In a randomized double-blind, crossover design, 12 adult volunteers with G6PD deficiency of both sexes will be supplemented with either 600 mg of alpha-lipoic acid (experimental condition - EC) or placebo (control condition - CC) every day for 4 weeks. Before intervention, all participants will be informed about the study protocol, fill a medical history questionnaire and sign an informed consent form. Moreover, measurements of anthropometric characteristics and physiological parameters, as well as a VO2max test will be performed.