Acetyl L-Carnitine & ADHD

Acetyl L-carnitine is a naturally occurring molecule that exists in a variety of plants and animals. Health companies also sell it as a dietary supplement. It's one form of another molecule known as L-carnitine, which helps the human body convert fat into energy. The studies that examine the effects of acetyl L-carnitine on the symptoms of ADHD are limited, but they do show some promise.

ADHD

Attention deficit hyperactivity disorder, or ADHD for short, is a developmental disorder characterized by hyperactivity, impulsivity and difficulty paying attention and controlling behavior. ADHD is commonly associated with children but also affects people of all ages. Approximately 8 million adults have ADHD in the United States. Scientists are unsure about the precise cause of ADHD, but it is likely a combination of environmental factors and various genes that affect brain function.

Function

Acetyl L-carnitine has the ability to cross the blood-brain barrier, where it's thought to increase energy metabolism and prevent the deterioration of brain cells. For this reason, acetyl L-carnitine demonstrates a potential capacity to help treat diseases and conditions that affect cognition and behavior. Researchers have begun to study the effects of acetyl L-carnitine on Alzheimer's disease and Down syndrome, though with mixed results. If it proves beneficial, its effects are likely limited to improving the symptoms rather than treating the condition itself.

Evidence

In 2008, a group of researchers from the Università Cattolica in Rome published a study in the "American Journal of Medical Genetics" that suggests acetyl L-carnitine can reduce hyperactivity and improve social behavior in young boys with fragile X syndrome --- a genetic condition commonly associated with ADHD and autism. The boys received between 20 and 50 mg of acetyl L-carnitine per kilogram of body weight per day. This corroborates a previous study by the same authors that demonstrated similar results. Another study in a 2004 issue of the journal "Psychopharmacology" found that acetyl L-carnitine reduced impulsive behavior in adolescent rats. This holds some promise for a beneficial effect in the treatment of ADHD patients but requires further testing, especially in humans.

Intake

Acetyl L-carnitine is generally considered safe. Unlike other drugs, it's devoid of psychostimulant effects, which is why it's so appealing as part of a potential treatment plan. However, acetyl L-carnitine does exhibit mild side effects in doses of 5 g or more. These include diarrhea, increased appetite, body odor and skin rash. It may also interact with certain medication such as isotretinoin, valproic acid, doxorubicin and AZT. People with peripheral vascular disease, hypertension, alcohol-induced liver disease, diabetes and kidney disease should talk to a doctor before taking any carnitine-related supplements.