The Hydro Layer

The base most products are built on. It carries the other ingredients and has no safety concern.

A stable, saturated version of squalene, a lipid the skin already produces, now usually sourced from olives or sugarcane instead of shark liver. It is very well tolerated across skin types and helps reinforce the skin barrier.

A probiotic-derived ferment lysate containing amino acids and polysaccharides. Limited published research suggests it may benefit skin hydration, though the cosmetic evidence base is smaller than for established ingredients.

A blend of cetyl and stearyl fatty alcohols used to thicken lotions and soften skin. It is chemically unrelated to drying alcohols like ethanol, and the CIR expert panel has found fatty alcohols safe as used in cosmetics.

A humectant that draws water into the skin. One of the best-studied, best-tolerated ingredients in personal care.

A form of vitamin B3 used to support a more even-looking tone and a comfortable barrier. Well tolerated at cosmetic levels.

A lightweight, silicone-like emollient derived from coconut/palm fatty alcohols, used to give lotions a smoother, less greasy feel. Listed in the EU CosIng database as a skin-conditioning agent with no restrictions.

A five-carbon alcohol used as a humectant to draw moisture into the skin and help formulations remain stable. It is well tolerated in the concentrations used in cosmetics.

The sodium salt of benzoic acid, used as a preservative in both foods and cosmetics. Decades of safety review support its use at typical cosmetic concentrations, with mild irritation the main reported issue in sensitive skin.

A corn-derived solvent and humectant that has largely replaced propylene glycol in "clean" formulas; CIR reviewed the alkane diol group and found use concentrations up to about 40 percent in leave-on products like deodorant sticks with no meaningful irritation signal.

A chemically cross-linked form of sodium hyaluronate designed to remain on the skin surface longer and provide sustained hydration. It functions as a humectant and is well tolerated, with the same safety profile as standard hyaluronic acid.

Derived from olive oil fatty acids, this PEG-free emulsifier is used at low concentrations to hold water and oil phases together in creams. Available safety and dermatological testing has not shown meaningful irritation or sensitization at use levels.

A light coconut-derived emollient ester used as a natural-feeling alternative to silicones, giving a dry, velvety finish. It is well tolerated and graded low concern in published assessments.

A phospholipid emulsifier from soy or sunflower that binds water and oil and helps other ingredients absorb. It is a natural component of skin membranes, well tolerated, and reviewed as safe as used; a soy-derived grade is not a meaningful concern for a soy food allergy because the protein is largely absent.

An olive-oil-derived emulsifier, almost always paired with cetearyl olivate, that holds water and oil together and leaves a light skin-like finish. It is well tolerated and graded low concern in published assessments.

A lightweight, odorless emollient made by combining coconut or palm-derived fatty acids with glycerin. It spreads easily, feels non-greasy, and has a long history of use in skin and hair products with no meaningful irritation or sensitization signal.

An antioxidant that helps protect a formula and condition skin. Well tolerated.

Used in tiny amounts to set a product to skin-friendly pH. No concern at those levels.

A polyol (sugar alcohol) that attracts water to the skin. Like sorbitol and glycerin, it is well tolerated in skincare formulas. It is commonly used to boost hydration without the stickiness of other humectants.

Pentylene glycol is a humectant and solvent that also offers mild antimicrobial support in formulas. It is generally well tolerated, with only rare reports of irritation, mostly in already sensitive or compromised skin.

A lab-made version of a lipid naturally found in the outer skin barrier. It is added to creams and cleansers to help replace lipids that washing can strip away, and it is not linked to irritation or safety concerns.

A linoleic-acid-rich plant oil used as an emollient and, in some small pediatric studies, associated with support of the skin barrier when applied to infant skin. It is well tolerated with a low reported rate of contact reactions.

A mild plant-derived emulsifier combining polyglycerol and lauric acid. Used in gentle formulas to blend oil and water phases; well tolerated across skin types at cosmetic concentrations.

A lightweight humectant and solvent similar in role to propylene glycol, used to carry actives and give lotions a lighter feel. CIR has reviewed it and considers it safe as used in cosmetics.

Caprylyl glycol is a plant-derived humectant that also has mild antimicrobial properties, so it is commonly paired with other preservatives to allow lower overall preservative levels. Available data do not point to meaningful irritation or sensitization concerns at typical use levels.

An amino acid polymer derived from glutamic acid that functions as a humectant to draw moisture into skin. It is graded with no known concerns in cosmetic use and is well tolerated across skin types.

A humectant that holds water at the skin surface for a more hydrated look. No safety concern.

A larger, gentler alpha hydroxy acid than glycolic acid, used to exfoliate and to draw in moisture. It can still cause stinging or increased sun sensitivity at higher concentrations, so daytime SPF use is sensible, but it is generally better tolerated than glycolic acid.

A small glycol used as a solvent and to boost the absorption of actives, and to help preservatives work at lower levels. It is well tolerated and graded low concern in published assessments.

Xanthan gum is a microbial-fermentation-derived polysaccharide used to thicken and stabilize textures, similarly common in food. Cosmetic panel review of this and related microbial gums found them safe as used, with no meaningful irritation signal at typical concentrations.

Gluconolactone is a polyhydroxy acid that exfoliates gently while also acting as a humectant and mild antioxidant, and it is generally recommended for sensitive or barrier-compromised skin over smaller AHAs. A full cosmetic panel review found it safe as used, though some users still report mild stinging or redness at higher concentrations.

A starch breakdown product used as a thickener and texture modifier in cosmetic formulations. It is well established in cosmetics and food applications with documented low irritation and contact sensitization risk across diverse skin types.

A synthetic peptide sequence derived from or mimicking Epidermal Growth Factor, designed to support skin renewal and healing. Cosmetic-grade formulations show no systemic absorption at recommended levels and are well tolerated in topical use.