"i took vyvanse 50mg for about 4 months. as i started the medication everything was going great and i was focused. however, i was an emotional wreck while on it. people at work thought i was going crazy because i was angry at silly things, which is not my personality at all. vyvanse seemed to work good in the mornings but wore off around 1pm. i took it around 7:30am. the medication really depends on what you eat. 12 hours is not true for me. i don&#039;t know about you but i don&#039;t have time to make sure i eat this type of food for dinner and this type for breakfast just so my my medicines will work. some days the vyvanse would not work at all and i didn&#039;t get anything done. vyvanse also caused hair loss and turned grey. i&#039;m 25 yrs old."