I had the same result as Cure or Bust. Did not have increased walking speed, but my legs Much stronger ie if I was on the floor, could not get up, but when taking 4-AP, my legs were strong enough to enable me to stand up.
When taking 10mg of 4-AP, I would get bad side effects, and could not tolerate that dose, so started taking 5mg every 4 hours. Now I take 4-6 x 5mg every 4 hours, every day.
4-AP is very cheap to have it compounded yourself, why bother with Ampyra - the pharmaceutical company is making a Huge profit on this drug. They treat MS as an Industry.