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 Amazon.com: Nutricost Acetyl L Carnitine (ALCAR) 500mg, 180 Capsules, 180 Servings Non GMO and Gluten Free, 1 Capsule per Serving : Everything Else Carnitine Blend Rootcology Does Carnitine Cause Body Odor? Lume Deodorant L Carnitine: Benefits, Uses, and Side Effects Lifespan Research Institute Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis