High Potency Classics Face Firming Serum

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

A sulfur-containing antioxidant that functions both inside and outside cells, studied for anti-aging effects in cosmetics. Published safety assessments support low irritation at typical cosmetic concentrations, though some users may experience mild irritation or sensitivity at higher doses or when combined with other active ingredients.

A palm/coconut-derived fatty ester used to soften skin and help dissolve oil-soluble UV filters. It sits fairly high on lab comedogenicity scales, so some acne-prone users report clogged pores, though this does not translate into a broader safety concern for general use.

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.

The smallest and most penetrating alpha hydroxy acid, used to loosen the bonds between dead skin cells for smoother texture and tone. It is a genuine irritant at higher concentrations or low pH, can increase sun sensitivity, and the EU restricts free acid content and requires sunscreen-use wording on labeling.

A solvent and penetration enhancer derived from isosorbide that helps active ingredients absorb into skin. Used at low levels in targeted treatments, it is well tolerated at cosmetic concentrations.

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 common emulsifier and texture-softener made from glycerin and stearic acid. CIR review of this class found no evidence of reproductive, carcinogenic, sensitizing, or phototoxic effects in the studies examined.

A PEG-based emulsifier that blends oils and water in formulas. It is a workhorse ingredient in stable emulsions and is approved for cosmetic use. Well tolerated.

A natural component of skin's own moisturizing system, used at low percentages as a humectant and at higher percentages (10 percent plus) as a mild keratolytic for very dry or rough skin. It can sting broken or eczema-prone skin, especially at higher concentrations.

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.

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.

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

A small-dose synthetic antioxidant that prevents oils and fragrance in a formula from oxidizing. Not shown to pose a toxicological risk at the levels used in cosmetics.

A chelating agent that binds trace metal ions to keep formulas stable and preservatives working properly. It is not a functional skincare "active" and only a very small amount is used, with minimal skin penetration expected.

A PEG-type emulsifier (ethoxylated cetearyl alcohol) that helps blend the water and oil parts of a cream. CIR concluded ceteareth ingredients are safe as used, with the one caveat that they are not meant for broken or damaged skin.

A synthetic polymer used to thicken and stabilize water-based formulas like gels and serums. It provides texture and suspension of particles without interfering with skin feel. Well established in cosmetics.

A silicone that gives a smooth, soft feel and helps hold water in the skin. Inert and well studied.

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.

A widely used preservative, safe at the legal limit of 1% or less. Often the "paraben-free" replacement.

A widely used, gentle preservative also common in food. It is generally well tolerated, though it can occasionally cause mild, transient irritation in people with already-compromised or very reactive skin.

An undisclosed scent blend that can contain dozens of components. The single most common cause of cosmetic contact allergy, and the blend is not itemized, so you cannot see what is in it.

A natural fragrance component found in citrus oils and lemongrass, giving a lemony scent. It is a named EU fragrance allergen that can oxidize into potent contact allergens over time; people with known fragrance sensitivities may react.

A rose-scented fragrance ingredient found naturally in geranium and rose oil. It is one of the 26 fragrance allergens the EU requires to be labeled by name because a minority of people develop skin sensitization to it, though most users tolerate it without issue.

A floral, rose-like fragrance compound found in many essential oils. It is one of the 26 EU-designated fragrance allergens, meaning a documented minority of people can develop contact sensitization, so brands must disclose it above set thresholds.

A citrus-scented fragrance component. Fine for most, but it oxidizes over time into a known contact allergen, so it must be labelled in the EU.

A floral fragrance component and one of the EU-labelled fragrance allergens. Usually fine, worth watching if you react to scented products.