N-acyl amino acids are promising anionic amphiphilic molecules with an improved toxicological profile in comparison to the most common used sulfate-based surfactants. Previous reflectivity measurements have evidenced some differences in the interaction of N-decanoyl surfactants with the bilayer as a function of the different polar head. We observed for C10LEU the insertion of surfactant into the lipid bilayer at concentrations below CMC and a complete lipid removal at concentration double of CMC. On the contrary, C10ALA and C10SER maintained the bilayer integrity up to a concentration of three times CMC. We propose here to determine by reflectivity measurements the adsorption at the air-water interface of these compounds. This information is essential for a full understanding of the different behaviour of the analysed N-decanoyl amino acid as regards cytotoxicity and membrane interaction