The Chemistry of Bad Smell Explained 1 Cadaverine Odor: Smell of decomposing dead bodies Chemical type: Diamine Formula idea: HN(CH)NH Source: Produced when proteins break down during decomposition Why it Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum Trimethylaminuria (Fish Odor Syndrome or TMAU) Does Carnitine Cause Body Odor? Lume Deodorant Did You Know? Some people report a fishy smell after supplementing with L carnitine. This happens because certain gut bacteria convert carnitine to trimethylamine, a malodorous compound found in rotting fish.