By promoting the synthesis of phospholipids in vivo, betaine on the one hand reduces the activity of fat synthase in liver, on the other hand promotes the synthesis of apolipoprotein in liver, promotes the migration of fat in liver, reduces the content of triglyceride in liver, and effectively prevents the accumulation of fat in liver. It can reduce the deposition of body fat by promoting the decomposition of fat and inhibiting the synthesis of fat.

Betaine is an ideal food attractant because of its sweet and sensitive umami taste, chemical structure suitable for fish olfactory and taste receptors, and enhancing the taste perception effect of other amino acids. Researchers at Boston University measured chemoreceptor coordination in the legs of crayfish and found that betaine was the biggest irritant. Adding 0.1% to 0.3% betaine into the feed can strongly stimulate the sense of smell and taste of all fish and shrimps and other crustaceans. The results also showed that betaine had good alluring effect on sense of smell and taste of macrobrachium rosenbergii.

Betaine is a buffer against osmotic shock. When the osmotic pressure outside the cell changes dramatically, the cell can absorb betaine from the outside to maintain the normal osmotic pressure balance, and prevent the diversion of water in the cell and the invasion of salts. At the same time, betaine can improve the function of potassium and sodium pump of cell membrane, which can ensure the normal function and nutrient absorption of intestinal mucosal cells. The buffering effect of betaine on osmotic shock plays an important role in maintaining normal physiological functions under stress conditions such as diarrhea of piglets, water change and molting of aquatic animals.