Acetyl-L-carnitine (ALC) in attention-deficit/hyperactivity disorder: a multi-site, placebo-controlled pilot trial

J Child Adolesc Psychopharmacol. 2007 Dec;17(6):791-802. doi: 10.1089/cap.2007.018.


Objective: To determine whether acetyl-L-carnitine (ALC), a metabolite necessary for energy metabolism and essential fatty acid anabolism, might help attention-deficit/hyperactivity disorder (ADHD). Trials in Down's syndrome, migraine, and Alzheimer's disease showed benefit for attention. A preliminary trial in ADHD using L-carnitine reported significant benefit.

Method: A multi-site 16-week pilot study randomized 112 children (83 boys, 29 girls) age 5-12 with systematically diagnosed ADHD to placebo or ALC in weight-based doses from 500 to 1500 mg b.i.d. The 2001 revisions of the Conners' parent and teacher scales (including DSM-IV ADHD symptoms) were administered at baseline, 8, 12, and 16 weeks. Analyses were ANOVA of change from baseline to 16 weeks with treatment, center, and treatment-by-center interaction as independent variables.

Results: The primary intent-to-treat analysis, of 9 DSM-IV teacher-rated inattentive symptoms, was not significant. However, secondary analyses were interesting. There was significant (p = 0.02) moderation by subtype: superiority of ALC over placebo in the inattentive type, with an opposite tendency in combined type. There was also a geographic effect (p = 0.047). Side effects were negligible; electrocardiograms, lab work, and physical exam unremarkable.

Conclusion: ALC appears safe, but with no effect on the overall ADHD population (especially combined type). It deserves further exploration for possible benefit specifically in the inattentive type.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcarnitine / adverse effects
  • Acetylcarnitine / therapeutic use*
  • Analysis of Variance
  • Attention Deficit Disorder with Hyperactivity / drug therapy*
  • Attention Deficit Disorder with Hyperactivity / physiopathology
  • Child
  • Child, Preschool
  • Electrocardiography
  • Faculty
  • Female
  • Humans
  • Male
  • Nootropic Agents / adverse effects
  • Nootropic Agents / therapeutic use*
  • Parents
  • Pilot Projects
  • Psychiatric Status Rating Scales
  • Time Factors
  • Treatment Outcome


  • Nootropic Agents
  • Acetylcarnitine