I was put on Metformin because I was having periods where my cycles were completely irregular and in October 2011, I bled for 3 weeks. I went to the ob/gyn and she told me I was insulin resistant and I wasn't ovulating correctly so that's why my bf and I weren't able to conceive. At first, I was only on 1000mg a day and it made me bleed randomly again, so I was put on 2000mg a day and it really began working when I got my period in November on the 28th, ending around December 4/5. My bf and I were having sex everyday and I'm pretty sure I felt myself ovulate in the middle of December at some point. On the 28th of December, I was about 3 days late because I was back to a 28 day cycle and bam! I was told I was pregnant when I went to the doctor for a regular checkup. Now, I'm almost 5 months pregnant! Metformin works for a lot of people and definitely worked for me! Some people with PCOS have a tougher time though so try Clomid with it as well.