Just to define the terms:

"Onset: When a medication first begins to work and exerts a therapeutic effect."

"Duration: The length of time that a medication is producing its desired therapeutic effect."

Source: https://wtcs.pressbooks.pub/pharmacology/chapter/1-glossary/

For me, I take 70mg daily. The onset of action is about 45-60 minutes, on average, depending on whether I've slept well, if I've taken it with protein, etc. It seems to work better if I dissolve the contents in water, rather than take the capsule intact.

Duration - It's harder to gauge this, as you shouldn't be basing it on "feelings". But I'd say for me, on average, it's 5-7 hours (it's therapeutic effect on my ADHD symptoms).