The Ramazzini Institute’s lifetime exposure studies on rodents exposed to aspartame and sucralose are methodologically flawed and considered unreliable by regulatory agencies due to poor study design, lack of histopathological controls, and high background tumor rates.

When rats are given very high doses of certain substances over their whole lives, these substances irritate the bladder lining and cause cells to die. The body responds by making new cells faster to replace the dead ones. Over time, this constant cycle of cell death and rapid replacement increases the chance of errors during cell division, which can lead to tumors.