When I started on the probiotics I'm using I felt something the following day. how long does it take? In my opinion if you don't feel anything major after a week then the stuff is next to useless.
Immediately the probiotics should go to war and you ill feel that. There is no way you will restore the balance in your gut without feeling it.
Try to find Genestra Brand HMF products
Human strain.. works effeciently for me.. I've tried many others, none of them worked
And people say powder ain't as good as capsule but mine is a powder and it works like a charm.