Amazon.com: Ronnie Coleman Signature Series L Carnitine XS 3000 Liquid, Amino Acids Metabolism and Lean Muscle Strength Support, Stimulant Free, Sugar Free, Zero Carbs, Orange Smash, 16 Oz : Health & Household 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 Levocarnitine IV L Carnitine Linus Pauling Institute Oregon State University Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis Urine normally has a slight smell, but some unusual and strong smells may be a sign that something's wrong.