Ingredient guide

A naturally occurring copper-binding tripeptide widely used in topical formulas and studied for its role in the appearance of skin firmness and texture.

A pair of palmitoyl "matrikine" messenger peptides formulated together. It is the current-generation successor to the original single-peptide Matrixyl, studied for the appearance of fine lines.

A peptide marketed as a topical option studied for the appearance of expression lines, sometimes called a "topical alternative" in marketing copy.

The most-studied form of topical vitamin C, an antioxidant associated with the appearance of brightness and evenness. It is also notoriously unstable, so packaging and pH matter.

A complex of signaling proteins secreted by cultured human skin cells, the hero of prestige "growth-factor" serums, studied for the appearance of firmness and fine lines.

A synthetic tripeptide included in some prestige serums and studied, in early research, for its association with the appearance of firmness.

A palmitoylated conditioning peptide commonly paired with Matrixyl in multi-peptide serums, studied for the appearance of smoother, firmer skin.

The best-studied over-the-counter vitamin A derivative and the reference cosmetic retinoid, associated with the appearance of fine lines and a smoother, more even-looking surface. It is notoriously unstable in air and light.

Retinol wrapped in a protective carrier (liposomes, silica or polymer shells) so it stays stable longer and releases gradually, which research links to comparable appearance benefits with less of the visible irritation.

A stable, water-soluble form of vitamin B3 and one of the more reliable multitaskers on a label, studied for the appearance of an even tone, refined-looking pores and a supported-looking barrier.

The zinc salt of a natural moisturising-factor amino acid, usually a supporting act to niacinamide, included for the look of a balanced, less-shiny complexion.

A lipophilic antioxidant and the classic partner to vitamin C. The two are studied together, each helping the other last, and it is flagged for antioxidant support and the appearance of conditioned skin.

A plant-derived antioxidant best known as the stabiliser in "CE ferulic" serums. It props up vitamins C and E and adds its own antioxidant support, usually dosed below 1% by design.

A humectant that holds many times its weight in water, used at a range of molecular sizes for the appearance of plumper, more hydrated-looking skin. It is a comfort and finish ingredient, not an anti-aging active.

A dicarboxylic acid found in grains, used in cosmetic-strength formulas for the appearance of a clearer, more even-looking complexion; the higher-strength versions are prescription drugs rather than cosmetics.

A plant compound marketed as a gentler "retinol alternative" for the appearance of fine lines. It is more shelf-stable than retinol, though its evidence base is far younger and thinner.

A stabilised, plant-derived brightening ingredient studied for the appearance of a more even tone and the look of reduced dark spots, typically used around 1–2%.

An oil-soluble, more shelf-stable vitamin C ester used as a gentler alternative to L-ascorbic acid, flagged for antioxidant support and the appearance of brightness, though derivatives carry thinner evidence than pure vitamin C.

A copper-free palmitoyl "matrikine" messenger peptide, often stacked with Matrixyl 3000, studied for the appearance of smoother, firmer-looking skin.

The retinoid one conversion step closer to retinoic acid than retinol, so it works at a lower percentage. It is studied for the appearance of fine lines and an even tone, and like retinol it oxidises fast in air and light.

A synthetic amino-acid derivative studied for the appearance of stubborn discoloration and a more even tone, often paired with niacinamide or acids because it works by a different route.

Tiny vesicles that carry signalling cargo between cells, the newest headline in prestige serums. The marketing is well ahead of the cosmetic evidence, which is early and mostly brand-led.

Provitamin B5, a humectant and skin conditioner used for the appearance of comfortable, hydrated, less-stressed-looking skin. It is a support ingredient, not an anti-aging active.

The lipids that make up much of the skin’s outer barrier, added to serums for the appearance of a comfortable, resilient-looking barrier and less visible dryness.

An oil-soluble exfoliating acid that can get inside the pore lining, studied for the appearance of clearer, more refined-looking pores and a smoother surface.

The smallest alpha hydroxy acid and the most-studied surface exfoliant, associated with the appearance of a smoother texture, brighter even tone and softened fine lines.

A milk-thistle-derived antioxidant, best known as the namesake active in oil-focused vitamin C serums, studied for helping skin look protected against visible environmental stress.

A purified active from Centella asiatica (cica), widely used in soothing and barrier-support serums for the appearance of calmer, more comfortable-looking skin.

A licorice-root-derived active used for the appearance of a calmer, more even tone, often included alongside stronger brighteners as a gentle supporting ingredient.

A synthetic peptide marketed as the headline active in a proprietary "trigger factor" complex, with cosmetic evidence that is early and largely limited to the brand that developed it.

A palmitoylated signal peptide (trade name Syn-Coll) used in multi-peptide anti-aging serums, studied for the appearance of firmer skin and softened fine lines.

A larger, milder alpha hydroxy acid than glycolic that also acts as a natural moisturising factor, studied for the appearance of a smoother, brighter surface with more hydration and less sting.

The largest of the common alpha hydroxy acids, derived from bitter almonds and marketed as the gentle option for the appearance of an even tone. Its evidence base is younger and thinner than glycolic or lactic.

A polyhydroxy acid, the gentlest of the exfoliating acid families, studied for the appearance of a smoother surface with very little sting. It is a large molecule that also holds water.

A compound produced by certain fungi, used in brightening formulas for the appearance of dark spots and a more even tone. It oxidises and browns readily in air and light, so packaging and freshness matter.

A water-soluble, pH-stable phosphate salt of vitamin C used as a gentler, non-stinging alternative to L-ascorbic acid, studied for antioxidant support, the appearance of brightness, and the look of blemish-prone skin.

An etherified, water-soluble vitamin C derivative that is more stable than L-ascorbic acid and converts to ascorbic acid in skin, studied for antioxidant support and the appearance of brightness and even tone.

A vitamin A ester that skin converts, by way of retinol, toward retinoic acid, used as a gentler retinoid (notably in Olay serums). It is milder than retinol and carries a lighter evidence base.

The mildest and most common vitamin A ester, several conversion steps from the active form, which makes it the weakest of the retinoids. It is stable and gentle but poorly evidenced on its own.

A filtered secretion from snails, a K-beauty essence staple, used at high percentages for the appearance of plumper, more hydrated skin. It is a mixture of glycoproteins and conditioners rather than a single active, and it is not vegan.

A water or ferment drawn from rice bran, the base of many K-beauty glow essences, used for the appearance of a brighter, more even-looking complexion. It carries starches, amino acids and antioxidants rather than one headline molecule.

The centella asiatica plant and its purified triterpenes, the cica in K-beauty soothing serums, used for the appearance of a calmer, less-reddened-looking complexion. It is one of the better-studied soothing botanicals.

A resin collected by bees, used at high percentages in glow serums for the appearance of a nourished, dewy-looking complexion. It carries flavonoid antioxidants, varies by source, and is not vegan.

A yeast-ferment filtrate, the Pitera in SK-II style essences, used at very high percentages for the appearance of a brighter, smoother-looking complexion. It is a ferment blend rich in amino acids and vitamins rather than a single active.

A lab-made or plant-expressed version of epidermal growth factor, a signalling protein, used in prestige serums for the appearance of firmer, smoother-looking skin. It is a large, fragile molecule, so stability and delivery are open questions.

An East Asian plant used at high percentages in K-beauty soothing serums for the appearance of a calmer, less-reddened-looking complexion. It sits alongside centella as a popular cica-style botanical.