Get Adderall XR Online Overnight at affordable prices. Adderall and Adderall XR (amphetamine and dextroamphetamine): Adderall begins to work in around 30 minutes to 60 minutes. The impacts of Adderall normally start to erode following four hours. Adderall XR keeps going around 12 hours. What does Adderall XR do? Adderall XR comes in the market as the best stimulant for the treatment of ADHD. However, its surviving state is an extended-release formulation that gradually begins its mechanism, but its properties survive for 12 hours. Therefore, it is recommendable to use on an around-the-clock treatment. One more state of this medication, i.e., immediate-release formulation, but its properties remain in the body for around 6 hours. To know which variant will be suitable for you to meet your doctor.