The invention provides tris(hydroxymethyl)aminomethane salts of a small-molecule GLP1R agonist. The invention further provides solid compositions comprising tris(hydroxymethyl)aminomethane salts of a small-molecule GLP1R agonist. The invention further provides uses of tris(hydroxymethyl)aminomethane salts of a small-molecule GLP1R agonist, e.g., for treating type 1 diabetes, type 2 diabetes, or obesity.