Plain-language reference
What these skincare ingredients actually mean
A label can sound technical without being useful. This glossary explains what each recurring term is, what job it may perform, why formulators use it, and what the name alone cannot prove.
Lipids
In plain English: A broad family of oily or fat-like molecules. Many occur naturally in skin, including ceramides, cholesterol and fatty acids in its outer barrier.
What it does in skin: Skin uses lipids between its outer cells rather like mortar between bricks. Ceramides, cholesterol and fatty acids are important members of that mixture.
Why it is in products: Formulas use lipids to soften skin, reduce a dry or tight feel, and support the oily phase of an emulsion.
What not to assume: “Contains lipids” does not reveal their amount, ratio, delivery, or finished-product performance.
Back to top ↑Ceramides
In plain English: A family of waxy skin lipids—not one single ingredient.
What it does in skin: They are major components of the outer skin barrier and help organize the lipid layers that limit water loss.
Why it is in products: They are added to moisturizers, serums and ampoules to support a barrier-focused formula and improve skin conditioning.
What not to assume: A ceramide name on a label does not tell us the concentration or prove barrier repair.
Back to top ↑Ceramide NP
In plain English: One named ceramide class commonly used in cosmetics.
What it does in skin: The letters describe part of its chemical structure; NP is not a quality grade.
Why it is in products: It is used as a skin-conditioning lipid, often with lecithin, cholesterol or other ceramides.
What not to assume: NP is not automatically weaker or stronger than AP, EOP, NS or NG.
Back to top ↑Ceramide AP
In plain English: Another structurally defined ceramide class.
What it does in skin: It belongs to the same broad barrier-lipid family but has a different fatty-acid structure from Ceramide NP.
Why it is in products: Brands may combine it with other ceramide classes to create a broader disclosed lipid mixture.
What not to assume: More ceramide classes can improve formula transparency without proving better results.
Back to top ↑Ceramide EOP
In plain English: A ceramide class with a longer, ester-linked fatty-acid structure.
What it does in skin: Related long-chain ceramides contribute to the organization of skin’s outer lipid layers.
Why it is in products: It appears in some multi-ceramide complexes intended for barrier-focused skincare.
What not to assume: An INCI list cannot show whether it is present at a meaningful level or arranged like skin lipids.
Back to top ↑Ceramide NS
In plain English: A named non-hydroxylated ceramide class.
What it does in skin: It is one member of the larger ceramide family in the stratum corneum.
Why it is in products: It is usually included as part of a multi-lipid or multi-ceramide blend.
What not to assume: The letters identify structure, not clinical strength.
Back to top ↑Ceramide NG
In plain English: A ceramide class sometimes also encountered under older naming conventions.
What it does in skin: Its structure differs from other named ceramides while serving within the same broad lipid system.
Why it is in products: It can broaden the list of disclosed ceramide types in a formula.
What not to assume: Naming conventions and supplier blends can complicate direct label comparisons.
Back to top ↑Ceramide AS
In plain English: A hydroxylated ceramide class.
What it does in skin: It is one of several structurally distinct ceramides associated with the outer skin barrier.
Why it is in products: It normally appears within a blend rather than as a consumer-facing hero ingredient.
What not to assume: Its presence alone does not establish concentration or efficacy.
Back to top ↑Ceramide complex
In plain English: A supplier or brand blend whose exact ceramide composition may or may not be fully disclosed.
What it does in skin: Its relevance depends on which lipids it contains and how the finished product is formulated.
Why it is in products: Complexes make manufacturing easier and let brands combine ceramides with carriers or supporting lipids.
What not to assume: A branded-complex percentage is not necessarily the percentage of pure ceramides.
Back to top ↑Cholesterol
In plain English: A lipid naturally present in skin as well as elsewhere in the body.
What it does in skin: Alongside ceramides and fatty acids, it helps form the organized lipid matrix around outer skin cells.
Why it is in products: It is added to barrier-focused formulas as a supporting lipid, often beside ceramides.
What not to assume: Its presence is useful formula information, but the label does not reveal the lipid ratio.
Back to top ↑Fatty acids
In plain English: Building-block molecules found in oils, skin lipids and many emulsions.
What it does in skin: Free fatty acids are one of the major lipid groups in the outer skin barrier.
Why it is in products: They can condition skin, support texture, or form part of a ceramide/cholesterol/fatty-acid system.
What not to assume: Plant oils contain fatty components but are not interchangeable with a precisely designed free-fatty-acid mixture.
Back to top ↑Phytosphingosine
In plain English: A lipid-related molecule and structural part of some ceramides.
What it does in skin: It belongs to the family of sphingoid bases involved in skin-lipid biology.
Why it is in products: It may appear as a supporting skin-conditioning ingredient or alongside ceramides.
What not to assume: Its presence does not prove that the formula recreates the skin barrier.
Back to top ↑Sterols
In plain English: A family of ring-shaped lipids; cholesterol is one example.
What it does in skin: Different sterols can interact with lipid mixtures and contribute to skin conditioning.
Why it is in products: Plant sterols are often used as emollient or supporting lipid ingredients.
What not to assume: A plant sterol is not automatically equivalent to cholesterol in a studied formulation.
Back to top ↑Lecithin / hydrogenated lecithin
In plain English: A mixture rich in phospholipids that helps oil and water coexist.
What it does in skin: Phospholipids can condition skin and form delivery structures.
Why it is in products: Lecithin is commonly used as an emulsifier, stabilizer or carrier for lipid ingredients.
What not to assume: It supports formulation; it is not evidence that ceramides reach a particular skin layer.
Back to top ↑Humectants
In plain English: Ingredients that attract and hold water in the upper layers of skin.
What it does in skin: They can increase temporary hydration and reduce a dry, tight feel.
Why it is in products: Glycerin, hyaluronic acid, propanediol and betaine are common examples.
What not to assume: In dry conditions or dry skin, a humectant serum may still need an emollient or moisturizer over it.
Back to top ↑Glycerin
In plain English: A widely used humectant with strong general evidence for skin hydration.
What it does in skin: It helps the outer skin hold water and can improve softness.
Why it is in products: It is inexpensive, stable and compatible with many serum and moisturizer formulas.
What not to assume: Its familiar name does not make a product ordinary or ineffective; finished-formula design still matters.
Back to top ↑Hyaluronic acid / sodium hyaluronate
In plain English: A water-binding polymer; sodium hyaluronate is a common salt form.
What it does in skin: Topically it mainly supports surface hydration and a temporarily plumper feel.
Why it is in products: It is added to watery serums and ampoules as a humectant and texture ingredient.
What not to assume: Molecular weight, concentration and formula context matter; the name alone cannot predict results.
Back to top ↑Emollients
In plain English: Ingredients that smooth and soften the skin surface.
What it does in skin: They fill rough spaces between shedding skin cells and improve flexibility and feel.
Why it is in products: Squalane, triglycerides, esters and many oils are used to make formulas feel less dry.
What not to assume: Emollient does not mean pore-clogging; tolerance depends on the complete formula and the individual.
Back to top ↑Squalane
In plain English: A stable, lightweight emollient related to squalene found naturally in skin oils.
What it does in skin: It reduces roughness and improves slip and softness.
Why it is in products: It is used in oils, emulsions and milky serums because it is stable and usually feels lighter than many plant oils.
What not to assume: It conditions skin but is not one of the three principal barrier-lipid groups discussed in ceramide-ratio research.
Back to top ↑Occlusives
In plain English: Ingredients that form a surface film and slow water evaporation.
What it does in skin: They can be especially useful for very dry skin by reducing transepidermal water loss.
Why it is in products: Petrolatum is the classic example; waxes, silicones and richer oils can also contribute.
What not to assume: A watery ampoule is rarely a complete substitute for an occlusive moisturizer.
Back to top ↑Panthenol
In plain English: Pro-vitamin B5 used as a humectant and skin-conditioning ingredient.
What it does in skin: It can support hydration and a softer, more comfortable feel.
Why it is in products: It is common in soothing-positioned serums, ampoules and moisturizers.
What not to assume: Its presence does not make the finished product a medical treatment.
Back to top ↑Niacinamide
In plain English: A form of vitamin B3 used in many leave-on skincare products.
What it does in skin: Depending on concentration and formula, research supports roles in barrier function, uneven tone and oil regulation.
Why it is in products: It is popular because one well-formulated ingredient can address several cosmetic concerns.
What not to assume: The ingredient list often does not disclose concentration, and stronger is not always better tolerated.
Back to top ↑Peptides
In plain English: Short chains of amino acids.
What it does in skin: Different peptides have different proposed roles; the category name alone says very little.
Why it is in products: They are often included for conditioning or appearance-focused claims.
What not to assume: Identity, concentration, stability and finished-product evidence matter more than the word “peptide.”
Back to top ↑Fragrance / parfum
In plain English: A mixture added primarily to create or mask scent.
What it does in skin: It is not needed for hydration or barrier support and can bother some fragrance-sensitive users.
Why it is in products: Brands use it to shape the sensory experience or cover raw-material odors.
What not to assume: “Fragrance-free” and “unscented” are not always equivalent; aromatic plant extracts may also contribute scent.
Back to top ↑Alcohol denat.
In plain English: Ethanol made unsuitable for drinking.
What it does in skin: It evaporates quickly and can feel light or cooling; high exposure may feel drying or irritating to some people.
Why it is in products: It can dissolve ingredients, improve spread, reduce heaviness and help a formula dry faster.
What not to assume: Position and amount matter. Its presence is not automatically bad, but sensitive or very dry skin may prefer less.
Back to top ↑Snail secretion filtrate
In plain English: Filtered material collected from snail secretions.
What it does in skin: It is used for hydration and conditioning claims, but composition varies with sourcing and processing.
Why it is in products: It is common in K-beauty essences and serums for texture and marketing as well as skin conditioning.
What not to assume: It is animal-derived, so it is not vegan; a ppm claim still needs context about the complete formula.
Back to top ↑How to use this glossary
Treat ingredients as clues, not verdicts. The complete formula, ingredient amounts, delivery system, packaging, stability and your own skin all affect the result. Our methodology explains how we turn those clues into cautious product comparisons.