that's a good amount of time to see if anything has happened. my stone is 2.5 cm. so far i have done the gold coin 4 weeks and now the chanca piedra for 2 weeks. and every day i take 1400 mg malic acid. before that i used the same supplements but only took it once day, i had to learn that you have to do it more times a day. the malic acid i have been doing for about 3 months. i saw my md last week and he thought we should do an ultrasound in 6 months. he is curious too. so i hope it works for you, so i have a chance too. i am certainly planning to keep going. good luck, johanna