Common Name(s): Octadecenedioic acid,octadecenedioic acid,c18 unsaturated diacid,long-chain dicarboxylic acid
CAS Number: 871-70-5
DESCRIPTION
What It Does: Helps balance oily skin by normalizing sebum production and provides mild antimicrobial action. works to smooth and condition skin texture.
Why It's Used: Octadecenedioic acid is selected for its long-chain c18 bifunctional diacid architecture — the two terminal carboxylate groups enable chelation of metal ions and inhibition of microbial enzymes while the c18 chain provides sc-compatible lipid emolliency, combining antimicrobial, conditioning, and sebum-normalizing activity in a single molecule.
How It Works: C18 dicarboxylate bifunctional acid; carboxylate groups → microbial enzyme inhibition via competitive chelation; c18 unsaturated chain → sc lipid integration; sebum interaction → normalization of sebaceous activity.
Typically Found In: Acne care,sebum control products,skin brightening
TECHNICAL DETAILS
Primary Category: Functional ingredient – skin conditioning agent
Secondary Functions: Antimicrobial support,sebum normalization
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.5%–5%
SOURCING & ETHICS
Vegan Status: Yes
Halal Status: Yes
Source Notes: Plant-derived (biooxidation of oleic acid) or synthetic.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 – very low
Comedogenicity Rating: 0/5 – non-comedogenic
Sensitivity Concerns: Generally well tolerated. ph adjustment may be required in formulation.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Good safety profile. ewg score: 1–2.
Works Well With: Niacinamide,salicylic acid,zinc compounds
Avoid Combining With: No significant incompatibilities
SCIENTIFIC NOTE
C18 dicarboxylic acids inhibit malassezia sebum esterases via competitive substrate mimicry — the bifunctional diacid differs from the monocarboxylic natural fatty acid substrate, disrupting fungal lipase activity that drives sebum overproduction.
Last Verified: 2026-03-27
Primary Sources: Cosing database,octadecenedioic acid long-chain diacid skin review