Buy Adderall 30 mg online. These medications start to work in 30 minutes to two hours, Adderall starts to work in approximately 30 minutes to one hour, and the effects of Adderall typically begin to wear away after four hours. The immediate-release Adderall version will last around 4-6 hours per dose, while Adderall XR, the extended-release version, only needs to be taken each morning; Adderall is one of the most widely prescribed ADHD treatment medications.