Disclosed herein are methods to treat cognition disorders, particularly those associated with aging. The method comprises administering a combination of a carnitine and an oxidant. Preferably the oxidant is thioctic acid. Preferably 0.12 grams to 3 grams of carnitine (particularly ALC) and 0.12 and 1.5 grams of R-.alpha.-lipoic acid are administered. Optionally, coenzyme Q and/or creatine also are administered. Preferably 10 mg to 500 mg/day of coenzyme Q10 and 1 to 30 grams/day of creatine are administered. The same method can be used to treat cognition deficits associated with carbon monoxide poisoning, mild traumatic brain injury, Type 2 diabetes mellitus, obsessive-compulsive disorder, environmental toxin exposure, and other conditions.