The effects of Adderall start to work within 30 minutes. In contrast, Vyvanse takes approximately one to two hours to take effect.Forms and Dosages Adderall IR is available in tablets ranging from 5 to 30 milligrams (mg). Adderall XR is available in six different mesure ranging from 5mg to 30mg. Vyvanse is available in fourreau and chewable tablet