Acetyl L Carnitine L Carnitine for building Muscle Mass Carnipure L Carnitine 3000 Fat Burner Weight Loss for Men & Women Mymealo Parker Naturals L Carnitine 5000 Mg Premium Dietary Supplement Liquid Parker Naturals 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