Should I use L Carnitine on rest days or just before workouts? Amazon.com: Benevolent L Carnitine Supplement High Potency 1500mg L Carnitine Tartrate Fast Absorbing, Convert Fat to Energy, Support Lean Muscle, Boost Workout Performance & Metabolism 120 Vegan Capsules : Health & Household 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, 500 mg, 30 vegetarian capsules Life Extension