The Right Way to Take L Carnitine to Boost Your Training Oxyenergys L Carnitine. My go to pre post workout supplement. Pre workout I usually take it before my workout session for energy production. Post workout Ill take it the day after my workout L Carnitine as Pre Workout Supplement: Guide The Science of Good Health The Right Way to Take L Carnitine to Boost Your Training L Carnitine Before or After Workout Which Is Better for Fat Loss ? When Should You Take L Carnitine? MuscleTech