Nature's Truth L Carnitine 1000mg 60 Capsules : Target Customer reviews for Nutricost L Carnitine Tartrate Supplement Powder (100 Grams) 1 Gram per Serving; 100 Servings Walmart.com Certain bodily odors are signals that something may be wrong with your health. For instance, bad breath or dark stools could indicate a digestive issue or H. Pylori infection. If you experience 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. A recurring fishy odor could indicate a larger medical problem.