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by Ivy AI

Skincare Ingredient Dictionary: 50+ Ingredients A–Z

Search common skincare and cosmetic ingredients to understand what they do, how they may affect different skin types, and whether they carry a reported comedogenic or irritation risk. Browse individual ingredient guides below, or analyse a complete product label with the free ScanSkinAI Ingredient Checker.

Evidence-informed explanations · Comedogenic ratings · Irritancy guidance · Skin-type suitability

Popular Skincare Ingredients

The most-searched ingredient guides on ScanSkinAI.

Niacinamide

0

INCI: Vitamin B3

Antioxidants

A multi-tasking form of Vitamin B3 that reduces sebum, fades pigmentation, strengthens the moisture barrier and calms redness.

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Hyaluronic Acid

0

INCI: HA

Humectants

A powerhouse humectant that draws moisture from the air into the skin, holding up to 1,000 times its weight in water.

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Retinol

1

INCI: Vitamin A

Acids

A Vitamin A derivative that accelerates cell turnover, boosts collagen and is the gold-standard ingredient for reducing wrinkles and acne.

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Salicylic Acid

0

INCI: BHA

Acids

An oil-soluble exfoliant that penetrates into pores to dissolve sebum, dead skin and the plugs that cause blackheads and acne.

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Glycolic Acid

0

INCI: AHA

Acids

The smallest AHA molecule, derived from sugarcane. It exfoliates the surface of the skin to reveal smoother, brighter, more even-toned skin.

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Glycerin

0

INCI: Glycerol

Humectants

The most studied humectant in skincare. Draws water into the skin, supports barrier function and is suitable for every skin type.

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Ceramides

0

INCI: Ceramide NP

Emollients

Lipid molecules that make up roughly 50% of the skin's outer barrier. Topical ceramides replace what's lost through ageing, over-cleansing or inflammation.

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Tocopherol (Vitamin E)

2

INCI: Vitamin E

Antioxidants

A fat-soluble antioxidant that protects skin lipids from oxidative damage and stabilises formulations against rancidity.

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Squalane

1

INCI: Hydrogenated Squalene

Oils

A stable, saturated oil that mimics the skin's natural sebum. Modern squalane is derived from sugarcane or olives, not sharks.

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Azelaic Acid

0

INCI: Nonanedioic Acid

Acids

A naturally occurring acid that treats acne, rosacea and pigmentation simultaneously. The most pregnancy-safe active for acne treatment.

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Benzoyl Peroxide

0

INCI: BPO

Acids

An over-the-counter antibacterial that kills C. acnes bacteria and reduces inflammation. Often the first-line treatment for inflammatory acne.

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Centella Asiatica

0

INCI: Cica

Antioxidants

A botanical with proven anti-inflammatory, wound-healing and antioxidant properties. The hero of K-beauty 'Cica' creams.

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Browse Ingredients by Function

Each group below links to every matching ingredient in the directory.

Acne & blemish care

BHAs, AHAs and targeted actives for breakouts and congestion.

Hydration & humectants

Ingredients that draw and hold water in the skin.

Skin barrier support

Lipids and occlusives that reinforce the moisture barrier.

Exfoliating acids

AHAs and BHAs that loosen dead cells and smooth texture.

Antioxidants

Vitamins and polyphenols that help neutralise free radicals.

Emollients & oils

Softening agents that smooth and condition the skin surface.

Cleansing agents & surfactants

Detergents and mild cleansers that lift oil and dirt.

Preservatives

Compounds that keep formulas microbiologically safe.

UV filters

Ingredients that absorb or reflect UV radiation in sunscreens.

Thickeners & emulsifiers

Texturisers that give creams and lotions their structure.

Skincare Ingredients A–Z

C

C — 8 ingredients

2

Cetearyl Alcohol

INCI / also: Cetyl/Stearyl Alcohol Blend

A waxy, fatty alcohol blend that emulsifies oil and water and gives creams their thick, velvety texture. Despite the name, it does not dry skin.

Comedogenic 2/5Irritancy 1/5
4

Coconut Oil

INCI / also: Cocos Nucifera Oil

A rich, semi-solid plant oil high in saturated fats. Effective on the body and hair but notorious for clogging facial pores.

Comedogenic 4/5Irritancy 1/5
1

Capric Triglyceride

INCI / also: Caprylic/Capric Triglyceride, Fractionated Coconut Oil

A lightweight, refined fraction of coconut and palm fatty acids. Despite its origin, it is far less comedogenic than whole coconut oil.

Comedogenic 1/5Irritancy 0/5
2

Cetyl Alcohol

INCI / also: Hexadecan-1-ol

A fatty alcohol used as an emulsifier and emollient. Provides a soft, smooth feel to creams and lotions.

Comedogenic 2/5Irritancy 1/5
0

Ceramides

INCI / also: Ceramide NP, Ceramide AP, Ceramide EOP

Lipid molecules that make up roughly 50% of the skin's outer barrier. Topical ceramides replace what's lost through ageing, over-cleansing or inflammation.

Comedogenic 0/5Irritancy 0/5
0

Centella Asiatica

INCI / also: Cica, Gotu Kola, Tiger Grass

A botanical with proven anti-inflammatory, wound-healing and antioxidant properties. The hero of K-beauty 'Cica' creams.

Comedogenic 0/5Irritancy 0/5
0

Cocamidopropyl Betaine

INCI / also: CAPB

An amphoteric surfactant derived from coconut. Used as a milder co-surfactant to soften the harshness of stronger cleansing agents.

Comedogenic 0/5Irritancy 2/5
1

Castor Oil

INCI / also: Ricinus Communis Oil

A thick, viscous oil rich in ricinoleic acid. Used as an emollient, conditioner and the base of oil cleansing methods.

Comedogenic 1/5Irritancy 1/5
S

S — 8 ingredients

0

Salicylic Acid

INCI / also: BHA, Beta Hydroxy Acid

An oil-soluble exfoliant that penetrates into pores to dissolve sebum, dead skin and the plugs that cause blackheads and acne.

Comedogenic 0/5Irritancy 2/5
1

Squalane

INCI / also: Hydrogenated Squalene

A stable, saturated oil that mimics the skin's natural sebum. Modern squalane is derived from sugarcane or olives, not sharks.

Comedogenic 1/5Irritancy 0/5
2

Shea Butter

INCI / also: Butyrospermum Parkii

A rich, vitamin-packed plant butter from the African shea tree. Deeply emollient and softening, it's a classic ingredient for dry, mature and sensitive skin.

Comedogenic 2/5Irritancy 1/5
3

Stearic Acid

INCI / also: Octadecanoic Acid

A saturated fatty acid that thickens and stabilises creams. Naturally present in shea butter and cocoa butter.

Comedogenic 3/5Irritancy 1/5
0

Sodium Hyaluronate

INCI / also: Sodium Salt of Hyaluronic Acid

The salt form of hyaluronic acid. Smaller, more stable and faster to penetrate the upper layers of the skin.

Comedogenic 0/5Irritancy 0/5
5

Sodium Lauryl Sulfate

INCI / also: SLS

A harsh anionic surfactant that produces dramatic foam. Strips the skin barrier and worsens conditions like eczema and rosacea.

Comedogenic 5/5Irritancy 5/5
3

Sodium Laureth Sulfate

INCI / also: SLES

An ethoxylated surfactant — milder than SLS but still potentially drying. Common in shampoos and body washes.

Comedogenic 3/5Irritancy 3/5
0

Sulfur

INCI / also: Precipitated Sulfur

A keratolytic and antimicrobial. One of the oldest acne treatments still in use, particularly effective for inflammatory acne and rosacea.

Comedogenic 0/5Irritancy 3/5

How to Use This Skincare Ingredient Dictionary

  • Look up one ingredient. Use the search bar or the A–Z directory to read what an ingredient does, how it tends to behave on different skin types and any common cautions.
  • Analyse a whole product. A single ingredient rarely decides how a finished formula will perform. Paste the full INCI list into the Cosmetic Ingredient Checker to read the formula in context.
  • Consider concentration and order. Ingredients near the top of an INCI list are usually present at higher concentrations and have a bigger impact on the formula than those near the bottom.
  • Factor in your own skin. Skin sensitivity, climate, the rest of your routine and how a product is used all influence the result. Use ratings as one input alongside how your skin actually responds.

How Comedogenic Ratings Work

The comedogenic scale normally runs from 0 to 5. It originated in screening models — primarily the Fulton/Kligman rabbit-ear assay — that test how an ingredient behaves at a fixed, often high concentration on a sensitive surrogate tissue. The result is a useful reference, not a clinical prediction for any individual person or product.

Higher ratings indicate a greater reported pore-clogging potential, but the finished formulation, concentration and individual response still matter. An ingredient rated 4/5 in a screening model can sit well below the level that troubles real skin when used at a modest concentration inside a well-designed formula; equally, a low-rated ingredient can still feel heavy on someone whose skin tends to congest.

Use a rating to set expectations and to flag ingredients that deserve a closer look, not as a yes/no verdict. Patch testing on a small area, introducing one new product at a time, and tracking how your skin actually behaves over 4–6 weeks remain the most reliable tools available to a consumer.

How to Read an INCI Ingredient List

INCI stands for the International Nomenclature of Cosmetic Ingredients — the standardised naming system used on cosmetic labels worldwide. It is why a label may read Tocopherol rather than “vitamin E”, or Butyrospermum Parkii Butterrather than “shea butter”. The two refer to the same material; only the naming convention differs.

Ingredients above approximately 1% of the formula are listed in descending order of concentration. Ingredients below roughly 1% may appear in any order — this is why a single active named near the end of a list is rarely doing the heavy lifting that marketing copy implies.

Because a whole formula cannot be judged from one ingredient alone, the most useful workflow is to read the INCI list as a system: look at what dominates the first few lines, identify which actives appear and roughly where, and check anything you have a known sensitivity to.

Check a complete product

Paste your moisturiser, sunscreen or serum ingredient list into the free Cosmetic Ingredient Checker and get an instant per-ingredient breakdown of comedogenic and irritancy ratings, plus a summary of the formula as a whole.

Frequently Asked Questions

What does comedogenic mean?
Comedogenic describes an ingredient with a reported tendency to clog pores and contribute to comedones (blackheads and whiteheads). The widely used 0–5 scale comes from work by Dr James Fulton and Dr Albert Kligman in the 1970s using a rabbit-ear model. A rating is a useful screening reference for acne-prone skin, but it does not guarantee how a finished product will behave on a given person.
What does the 0–5 comedogenic scale mean?
0 indicates no reported pore-clogging in the original screening models (for example hyaluronic acid or glycerin). 1–2 is generally considered low risk. 3 is moderate. 4–5 indicates a higher reported risk. Higher numbers do not automatically mean a product will cause acne — concentration, the rest of the formula and your individual skin still matter.
Which ingredients are most often flagged for acne-prone skin?
Ingredients frequently flagged in screening data include isopropyl myristate, myristyl myristate, coconut oil, cocoa butter, lanolin and some lanolin derivatives, and high concentrations of oleic acid. These often appear in moisturisers, sunscreens, lip products and hair conditioners. Patch testing and an honest read of your own pattern remain useful alongside any rating list.
Are natural ingredients always non-comedogenic?
No. Many ingredients commonly described as natural carry higher comedogenic ratings — coconut oil and cocoa butter are common examples. Conversely, some synthetic ingredients such as dimethicone and mineral oil have very low reported pore-clogging potential. The word 'natural' on a label does not predict comedogenicity.
How do I check whether my moisturiser might clog pores?
Paste the complete ingredient list into the free ScanSkinAI Cosmetic Ingredient Checker at /cosmetic-ingredient-checker. It flags each ingredient with its reported comedogenic and irritancy ratings and summarises overall risk, so you can read a finished formula in context rather than judging it from a single ingredient.
What is INCI?
INCI (International Nomenclature of Cosmetic Ingredients) is the standardised naming system that appears on cosmetic labels worldwide. INCI names are usually scientific (for example Tocopherol, Niacinamide, Butyrospermum Parkii Butter) rather than the marketing names used in product copy.
Why does ingredient order matter on a label?
Ingredients above approximately 1% are listed in descending order of concentration, so the first few entries usually dominate the formula. Ingredients below roughly 1% may appear in any order, which is why a single low-concentration entry near the end of a list rarely tells you the whole story about how a product will perform.
Is a comedogenic rating the same as 'will cause acne'?
No. A rating is a screening reference, not a clinical prediction for any individual. Real-world acne risk depends on the finished product, how it is used, other products layered with it, your skin biology and many lifestyle factors. Use ratings as one input alongside how your skin actually responds.

Sources and Methodology

Entries in this dictionary draw on the regulatory and scientific reference sources most commonly used by cosmetic formulators and dermatology researchers. Ingredient functions, INCI names and safety information are cross-checked against:

  • European Commission CosIng — the EU database of cosmetic ingredients and their declared functions.
  • COSMILE Europe — the European cosmetics industry's consumer ingredient encyclopaedia.
  • Cosmetic Ingredient Review (CIR) — safety assessments published in the International Journal of Toxicology.
  • Peer-reviewed dermatology and cosmetic-science literature, including the original Fulton/Kligman comedogenicity work and follow-up studies.
  • Relevant government and regulatory sources such as the US FDA and the UK MHRA cosmetics guidance.

Content is written and maintained by the ScanSkinAI editorial and research team. Information here is intended for general education and is not a substitute for personalised advice from a qualified healthcare professional.

Last reviewed: 17 June 2026