Adderall= Amphetmine Salt mix of d-amphetamin & l-amphetamine
Vyvanse= lisdexamfetamine dimesylate
The l-isomer is what people usually complain about that causes anxiety, jitters, etc…..it’s more “body related” whearas the d-isomer ie dextroamphetamine is more “brain felt”
Each affects different activity of dopaminergic neurons.
I did some research one time that says, another reason they also add l-amphetamine to the salt mixture so that people who abuse it end up with nasty side effects.