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 Acetyl L Carnitine: Benefits, Forms, Dosing, and Side Effects Dr Brad Stanfield What are the benefits of carnitine? Ask Huberman Lab L Carnitine is Underrated. New Meta Review Reminds Us Why.