Caffeine Solution 5% + EGCG

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

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

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 sugar-derived, biodegradable cleansing surfactant made from coconut/palm fatty alcohol and glucose; it is markedly gentler than sulfates and is the workhorse of "sensitive skin" or fragrance-free cleansers. CIR reviewed it with other alkyl glucosides and found it safe as used when the finished product is formulated to be non-irritating.

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

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 cellulose derivative used to thicken and stabilize formulas. It dissolves fully in water and does not separate or settle over time. It is well tolerated and widely used in gels, lotions, and serums.

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 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.

Dehydroacetic acid is a preservative regulated under the EU preservative annex with a set maximum concentration. Sensitization appears to be rare, though occasional contact dermatitis case reports exist, so people with reactive skin may want to patch test.

A common preservative and fragrance/solvent ingredient found naturally in many essential oils. It is well tolerated by most people at the levels used in cosmetics, but it is one of the 26 EU-designated fragrance allergens and can trigger reactions in people with an existing sensitivity.

A glycol used very widely in Korean and Western skincare as a lightweight humectant, solvent, and gentle preservative-booster, often in place of traditional preservatives. It has a low reported irritation rate at use levels and is graded low concern in published assessments.

A glycerin derivative used as a skin conditioner and preservative booster, often paired with phenoxyethanol to allow lower total preservative levels. It has a low irritation and sensitization profile in safety reviews.

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

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.