Dont waste your money on them. Im in a similar situation as you. Been off the stuff since November at this point. Lost track of the exact # of days.
Im in my 30's also and healthy for what its worth. Have tried a whole array of suppliments and 'nootropics'. Piracetam, hup a, l-theanine , b vitamins etc.
They are all a scam. None of them can actually recreate what amphetamine / stimulants are capable of / make you feel.
Good ol fashioned caffeine is your best bet.
I would not recommened you waste your money on these things (very expensive). If they worked so well they would be mainstream, not just marketed to niche message boards / the internet.