Is L Carnitine safe for athletes at doses up to 6000 mg day? Consensus Acetyl L Carnitine Supplement: Uses, Benefits, Side Effects, Dosage, A Welltopia Pharmacy Carnitine and acetyl L carnitine Neuroneeds If you are like a lot of people, you may have never heard of carnitine but this important nutrient is critical for our body's ability to optimally burn fat required for energy.