The Ingredient Codex
A–Z: Helpers, irritants, and hidden labels decoded — what's really in your skincare.
76 ingredients
Allantoin
A soothing agent derived from the comfrey plant that calms irritation and accelerates skin cell renewal. Found in many healing creams and sensitivity formulas.
Alpha-Arbutin
A stable, gentle brightening agent derived from bearberry that inhibits melanin production without the irritation of hydroquinone.
Azelaic Acid
A multitasking acid naturally occurring in grains that treats acne, rosacea, and hyperpigmentation with remarkable gentleness.
Bakuchiol
A plant-based alternative to retinol derived from the babchi plant. Provides similar anti-aging benefits with far less irritation — safe in pregnancy.
Benzoyl Peroxide
A powerful antimicrobial agent that kills acne-causing bacteria. Highly effective but one of the most drying and irritating acne ingredients.
BHT / Butylated Hydroxyanisole
Synthetic antioxidant preservative added to prevent rancidity. Not to be confused with BHA (Salicylic Acid) — they share initials but are entirely different chemicals.
Ceramide NP / AP / EOP
Natural lipid molecules forming 50% of the skin barrier. Topical ceramides replenish and reinforce the barrier to prevent moisture loss.
Centella Asiatica Extract
Also known as 'Cica' or Tiger Grass — a botanical powerhouse with wound-healing, anti-inflammatory, and barrier-restoring properties.
Carbomer / Carbopol
A polymer thickener that gives gels and serums their characteristic smooth texture. Present in countless formulas but rarely discussed.
Copper Tripeptide-1 (GHK-Cu)
A naturally occurring peptide complex that promotes wound healing, stimulates collagen and elastin, and has antioxidant properties.
Alcohol Denat. / SD Alcohol
A solvent and astringent added to products for quick-dry texture. One of the most common skin-barrier disruptors in skincare.
sh-Oligopeptide-1 / EGF
A signaling protein that triggers skin cell renewal and repair. Gaining popularity in K-beauty and advanced anti-aging formulations for its regenerative properties.
Lavandula Angustifolia / Citrus Aurantium etc.
Highly concentrated plant extracts marketed as 'natural.' In skincare, they are among the most common causes of allergic contact reactions.
Ferulic Acid
A plant-based antioxidant that dramatically amplifies the effectiveness of Vitamins C and E — the ultimate antioxidant team player.
Fragrance / Parfum
A catch-all listing hiding hundreds of undisclosed chemicals under one word. The #1 cause of contact dermatitis in skincare.
DMDM Hydantoin / Quaternium-15 / Imidazolidinyl Urea
Preservatives that slowly release formaldehyde — one of the most recognized skin sensitizers and a known carcinogen.
Glycerin / Glycerol
One of the most effective and safe humectants in skincare. Found in almost every moisturizer — draws water from the environment and deeper skin layers.
Glycolic Acid (AHA)
The smallest AHA molecule — exfoliates at the surface to reveal brighter, smoother skin and stimulates collagen over time.
Camellia Sinensis Leaf Extract
Rich in EGCG (epigallocatechin gallate) — a potent antioxidant that fights UV damage, reduces inflammation, and has mild sebum-regulating properties.
4-Hexylresorcinol
A potent brightening ingredient clinically shown to outperform kojic acid at reducing hyperpigmentation. Also has antioxidant and antimicrobial properties.
Sodium Hyaluronate
A naturally occurring molecule in the skin that holds up to 1000x its weight in water — the gold standard hydration ingredient.
Idebenone
A synthetic analog of CoQ10 — one of the most powerful antioxidants in skincare, rated higher than Vitamin C, E, and alpha lipoic acid in Environmental Protection Factor (EPF) tests.
Simmondsia Chinensis Seed Oil
Technically a liquid wax that closely mimics the skin's own sebum. One of the most balanced facial oils — moisturizes without clogging pores.
Kojic Acid
A naturally derived brightener from fungi used in food fermentation. Inhibits tyrosinase to reduce melanin production — popular in Japanese skincare traditions.
Kaolin
The gentlest cosmetic clay — absorbs excess oil and gently draws out impurities without over-drying like stronger clays (bentonite).
Lactic Acid (AHA)
A larger-molecule AHA that exfoliates more gently than glycolic acid while also acting as a humectant — the gentlest entry-point acid for beginners.
Glycyrrhiza Glabra Root Extract
A botanical brightener that inhibits tyrosinase (the enzyme responsible for melanin production) while also soothing inflammation.
Mandelic Acid (AHA)
The largest AHA molecule — derived from bitter almonds. Exfoliates even more slowly than lactic acid, making it the ideal acid for acne-prone and hyperpigmented darker skin tones.
Methylisothiazolinone / CMIT
A powerful preservative banned from leave-on EU products but still permitted in rinse-off products and common in US formulations.
Paraffinum Liquidum
Petroleum-derived occlusive that seals in moisture. Cosmetic-grade is generally safe, but heavy industrial grades in low-quality products can clog pores.
Citrus Aurantium Amara Flower Oil
A refined citrus blossom extract used at cosmetic concentrations for its calming and antioxidant properties. Unlike raw essential oil versions, formulated neroli at safe levels has a gentler profile.
Niacinamide (Vitamin B3)
A versatile Vitamin B3 that simultaneously minimizes pores, regulates oil, brightens skin tone, and strengthens the moisture barrier.
Avena Sativa Kernel Extract
Colloidal oat extract is FDA-approved to treat eczema and skin irritation. Rich in beta-glucan and avenanthramides — powerful anti-inflammatory compounds.
Benzophenone-3 / Oxybenzone
A chemical UV filter found in many sunscreens — highly effective at UV protection but controversial for systemic absorption and environmental impact.
D-Panthenol (Provitamin B5)
A provitamin B5 that penetrates deep into skin to act as both a humectant and skin-repairing agent, leaving skin soft and resilient.
PEG-100 Stearate / PEG-40 / Polyethylene Glycol
Polyethylene glycols are penetration enhancers that improve product texture. They can enhance absorption of other ingredients — including potentially harmful ones.
Palmitoyl Tripeptide-1 / Matrixyl
Short chains of amino acids that signal skin to produce more collagen and elastin — a gentler alternative or complement to retinol.
Phenoxyethanol
One of the most common preservatives in 'clean beauty' products — marketed as safer than parabens, but with its own contested safety profile.
Quercetin
A powerful flavonoid antioxidant found in plants that has anti-inflammatory, anti-aging, and UV-protective properties in topical application.
Rosa Canina Seed Oil
A cold-pressed botanical oil rich in linoleic acid (omega-6), beta-carotene, and Vitamin C precursors — historically used for scar healing and skin regeneration.
Resveratrol
A polyphenol antioxidant found in grapes and red wine that fights free radical damage, inflammation, and supports collagen production.
Retinol / Retinyl Palmitate
A Vitamin A derivative that accelerates cell turnover to smooth wrinkles, even tone, and reduce acne — the gold standard anti-aging ingredient.
Salicylic Acid (BHA)
A beta-hydroxy acid (BHA) that penetrates deep into pores to dissolve excess sebum and dead cells — the definitive acne-fighting exfoliant.
Dimethicone / Cyclopentasiloxane
A large family of silicone-based polymers giving products a silky, blurring feel — often listed under many different '-cone' names.
Sodium Lauryl Sulfate (SLS)
An aggressive surfactant that creates rich lather but strips the skin's natural lipid barrier, causing dryness and irritation with regular use.
Squalane
A lightweight, non-comedogenic oil derived from olives or sugarcane that mimics the skin's own sebum for seamless moisture locking.
CI 19140 / FD&C Red No. 40 / D&C Colors
Artificial colorants added purely for aesthetics — zero skin benefit and a commonly overlooked sensitizer.
Melaleuca Alternifolia Leaf Oil
A natural antimicrobial oil popular for acne — but classified as an irritant due to its potential to cause contact sensitization, especially in undiluted form.
Tocopheryl Acetate
The synthetic ester form of Vitamin E — commonly marketed as 'Vitamin E' but less bioavailable than pure Tocopherol, requiring skin enzyme conversion.
Tranexamic Acid
A newer brightening agent originally used in medicine that suppresses melanin synthesis through a unique pathway — gentle even for sensitive skin.
Urea
A naturally occurring component of the skin's Natural Moisturizing Factor (NMF). At low concentrations it hydrates; at higher it gently exfoliates.
L-Ascorbic Acid
The most potent antioxidant in skincare — protects against UV damage, inhibits melanin, and is essential for collagen synthesis.
Tocopherol
A fat-soluble antioxidant that protects cell membranes from oxidative damage. Works best in combination with Vitamin C and Ferulic Acid.
Salix Alba Bark Extract
A natural source of salicin — a compound related to salicylic acid — giving this botanical extract gentle exfoliating and anti-inflammatory properties.
Hamamelis Virginiana Leaf Extract
A botanical astringent widely marketed for acne and pores — but most commercial witch hazel is formulated with alcohol and can be drying and irritating.
Xanthan Gum
A natural polysaccharide used as a thickener and stabilizer in skincare products. Often found in gel-texture formulas.
Ilex Paraguariensis Leaf Extract
A South American botanical rich in polyphenols, xanthines, and chlorogenic acids — emerging in skincare for its antioxidant and energizing properties.
Zinc Oxide
The gold standard mineral sunscreen ingredient that physically reflects UV rays. Also has anti-inflammatory and mild antimicrobial properties — excellent for acne-prone and sensitive skin.
Zinc PCA
A zinc salt of pyrrolidone carboxylic acid — a natural component of the skin's NMF (Natural Moisturizing Factor) that regulates sebum and has antimicrobial properties.
Aloe Barbadensis Leaf Juice
A centuries-old healing plant rich in vitamins, enzymes, and amino acids. Soothes burns, hydrates, and accelerates wound healing.
Argania Spinosa Kernel Oil
Cold-pressed Moroccan oil rich in Vitamin E, fatty acids, and antioxidants. A North African beauty staple for centuries.
Adenosine
A naturally occurring molecule that soothes skin and supports collagen production — widely used in Korean anti-aging formulations.
Bisabolol / Alpha-Bisabolol
A chamomile-derived compound that calms irritation, reduces redness, and helps other actives penetrate deeper.
Caffeine
A vasoconstrictor and antioxidant that de-puffs, brightens dark circles, and protects against UV-induced oxidative damage.
Hydrolyzed Collagen / Soluble Collagen
The most abundant protein in skin. Topical collagen molecules are too large to penetrate deeply but provide surface hydration and film-forming benefits.
Dimethicone
A silicone-based occlusive that creates a smooth, protective film on the skin. Widely used for its silky texture and barrier-protecting properties.
Decyl Glucoside
A gentle, plant-derived surfactant from coconut and glucose. One of the mildest cleansing agents available — used in baby and sensitive-skin products.
Iron Oxides (CI 77489 / 77491 / 77492 / 77499)
Naturally mined mineral pigments that provide visible light protection — especially important for melasma and hyperpigmentation management.
Isododecane
A volatile hydrocarbon solvent that gives products a lightweight, fast-drying feel. Evaporates quickly without leaving residue.
Polygonum Cuspidatum Root Extract
A rich natural source of resveratrol — this plant extract provides potent antioxidant and anti-inflammatory benefits in skincare.
Madecassoside
One of the most active compounds from Centella Asiatica — clinically studied for its remarkable wound-healing and barrier-repair properties.
Chenopodium Quinoa Seed Extract
A nutrient-dense botanical extract rich in amino acids, vitamins, and minerals that nourishes and protects the skin barrier.
Tremella Fuciformis Sporocarp Extract
A natural alternative to hyaluronic acid — holds up to 500x its weight in water. Smaller molecules penetrate deeper for superior hydration.
Ubiquinone / Coenzyme Q10
A naturally occurring antioxidant that declines with age. Topical application helps neutralize free radicals and supports cellular energy production.
Xylitol
A sugar alcohol used as a natural humectant and prebiotic in skincare. Draws moisture to the skin while supporting a healthy microbiome.
Citrus Junos Fruit Extract
A Korean citrus fruit richer in Vitamin C than lemons. Provides brightening and antioxidant benefits with less irritation than pure ascorbic acid.
