Fatty acids are skin‑identical lipids that help build the barrier matrix in the stratum corneum. In skincare, “fatty acids” often refers to a blend of essential and non‑essential lipids—most commonly linoleic acid (omega‑6) and oleic acid (omega‑9)—used to support comfort, flexibility, and moisture retention.

Linoleic acid is frequently discussed as a key component in barrier repair because it supports a well‑organized lipid layer and can help reduce the look of dryness, rough texture, and sensitivity that come from an impaired barrier. It’s also often highlighted for oily or blemish‑prone skin because low linoleic content in skin lipids is associated with “stickier” sebum and congestion.

Oleic acid is more emollient and “cushioning,” helping soften and improve slip. In well‑balanced formulas it can enhance sensory luxury and reduce tightness, but on very acne‑prone or reactive skin, high‑oleic oils may feel too rich—so the ratio and the overall formula design matter.

Because fatty acids are fundamentally supportive rather than “aggressive,” they pair well with actives (retinoids, acids, vitamin C) by improving tolerance and reducing transepidermal water loss. Think of them as barrier‑focused conditioning agents that make results easier to live with over time.