingredient-safety one.

4. Heavy oil absorbers on dry skin — silica, kaolin and starches high in the list, which is what mattifying is made of. They absorb oil your skin may no longer be producing much of.

5. Physical exfoliants in anything, which is a routine point rather than a makeup one. On thin skin a grit scrub causes micro-damage that shows up as roughness and reactivity, which then shows through any base.

Silicones — dimethicone, cyclopentasiloxane, dimethicone crosspolymer. Among the least reactive ingredients in cosmetics, and the source of slip: the property that lets a foundation glide across a crease instead of sinking into it. They do not suffocate skin, they do not cause breakouts in most people, and avoiding them on mature skin costs you the single most useful mechanical property a base can have. The one real caution is layering order — silicone is hydrophobic, so a water-based product applied over it beads up and pills. See silicone versus water-based primer.

Mineral filters — zinc oxide and titanium dioxide. Low-reactivity sun filters that sit on the surface rather than absorbing, which is why they are frequently recommended for reactive skin. Their genuine drawback is cosmetic: a high load reads ashy on deep skin and can bounce camera flash.

Fatty alcohols — cetyl, stearyl, cetearyl alcohol. Emollients, and the opposite of drying alcohols despite sharing a word. They are part of what makes a cream feel like a cream, and cutting them from a dry-skin routine is a mistake.

Preservatives — phenoxyethanol, and the paraben family. Every water-containing cosmetic needs them, and an unpreserved product sitting warm in a bathroom is a genuine problem where a preserved one is not. A minority of people react to specific preservatives, which is a reason to change brand rather than to avoid preservation.

Humectants — glycerin, hyaluronic acid, sodium hyaluronate. Useful, cheap, and most effective with an emollient over them. Glycerin in particular is the quiet workhorse in almost everything that works.

The front of the box is frequently the better guide, because a claim describes the formula's design goal and a single ingredient does not.

'Longwear', '24-hour', 'transfer-proof' → a hard continuous film. It will crack along a crease.

'Full matte', 'shine control', 'oil-free' → oil absorbers and probably a drying alcohol. Papery on skin short of oil.

'Blurring', 'poreless', 'soft-focus' → silicone elastomers. Genuinely effective for a few hours on a textured area; not a filler.

'Hydrating', 'serum', 'skin tint' → more water and slip, less film-forming material. The right direction for mature skin.

'Clean', 'natural', 'free-from' → tells you nothing about performance and nothing reliable about gentleness. Plant extracts are a leading cause of cosmetic reactions, and a short synthetic ingredient list is frequently gentler than a long botanical one.

'Filling', 'erasing', 'reversing' lines → the budget went on the claim. Nothing in a foundation fills a crease.

'Dermatologist-tested' or 'dermatologist-approved' → a brand claim with no standardized meaning. Worth noting rather than relying on.

Ingredient lists are printed in some of the smallest type in retail, which makes this a genuinely difficult task rather than a tedious one.

Photograph the label and zoom in. A phone camera is the most practical magnifier available and the image can be enlarged as far as needed. It also lets you keep a record of a formula you got on with.

Look it up instead of reading it. Most manufacturers publish the full ingredient list on their own website, where it can be enlarged in a browser, and retailer product pages usually carry it too. That is far easier than reading a tube.

You only need the first five or six entries plus a search for one word: fragrance or parfum. That reduces the task from reading a paragraph to checking a handful of items.

Keep a short written list of what to avoid in large type, in your bag or on your phone, rather than trying to recall it in a shop.

And ask. Staff at a counter can read a list aloud, and that is a reasonable thing to ask for.