Abstract: The invention relates to a method for obtaining thymosins and/or the pharmaceutically acceptable salts thereof by means of solid-phase synthesis on polymeric supports, which comprises the steps of linearly synthesizing the thymus-derived peptides in solid phase, incorporating at least one Thr or Ser in the sequence, in pseudoproline dipeptide form, obtaining the thymosins by treating the peptidyl resin with trifluoroacetic acid, and purifying the thymosins by RP-HPLC. The present invention also protects the isolated and/or purified compound obtained by means of said method and also the use thereof in the preparation of a medicinal product.