L Carnitine: Benefits, Side Effects, And Dosage, Per Dietitians Supplement of the week: L Carnitine! This one doesn't just boost fat metabolismit can also improve recovery, endurance, and even brain function. If you're serious about performance and longevity, this might be L Carnitine: Benefits, Uses, Side Effects, and More Acetyl L Carnitine Powder 150g Applied Nutrition H&B Liquid L Carnitine 1500, Blue Raspberry, 16 oz (473 ml)