18-MEA: This little-known elixir, an essential fatty acid for hair health

Among the active ingredients naturally present on the hair's surface, 18-methyleicosanoic acid (18-MEA) remains little known. Sadly, perhaps because of its name, its role is fundamental in maintaining the integrity and protection of the hair fiber, regardless of its texture.

A naturally occurring component on the hair fiber... 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 protective outer layer of the hair. Its peculiarity? It forms a kind of hydrophobic lipid film that acts as a natural barrier against external aggressions: friction, washing, pollution, humidity.

But this protective layer is vulnerable. Repeated exposure to aggressive shampoos, chemical dyes, or 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, frizzy, or coily 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 contributes to maintaining the cellular cohesion of the cuticle. In other words, it helps the scales stay well-aligned, which promotes better light reflection and a soft feel to the touch – without the addition of film-forming or occlusive agents like silicones.

Restoring 18-MEA: a hair health challenge.

To compensate for the lack of 18-MEA, certain hair routines, enriched with biomimetic or lipid-replenishing ingredients, can help. The challenge is not purely aesthetic: it is about preserving the hair's barrier function, essential for its good physiological condition.

At Möss, we integrate this data into our approach: formulating specific treatments to preserve the lipid ecosystem of each fiber. By respecting the diversity of textures, we take into account the unique needs of each hair type to strengthen what it naturally produces.

In summary.

18-MEA is a key marker of hair health. Naturally present, it provides essential protection against aggressions. Fragile but fundamental, it deserves all our attention. Taking care of its presence means offering hair better 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. Sci Rep 14, 27387 (2024)