Octadecenedioic Acid Good Antioxidant Anti-Blemish Dark Spot Fading Evens Skin Tone Octadecenedioic Acid at a glance Olive-derived compound known as a carboxylic acid Plays a novel role in helping to fade discolorations Uncommon to see in cosmetics, but not known to be a problem for skin May play a role in helping skin feel smoother Octadecenedioic Acid description Octadecenedioic acid is a carboxylic acid, which refers to a group of acids whose carbon and oxygen atoms are double bonded to a single-bonded hydrogen-oxygen combination. Carboxylic acids have a wide variety of uses in cosmetics, from smoothing and softening skin to easing redness and providing antimicrobial properties that help keep a cosmetic safe from contaminants. Back to octadecenedioic acid, which is often referred to the scientific research as 9-octadecenedioic acid: it’s plant-derived (from olives) and studies show it plays a novel role in interrupting excess melanin via binding to enzymatic receptor sites on skin’s surface that help encourage normal, even skin color. The recommended usage level for octadecenedioic acid in skin care with the goal of improving dark spots is 2%. Although this is a promising ingredient, it’s rarely used in cosmetics; however, it’s not known to be problematic for skin.