I think 20 was good to start, we'll see how 30 goes. I would say dose will be dependent on user (size, cycle history) and brand. I've read feedback where 1 brand was gtg at 10 but others needed 30-40....mine is super powers from flex....it'll also depend on your goals. I was just kinda going for recomp, literally didn't change my diet and 20 mg was fine. Also, it'll depend on cycle length and what you're stacking it with but I'm general I would say 20 is a good place to start.....I saw once that msten has a shelf life of 6 months but I could be way off on that. It'll pry depend on how it's stored.