Which would be more recommended, adderall (dextroamphetamine and racemic amphetamine) xr 20 mg once a day or adderall (dextroamphetamine and racemic amphetamine) ir 20 mg 2x a day? any difference in side effects or effectiveness?

Depends ??: All are same as generic , cheap , less side effects with generic and no xr or ir only plain old simple( Adderall (dextroamphetamine and racemic amphetamine) ) . Save your money , avoid all the extras . Xr you are on a ride all day , unjustifiable prices ?

Depends on situation: There are a lot of factors that would need to be considered including lifestyle, capacity to readminister a medication throughout the day given the schedule, need for alertness at the very beginning of the day, frequency of the experience of insomnia, and sensitivity to appetite suppression. Also, it should be noted that Adderall (dextroamphetamine and racemic amphetamine) 20 mg twice a day would be twice as many milligrams of adderall (dextroamphetamine and racemic amphetamine).