Thorne Research L Carnitine L Carnitine Supplement The Natural Athletes Clinic 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 Empower Functional Health Dr Peptides L Carnitine 600mg For Research use only Research Science Update L Carnitine L Tartrate Supplementation Impr Prosource Acetyl L Carnitine 500mg (Allergy Research Group)