It’s not that (generic) Adderall is different so much as there seems to have been an explosion of generic manufacturers all using wildly different amounts of the actual amphetamine salts and binding agents.
For me personally, the Mallinckrodt generic seems to use a different binding agent that causes bloating and occasional headaches.
The shortage has really demonstrated just how differently these generics are formulated.
Eg: I used to take Sandoz 20mg tablets that were about the size of two baby aspirins. At one point, a few months back, I was forced to modify my prescription so it could be filled as 10mg tablets.
My new 10mg bottle was filled with Teva manufactured pills that each were roughly the size of 2.5 of my old Sandoz 20mgs - despite being half the dosage. That’s a ton of filler.
The worst part about the shortage - beyond the anxious pharmacy hunt each month - is that my insurance pushed a new shortage policy that places a moratorium on modifying ADHD prescriptions. I literally am not allowed to try “creative” solutions like Dexedrine or even something like modafanil.