L Carnitine (Orange) Outlastlabz L Carnitine is an amino acid that supports weight loss as it is a fat burning supplement. L Carnitine Push is a direct and quick IV infusion procedure that can be done on a weekly CARNITINE (L CARNITINE, ACETYLCARNITINE) Neuroneeds L Carnitine: Benefits, Side Effects, And Dosage, Per Dietitians 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.