A double-blind placebo-controlled trial of L-threonine in amyotrophic lateral sclerosis.

Fifteen patients with the unequivocal diagnosis of amyotrophic lateral sclerosis (ALS) completed a 1-year randomized double-blind placebo-controlled trial of L-threonine (2 g daily). During the study, patients in the placebo group showed a decline in functional status consistent with the natural history of ALS, which was not statistically different from outcome in the patients in the L-threonine group.