Creatine & Acetyl L Carnitine Energy Plus, 0.51 lb Life Extension Acetyl L Carnitine is a modified form of carnitine that has the dual benefit of supporting mental fatigue, improving mood levels and alertness as it crosses the blood brain barrier with ease while supporting Acetyl L Carnitine 500 mg 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