The invention involves various embodiments of a method for treating a human being for a condition associated with (1) a clinical state of impairment of carnitine or carnitine esters, or decreased fatty acid metabolism, (2) low energy production or lower ATP production, (3) clinical hyperammonemia, and (4) clinically high pyruvate levels resulting from a deficiency in the biosynthesis of carnitine. The method involves administering a therapeutically effective salt of N-6-trimethyl-L-lysine.