Amino acids are natural building blocks of protein. They can be obtained from food and some, including carnitine, can also be made in the body from other amino acids. Carnitine plays a critical role in the metabolism of fatty acids, a process whereby fats are burned for energy. This particular process can be disturbed in individuals with ADHD, leading to a buildup of toxic fatty acids.
Some experts consider carnitine deficiency to be rare because this amino acid is plentiful in food and the body can also make its own. In reality, deficiency may be far more common than believed, either because of poor diet, or because carnitine production may be inefficient in certain people.
The beneficial effect of carnitine supplementation depends on the presence of B complex vitamins, particularly vitamin B2 (riboflavin). Without enough of these vitamins carnitine is ineffective, so it makes sense that these nutrients should always be supplemented together to improve outcomes.
Carnitine supplementation has been shown to help in a variety of conditions, including ADHD, but also cardiovascular health, fatigue, and hypoglycemia.
In a recent double-blind study performed in The Netherlands, 24 boys who had previously been diagnosed with ADHD were given carnitine with no other vitamins or supplements, by mouth at a dose of 100 mg per Kg of body weight up to a limit of 4 grams a day. This is a very high dose, although non-toxic; however, a lower dose combined with B vitamins might have produced even better results.
13 of the 24 boys, slightly more than half, experienced significant improvements in home behavior as well as school behavior. Improvements that were reported included increased ability to focus as well as reduced aggressive behaviors, with the majority of boys experiencing no side effects. A result like this one would be positive for any drug seeking approval. It is important to note that carnitine achieved this by normalizing a function of the body, thus promoting better health. In contrast, drug treatments work by temporarily suppressing aberrant mental activity. Results from this study might have been even better had the carnitine been combined with a B-complex supplement. (Prostaglandins Leukot Essent Fatty Acids, 2002; 67 (1): 33-8)