What is L Carnitine? L Carnitine is a naturally occurring amino acid derivative that the human body can synthesize itself. It is mainly found in red meat and dairy products. [1] Core Benefits of L Carnitine Vitamin Supplement for Energy and Metabolism Boost What even is carnitine?? Carnitine is a "conditionally" essential amino acid that becomes essential during pregnancy. What does this mean? You must get carnitine through food! The best sources are red Amazon.com: Doctor's Best L Carnitine Fumarate Supplement for Men & Women L Carnitine Fumarate with Biosint Carnitines Capsules, Helps Convert Fat into Usable Energy, Non GMO, Gluten Free, Vegan 60 Veg Caps : Nutricost L Carnitine Tartrate Supplement, 240 Capsules, 500mg, 1000mg per Serving Walmart.com