Carnitine: Top 3 Anti Aging Benefits of This Super Nutrient Taking L carnitine, will it improve endurance and recovery? Want to level up your fat loss game? Results don't just come from training they come from strategy. GNC L Carnitine supports your body's natural fat metabolism so you can train harder, Early research into L carnitine was often cited as underwhelming, showing negligible changes in muscle carnitine content and fat loss outcomes. However, these findings may have been limited by a short study window