L Theanine Vs L Carnitine: Can We Combine Them? Vinatura Supplements L Carnitine: Benefits, Side Effects, And Dosage, Per Dietitians L Carnitine Supplements Nature's Best 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 Add it to any drink and feel the glow from inside and out.