Potassium 1H-indol-3-yl sulfate is a metabolite of tryptophan, produced by intestinal microorganisms and combined with sulfate in the liver before entering the circulatory system. Potassium 1H-indol-3-yl sulfate is a potent endogenous agonist of the aryl hydrocarbon receptor (AhR) and a urinary toxin. Potassium 1H-indol-3-yl sulfate can be used for research on kidney diseases[1][2].