In studies of Alzheimer's disease, subjects were treated with 1000 mg of oral thiamine hydrochloride three times a day for 2 to 12 months without any reports of adverse effects [7,25,26]. In a separate experiment, subjects were titrated up to 8000 mg per day over a 1-year period. The only side effects reported were nausea and indigestion in 2 subjects when they reached 7000 and 7500 mg per day . There have been several clinical trials of thiamine derivatives for a variety of disorders that used doses between 300 and 900 mg per day in divided doses for periods up to 3 months. No side effects were reported in these studies [2,27-29].