Vyvanse (lisdexamfetamine) typically takes about 90 minutes to 2 hours to start working, although some people may notice effects as early as 30 minutes. The peak effects usually occur around 3.5 to 4.5 hours after taking it. The medication is designed to last all day, with effects typically lasting 10 to 14 hours depending on factors like metabolism, dosage, and food intake. Taking Vyvanse with food, especially a heavy meal, can delay the onset by about an hour or more but does not significantly change its overall duration of action.