Polyphenols are beneficial for health, but are metabolised after consumption. We compared the vasorelaxant capacity of twenty-one physiologically relevant polyphenol metabolites in isolated mouse arteries. Hesperetin, urolithins and ferulic acid-4-O-sulfate - not their glucuronidated forms or ferulic acid - caused vasorelaxation. Therefore, we advise the use of relevant conjugates in future mechanistic research.