Injectable L Carnitine: What It Is, How It Works, and Who Should Use It Mesotherapy Cocktails, Exosomes Regenerative Skin Boosters Should I use L Carnitine on rest days or just before workouts? L Carnitine is an amino acid that plays a role in energy production, by helping transport fatty acids into the mitochondria. Mitochondria are tiny powerhouses within cells that make energy. Liquid Gold: 5 Benefits of Liquid Carnitine You Can't Ignore NutraBio Brands L Carnitine Benefits, Uses, Dosage, Foods, Side Effects Dr. Axe