L Carnitine Tablets for Energy Support Nature's Bounty GNC L Arginine & L Citrulline 500 mg 500 mg 120 Caplets (120 Servings) GNC L Arginine Benefits L Arginine Amino Acid Supplements Did you know L carnitine, a vital amino acid, is naturally produced by your body and found in various foods? While acetyl L carnitine (ALCAR) can be a beneficial supplement for some, most people get The Effects of Consuming Amino Acids L Arginine, L Citrulline (and Their Combination) as a Beverage or Powder, on Athletic and Physical Performance: A Systematic Review