A 16-week study published in the Journal of Child and Adolescent Psychopharmacology (2007; 17(6):791–802) involved 112 children with ADHD and examined the effects of supplementation with acetyl-L-carnitine. The children were randomly assigned to receive either a placebo or the supplement, with dosage based on body weight. Acetyl-L-carnitine was found to be beneficial for children with the inattentive subtype of ADHD, but it was not beneficial for children with the combined subtype.
Another small study, published in Prostaglandins, Leukotrienes and Essential Fatty Acids (2002; 67(1):33–38), involved 24 boys who received L-carnitine at a dosage of 100 mg/kg of body weight. The boys were divided into two groups, with one group receiving the supplement. Outcomes were evaluated using the Child Behavior Checklist. Supplementation with L-carnitine was associated with reductions in inattentiveness and aggressive behavior.
Both studies were small and should be considered pilot-level research. Nevertheless, they suggest potential benefits in certain subgroups of children with ADHD. L-carnitine plays an important role in cellular energy production by enhancing fat oxidation within the mitochondria, which may help explain its effects on attention and behavior.
