Amazon.com: Pure Originial Ingredients L Carnitine Powder (4 oz) Gluten Free, Non GMO Dietary Supplement, Unflavored, No Filler or Additives : Health & Household Trimethylaminuria: Definition, symptoms, and more 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. I'm a young woman with TMAU (Fishy Odor Syndrome) does anyone have some supplements suggestions for me? Yes I've been to the doctors, specialists and psych, they tell me nothing is wrong, L Carnitine: Benefits, Uses, and Side Effects Lifespan Research Institute