THE INVENTION RELATES TO A LIQUID COMPOSITION COMPRISING A GLP-1 AGONIST OR/AND A PHARMACOLOGICALLY TOLERABLE SALT THEREOF AND OPTIONALLY AT LEAST ONE PHARMACEUTICALLY ACCEPTABLE ADJUVANT. THE LIQUID COMPOSITION IS CHARACTERISED IN THAT IT CONTAINS METHIONINE, OPTIONALLY AS ADD-ON THERAPY WITH METFORMIN AND/OR LONG-ACTING INSULINS/INSULIN DERIVATIVES.