Urolithin A is the end product created when bacteria in the gut break down ellagitannins, the polyphenols found in fruits such as pomegranates, strawberries, walnuts, and raspberries. The substance does not appear naturally in its end form, so we normally rely on the beneficial bacteria in the microbiome, our internal ecology of gut bacteria, to convert the polyphenols into urolithin A.
Because this compound needs a particular bacterium to create it, the bioavailability of urolithin A could vary considerably from person to person, having a greater or lesser effect depending on individual gut bacteria diversity.
Urolithin A has been a subject of interest to researchers for a while, as there have been promising early results in mice and flatworms, in which the compound increased lifespan. It appears to be geroprotective, meaning that is has age-delaying, properties.
The geroprotective effect of urolithin A appears to be focused on improving the function of the mitochondria, the power plants of our cells, which are responsible for turning nutrient-derived molecules into a form of cellular energy called adenosine triphosphate (ATP).
In a small, recent human trial, this naturally occurring compound has yielded positive results and appears to slow down part of the aging process that is related to the production of energy in our cells .
In 2020, the researchers launched their first urolithin A product, Timeline, via their company Amazentis, and have initiated further human clinical trials. Their hope is that urolithin A may be able to slow down the loss of skeletal muscle that happens with age and reduces mobility and independence.
 Andreux, P. A., Blanco-Bose, W., Ryu, D., Burdet, F., Ibberson, M., Aebischer, P., … & Rinsch, C. (2019). The mitophagy activator urolithin A is safe and induces a molecular signature of improved mitochondrial and cellular health in humans. Nature Metabolism, 1(6), 595.