Because amino acids are compounds with high solubility inwater, the sample treatment was accomplished using water asextractant. Trying to study the number of extractions, the recov-eries of the samples were calculated after 2–5 water treatments. Inthe case of two and three repetitions, recovery values lower than90% were achieved for all the samples. Meanwhile, with four extrac-tions, recoveries till 99% for Phe, 90% for Tyr and 94% for Trp wereattained for a standard content of 80 g/mL for each amino acid.Thus, and due to the fact that more extractions did not reached bet-ter recoveries, four extractions were considered for the treatmentof the food supplements.