All livers contain some fat. Normal fat levels in the liver are between 5 and 10 percent. If your liver has more fat than that, you may have fatty liver disease. MASH is a more severe form of fatty liver disease, which can begin as nonalcoholic fatty liver disease (NAFLD), also called metabolic dysfunction-associated steatotic liver disease (MASLD).
MASH causes your liver to become swollen and damaged. Over time, MASH can decrease liver function. As the liver tries to repair and replace damaged cells, the healing process can leave behind scar tissue. If the liver gets scared enough, it cannot work properly. This is known as cirrhosis of the liver. MASH can also lead to liver cancer or liver failure.
About 25% of people with MASLD go on to develop MASH.