L Carnitine: Benefits, Side Effects, And Dosage, Per Dietitians L CARNITINE increases muscle mass, reduces fat mass. Bangkok Hospital Headquarter L Carnitine with Vitamin B5 1100 mg Orange 450 ml Beastlife L Carnitine Side Effects & Safety: A Complete Guide The Science of Good Health 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