Amazon.com: Muscle Pharm L Carnitine 3000, The Ultimate Liquid L Carnitine Supplement for High Performance, Supports Metabolism, Hydration & Energy, Zero Sugar, Low Calories, Peach Nectarine Flavor, 32 Servings : Everything Else 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. L Carnitine injection is recommended at 1 ampule every 2 3 days for best results. The L Carnitine is taken intravenously either by normal injection or using a butterfly needle. After taking this L Carnitine, you 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