Akkermansia muciniphila is a potential probiotic candidate for ameliorating metabolic diseases. This review discusses the abundance changes of A. muciniphila in metabolic diseases and its mechanisms in treating obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD), and non-alcoholic fatty liver disease (NAFLD). A. muciniphila is a Gram-negative, strictly anaerobic bacterium that resides in the mucus layer of the gastrointestinal tract. It has a unique ability to degrade mucin, which is its sole carbon and nitrogen source. A. muciniphila is highly abundant in the intestinal tract, accounting for approximately 1% to 4% of the total intestinal microbiota. Its abundance is influenced by age, diet, disease, and antibiotics. Studies have shown that A. muciniphila abundance is reduced in individuals with obesity, T2DM, CVD, and NAFLD. However, some studies have found that A. muciniphila abundance is increased in these conditions. A. muciniphila has been shown to alleviate obesity, T2DM, CVD, and NAFLD by improving intestinal barrier function, reducing inflammation, and modulating gut microbiota. It also promotes the production of short-chain fatty acids, which have anti-inflammatory and metabolic benefits. A. muciniphila can also reduce the levels of trimethylamine (TMA) and trimethylamine N-oxide (TMAO), which are associated with CVD. A. muciniphila has been shown to reduce the accumulation of fat in the liver, which is a key factor in NAFLD. However, the exact mechanisms by which A. muciniphila alleviates these diseases are not fully understood. Current research suggests that A. muciniphila has the potential to be a next-generation probiotic for the treatment of metabolic diseases. However, further studies are needed to fully understand its mechanisms and to develop effective therapies.Akkermansia muciniphila is a potential probiotic candidate for ameliorating metabolic diseases. This review discusses the abundance changes of A. muciniphila in metabolic diseases and its mechanisms in treating obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD), and non-alcoholic fatty liver disease (NAFLD). A. muciniphila is a Gram-negative, strictly anaerobic bacterium that resides in the mucus layer of the gastrointestinal tract. It has a unique ability to degrade mucin, which is its sole carbon and nitrogen source. A. muciniphila is highly abundant in the intestinal tract, accounting for approximately 1% to 4% of the total intestinal microbiota. Its abundance is influenced by age, diet, disease, and antibiotics. Studies have shown that A. muciniphila abundance is reduced in individuals with obesity, T2DM, CVD, and NAFLD. However, some studies have found that A. muciniphila abundance is increased in these conditions. A. muciniphila has been shown to alleviate obesity, T2DM, CVD, and NAFLD by improving intestinal barrier function, reducing inflammation, and modulating gut microbiota. It also promotes the production of short-chain fatty acids, which have anti-inflammatory and metabolic benefits. A. muciniphila can also reduce the levels of trimethylamine (TMA) and trimethylamine N-oxide (TMAO), which are associated with CVD. A. muciniphila has been shown to reduce the accumulation of fat in the liver, which is a key factor in NAFLD. However, the exact mechanisms by which A. muciniphila alleviates these diseases are not fully understood. Current research suggests that A. muciniphila has the potential to be a next-generation probiotic for the treatment of metabolic diseases. However, further studies are needed to fully understand its mechanisms and to develop effective therapies.