carnitine Archives Genetic Lifehacks 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. Acetyl L Carnitine: Benefits and Side Effects Gene Food Trimethylaminuria: Definition, symptoms, and more 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: Unveiling the Science Behind its Role in Effective Weight Loss Aesthetics 360 Lash & MedSpa