Metformin hydrochloride (MET–HCl) is a widely prescribed antihyperglycemic drug for the non-insulin-dependent diabetes mellitus treatment. Since the prolonged use of MET–HCl may cause gastrointestinal intolerance, we have focused on expanding the solid-state landscape of MET, designing three novel MET salts with saccharin, maleic and malonic acids. These multicomponent systems named metformin maleate (MET–MAL), metformin malonate (MET–MLN), and metformin saccharinate (MET–SAC) have been prepared via supramolecular synthesis by slow evaporation method and characterized by X-ray diffraction (SCXRD, PXRD), spectroscopic (FT-IR and ¹H NMR) and thermal (TG, DSC, HSM) techniques. The biopharmaceutical profile of these salts, including the MET–HCl, has been assessed. All of them were less soluble, with a slower dissolution rate, and with a resemble permeation capacity over MET–HCl. These results demonstrate the potential of these solid forms regarding the enhanced API candidates for new antidiabetic solid formulations.