Hey all,

I know that for dexedrine, 2x5mg IR tablet is a lot more effective than a single 10mg IR tablet. I was wondering of adderall, Is there a noticeable difference between 2x10mg tablet of IR to a 20mg tablet of IR?

The difference you notice (all else like food intake, sleep, and manufacturer being equal) is probably due to the increased surface area exposure when the dose is taken in two smaller pills.

It's the same reason that chewing one's pills is frowned upon - the smaller bits they are in, the stronger the initial impact of the drug is, because it's digested faster, and the whole impact of the dose is felt at once. Even with IR (instant release), the release is not actually instant, but measured over the time it takes for your system to dissolve and metabolize the pill(s). That time depends in part on what form the dose is in when it's swallowed - one big pill is going to dissolve more slowly than two or more pieces.