From hyaluronic acid to niacinamide and retinol, what the names on your serum actually mean, explained without jargon.

Quick look

1. Ingredient names on UK cosmetics follow standard INCI names, and the European Commission’s CosIng database lets you look any of them up.
2. Hyaluronic acid and glycerin pull water into the skin, while ceramides and niacinamide support the barrier that keeps moisture in.
3. Niacinamide suits nearly every skin type, and a stronger concentration is not automatically better than a modest one.
4. Salicylic acid and benzoyl peroxide are NHS-named options for acne, while prescription retinoids are stronger and need a GP.
5. Niacinamide and vitamin C work best at different pH levels, so many routines keep them at different times of day.

Turn over a serum and you meet a wall of chemistry: sodium hyaluronate, niacinamide, tocopherol. The names are standardised so the same ingredient reads the same way on every label, but nobody hands you a decoder. This glossary covers the names most likely to appear on British shelves, what each ingredient does and which skin types it tends to suit.

How to Read an Ingredient List in the UK

The names on cosmetic labels come from a shared glossary of common ingredient names, known as INCI names, drawn up for labelling cosmetic products. The European Commission keeps a public database called CosIng where you can look any name up. CosIng is for information only and has no legal force; the rules on which substances may be used in cosmetics, and in what conditions, sit in Regulation (EC) No 1223/2009.

Two things make the names easier to live with. One ingredient can travel under several labels: vitamin B3 appears as niacinamide or nicotinamide, and hyaluronic acid often shows up as sodium hyaluronate. And a long list does not mean a harsher product, because many entries are preservatives and emollients in small amounts. One label term worth knowing on sight is non-comedogenic, which describes products formulated not to clog pores; the NHS suggests choosing non-comedogenic skincare and makeup if you are prone to spots.

Humectants: The Water-Pullers

Hyaluronic acid. A sugar molecule your body makes naturally that acts as a powerful humectant, meaning it attracts and traps water. It can bind over a thousand times its weight in water, which is why it plumps the look of fine lines, and your natural supply declines with age, with loss starting from around 25. It suits nearly every skin type and is considered safe and unlikely to cause side effects when used on skin.

Sodium hyaluronate and hydrolyzed hyaluronic acid. Laboratory-made relatives of hyaluronic acid that work the same way. Formulas can use different molecular weights, which changes how each version behaves on the skin, so two hyaluronic products can feel completely different.

Glycerin. One of the most common humectants in skincare, it pulls water into the outer layers and holds it there. Cheap, well tolerated and found in everything from cleansers to rich creams, it suits even reactive skin.

Panthenol. A humectant that helps skin hold moisture while feeling soothing. A sensible pick for dry or tight-feeling skin.

Barrier Helpers

Ceramides. Fatty molecules that sit between skin cells and help form the barrier keeping water in and irritants out. Ceramide creams aim to top up what dry, sensitive or mature skin has less of, so they suit skin that feels rough, flaky or easily stung.

Niacinamide. Also called nicotinamide, this is a water-soluble form of vitamin B3 and one of the most researched skincare ingredients, with decades of safe use in cosmetics behind it. Studies link it to a stronger skin barrier, less moisture loss, calmer redness, a more even tone and balanced oil production, and it supports the skin’s natural ceramide content. It is a gentle, well-tolerated ingredient, so there is rarely a reason to chase the strongest formula on the shelf. It suits oily, spot-prone and sensitive skin alike and often appears in products aimed at making pores look smaller; if the subject interests you, read our piece on whether pores really open and close.

Squalane. A lightweight, oil-like ingredient that mimics squalene, a substance your skin makes naturally. It softens without feeling greasy, so it works for most skin types, including combination skin that dislikes heavy creams.

Exfoliating Acids

AHAs (alpha hydroxy acids). Water-loving acids that loosen the bonds holding dull, dead cells to the skin’s surface, leaving it smoother and brighter. They suit normal to dry or dull skin, but they can sting, so start low and build up slowly.

Glycolic acid. The smallest and quickest-working AHA, used for texture and tone. That small size also makes it the most likely to irritate, so sensitive skin is usually better off with lactic acid or a PHA.

Lactic acid. A larger, generally gentler AHA that also holds water like a humectant. A common starting point for skin that found glycolic acid too much.

Salicylic acid. An oil-soluble acid that can get inside pores rather than working only on the surface. The NHS names it as a spot treatment you can try for acne, and a pharmacist can advise on the options. It suits oily and blemish-prone skin, and it works best alongside gentle habits: the NHS recommends washing twice a day with a gentle cleanser and warns that scrubbing irritates skin and can make acne worse. If home remedies tempt you, read our verdict on toothpaste as a spot treatment first.

PHAs (poly hydroxy acids). Larger molecules than AHAs, so they work more slowly and sit more superficially. The gentlest of the exfoliating acids and a reasonable choice for easily flushed skin.

Vitamin C and Other Antioxidants

Ascorbic acid (vitamin C). An antioxidant that helps protect skin against free radicals and is used to brighten tone and fade the look of dark marks. It is fussy about formulation, so packaging and pH matter, and it can tingle on sensitive skin.

Tocopherol (vitamin E). An antioxidant often paired with vitamin C and usually included to soften and support the skin barrier. Well tolerated by most skin types.

Niacinamide has antioxidant properties too, one more reason it shows up in routines aimed at uneven tone and early signs of ageing.

Retinol, Retinoids and Peptides

Retinol. A vitamin A derivative used in non-prescription products to smooth texture, soften fine lines and even out tone. It can cause dryness and flaking at first, so start slowly and let your skin adjust before increasing how often you use it.

Tretinoin, adapalene and isotretinoin. Retinoid medicines for acne that are available on prescription, with a GP also able to refer you to a dermatologist. They are stronger than anything on a shop shelf and can be very effective for more severe acne, which is why a conversation with a doctor beats guesswork here.

Peptides. Short chains of amino acids used in creams aimed at firmness and fine lines. Gentle and easy to layer, so they suit sensitive skin and skincare beginners alike.

Soothing Ingredients, and What Fragrance-Free Really Means

Allantoin. A soothing agent that calms irritation and leaves skin feeling soft and comfortable. Often included alongside stronger actives to take the edge off them.

Centella asiatica (cica). A plant extract used in calming creams and serums for red, reactive skin. It is aimed at comfort rather than dramatic results, and suits sensitive types best.

Fragrance is where labels get slippery. Fragrance-free should mean no fragrance has been added, while a product described as unscented can still contain a masking fragrance to cover the smell of other ingredients. If scent bothers your skin, check for parfum on the ingredient list rather than trusting the front of the pack.

Which Ingredients Do Not Mix Well

Most ingredients get along better than the internet suggests, but timing matters for a few pairings. Niacinamide and vitamin C work best at different pH levels, so many routines keep them at different times of day, for example vitamin C in the morning and niacinamide later. Niacinamide is otherwise compatible with most non-prescription ingredients and is often used alongside retinol.

Stacking several exfoliating acids in one evening is a faster route to sore skin than better skin. Prescription retinoids also deserve their own space rather than a pile of actives on top. If a product irritates, stop using it and give your skin a simple, gentle routine until it settles.

Whatever the combination, sunscreen is the ingredient that makes the rest of the routine worth doing. A daily sunscreen with SPF 30 or higher is standard dermatologist advice. Our guide to whether you need SPF on cloudy days takes that question on in detail, and our breakdown of the real cost of a year of sunscreen shows it is cheaper than most people expect.

Little trick: Introduce one new product at a time and give it a few weeks before adding another. That way you can tell which ingredient is helping and which one is causing trouble.

Ask away

Can I use hyaluronic acid every day?

Yes. It is considered safe and unlikely to cause side effects when used on skin, and it suits almost every skin type, including sensitive skin.

What strength of niacinamide should I look for?

There is no need to chase the highest number on the label. Stronger is not automatically better, and a modest concentration can do the job alongside the rest of your routine.

Do I still need sunscreen if my moisturiser has good ingredients?

Yes. A daily sunscreen with SPF 30 or higher is standard dermatologist advice, and it protects the results your other ingredients are working towards.

How many new products should I add at once?

One. Give each new ingredient a few weeks before adding another so you can tell what is helping and what is irritating your skin.