18-MEA. An essential fatty acid for hair health
Among the active ingredients naturally present on the surface of hair, 18-methyleicosanoic acid (18-MEA) remains little known. Yet, its role is fundamental in maintaining the integrity and protection of the hair fiber, regardless of its texture.
A naturally occurring component… but fragile.
18-MEA is a fatty acid derived from lipids naturally synthesized by the scalp. It is found specifically on the surface of the cuticle—the hair's protective outer layer. What makes it special? It forms a sort of hydrophobic lipid film that acts as a natural barrier against external aggressions: friction, washing, pollution, and humidity.
But this protective layer is vulnerable. Repeated exposure to harsh shampoos, chemical dyes, or even heat can degrade or eliminate 18-MEA. Without it, the fiber loses its suppleness, becomes more porous, and therefore more susceptible to breakage and dryness.
A key role in hair balance.
What makes 18-MEA so unique is its ability to reduce friction between hair fibers. This phenomenon is essential: less friction means less breakage, fewer tangles, and easier detangling—especially for curly, coily, or kinky textures, which are often more prone to mechanical friction.
From a scientific point of view, recent studies confirm that the presence of 18-MEA also helps maintain cellular cohesion of the cuticle . In other words: it helps the scales to remain well aligned, which promotes better light reflection and a feeling of softness to the touch – without the addition of film-forming or occlusive agents.
Restoring 18-MEA: a hair health issue.
The loss of 18-MEA is not irreversible. Certain hair care routines, enriched with biomimetic or lipid-replenishing ingredients, can help compensate for this loss. The issue isn't purely aesthetic: it's about preserving the hair's barrier function , which is essential to its healthy physiological state.
At Möss, we incorporate this insight into our approach: formulating specific treatments to preserve the lipid ecosystem of each fiber. By respecting the diversity of textures, we consider the unique needs of each hair to strengthen what it naturally produces.
In summary.
18-MEA is a key marker of hair health. Occurring naturally, it provides essential protection against stressors. Fragile yet fundamental, it deserves our full attention. Taking care of its presence offers hair greater resilience, greater softness, and lasting balance.
Sources:
Degradation of Hair Surface: Importance of 18-MEA and Epicuticle, Tokunaga, S.; Tanamachi, H.; Ishikawa, K. Degradation of Hair Surface: Importance of 18-MEA and Epicuticle. Cosmetics 2019 , 6 , 31
Song, SH., Park, H., Lim, B. et al. Biomimetics through bioconjugation of 16-methylheptadecanoic acid to damaged hair for hair barrier recovery. SciRep 14 , 27387 (2024)
