Its precursors – ellagic acids and ellagitannins – are ubiquitous in nature, including edible plants, such as pomegranates, strawberries, raspberries, walnuts, and others.

[8] When synthesized and absorbed in the intestines, urolithin A enters the systemic circulation where it becomes available to tissues throughout the body where it is further subjected to additional chemical transformations (including glucuronidation, methylation, sulfation, or a combination of them) within the enterocytes and hepatocytes.

[10] In vivo studies did not determine any toxicity or specific adverse effects following dietary intake of urolithin A.

[14] Urolithin A is not known to be found in any food but rather forms as the result of transformation of ellagic acids and ellagitannins by the gut microflora in humans.

[citation needed] Sources of ellagitannins are: pomegranates, nuts, some berries (raspberries, strawberries, blackberries, cloudberries), tea, muscadine grapes, many tropical fruits, and oak-aged wines (table below).