Taking L carnitine, will it improve endurance and recovery? L carnitine is a naturally occurring amino acid structure that is made in the human brain, liver, and kidneys. L carnitine plays a critical role in energy production, as it converts fat into energy. 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 Confident Sports L Carnitine Confident Health Coenzyme Q10 200mg CoQ10 with ALA and ALCAR Nature's Lab Glycine Propionyl L Carnitine & ED : Benefits, Effects & Uses Allo Health Blog