There is no way to predict how long Guillain-Barré syndrome will last. The symptoms usually reach their peak by about the third week of the disorder. The symptoms can remain at that level for days, weeks or months, and then gradually get better. Strength slowly returns. It may take only several weeks or as long as three years. Most people recover completely within a few months, but some never regain full strength and may require surgery, physical therapy or orthopedic appliances to correct problems or train the body to adapt.