worked instantly for me and i ordered it twice because it was so efficient, however my body right now has become used to it to the point where even if i brew a cup of really strong tea (seep long time in less hot water), it no longer affects my body/bowels. so I would say that in the short term it is extremely efficient, but by the time I finished my first box my digestive system was already accustomed to it and it no longer worked for me.