Your body can only convert about 200 mg of Vyvanse at the most at one time(I am precribed Vyvanse 70mg) , because it "the Vyvanse " has to bind with lysine in the small intestines and you have only a certain amount available in a certain peroid of time before it is depleted temararily (lysine is an essential amino acid made by the body) and ususing too much at one time will result in un"activated" Vyvanse which will simply pass through the intestines and into the colon and then out of the body,so it is best to space 240mg into 120mg or a bit more and save the rest for the following day when the lysine in the small instestines is back at normal levels...2 to 2 and 1/2 70mg capsules of Vyvanse or the powder inside witout the capsule is about the maximum you can take without wasting any of the Vyvanse which will simply pass through you at higher dosages unactivated and exit your body inconverted into the active dextroamphetamine and all that so,taking more than 2- 70mg Vyvanse is gonna waste everything more than that unless it is taken the next day or something..the Vyvanse is "activated" into dextroamphetamine by lysine in the small intestines!! even though Vyvanse contains a lysine deriivitive in the capsule /powder along with dextroamphetamine in an unactive form it must be bound chemically in the small intestine with the lysine there...