Nootropic Food supplement Gluten free Vegan non-GMO Supports energy metabolism Supports alertness and mental focus Acetyl L-carnitine (ALC) is a nutrient and naturally occurring metabolite in the human body that is involved in macronutrient metabolism. Deficiencies in L-carnitine can increase fatigue and decrease recovery rate following physical activity. A number of tissues contain significant concentrations of ALC but these decrease as we age and there is evidence that dietary supplementation can address these shortfalls.