A-Cica 365 Soothing Relief Serum

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 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.

A light, low-odor glycol used as a solvent and humectant, extremely common in Korean toners and essences. It has a low reported irritation rate and is graded low concern in published assessments.

A humectant naturally derived from sugar beets that helps skin draw in and hold water; it has a long history of safe use with no meaningful irritation or sensitization concerns.

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

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 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 buffering agent used in tiny amounts to set a product's pH, most often alongside gel-forming polymers. It is graded low concern in published assessments at the levels used.

A gentle sugar-and-fatty-acid emulsifier that binds water and oil, favored in formulas for sensitive skin. It is well tolerated and graded low concern in published assessments.

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 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.

Carbomer is a synthetic polymer used purely to thicken and stabilize gels and lotions, with negligible skin penetration due to its large molecular size. Safety reviews have found low toxicity and minimal irritation potential even in leave-on use.

A light silicone emollient that spreads easily and gives a dry, non-greasy finish, common in Korean sunscreens and primers. It stays on the skin surface 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.

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 stable vitamin C derivative used to brighten and provide antioxidant support, more shelf-stable than pure ascorbic acid. It is generally well tolerated, though strong vitamin C forms can sting sensitive skin.

Zinc PCA is a zinc salt of a naturally occurring skin humectant, used mainly to help regulate oil and support a balanced skin microbiome in oily or acne-prone formulas. It has a long history of use with no significant reported irritation, though dedicated cosmetic-specific review data is thinner than for more common ingredients.

A purified triterpene from Centella asiatica (the "cica" plant) used in soothing and barrier-support products, especially Korean formulas. It is well tolerated with a low reported irritation rate; the strong repair and anti-aging claims around it are more marketing than settled evidence.