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. Breakthrough in studying the enzyme that ultimately produces fish odor syndrome EurekAlert! L carnitine supplements can cause a fishy odor in the breath, sweat, and urine. This is likely due to the formation of trimethylamine (TMA). TMA is also responsible for the pungent smell of L Carnitine (NZ) Health & Balance Vitamins Trimethylaminuria (Fish Odor Syndrome or TMAU) L Carnitine Avoid Fishy Smell TikTok