Trimethylamine N-oxide Trimethylamine N-oxide Trimethylamine "N"-oxide (TMAO) is an organic compound with the formula (CH)NO. It is in the class of amine oxides. Although the anhydrous compound is known, trimethylamine "N"-oxide is usually encountered as the dihydrate. It is a product of the oxidation of trimethylamine, a common metabolite in animals. Both the anhydrous and hydrated materials are white, water-soluble solids. Trimethylamine "N"-oxide is an osmolyte found in saltwater fishes, sharks, rays, molluscs, and crustaceans. It is considered as a protein stabilizer that may serve to counteract urea, the major osmolyte of sharks, skates and rays. It is also higher in deep-sea
U Should've Known Better backbeat, the song's instrumentation consists of screeching guitars and an understated harp pattern. Lyrically, Monica, as the protagonist, delivers a message of loyalty to her imprisoned love interest and sings about staying down for him despite his doubts. The song was generally well received by contemporary music critics who highlighted the heartfelt emotion and sadness. Released as the fourth and final single from "After the Storm" in May 2004, the single marked Monica's first balladic release in over five years. On the charts, "U Should've Known Better" peaked at number 19 on the US "Billboard" Hot 100 and number 6