A global analytical control of dietary supplements has become essential. In this field, additives containing amino acids (AAs) are of growing interest in the food industry. AAs are important in human nutrition and in maintaining health; they play a key role in metabolizing nutrients, building muscle tissue and protecting the body against disease. The preferred methods for their quality control use chromatographic techniques, which are often difficult to set up and not really adapted to the characterization and quantification of other ingredients and contaminants in commercial formulations. In this study, we demonstrated the efficiency of a combined Mass Spectrometry-Nuclear Magnetic Resonance (MS-NMR) approach for the qualitative and quantitative analysis of home-made and commercial AA supplements (Amino 75 (R), Primene (R) 10% and BCAA + Glutamine Advanced (R)). The proposed workflow enables the quantification of AAs and other components at concentrations of less than 1 mM with tolerances of +/- 10% for NMR and +/- 20% for MS, which correspond to European recommendations. In our work, we point out the complementarity of MS and NMR for a global and stringent analysis of food supplement content. (C) 2018 Elsevier Ltd. All rights reserved.