Hi yuukalim0404, I solely breast fed my daughter up to around 5months until I made the decision to move her onto formula. Every child is different, but for me, it was a very hard transition, and found it difficult to obtain help (as breast feeding is so strongly supported). Anyway, as I said every child is different, so it is a matter of finding the best formula to suit your childs needs. After around a month of rejection from my daughter, what worked for me was going back to basics. I started with making sure my daughter would take BM from a bottle again (which she did, this way I made sure a bottle wasn't the issue). Then, I did 10% formula, and 90% breast milk one day, next day 20%/80%, 30/70 next and so on. As I said, I had major issues hence why I started with small ration movements, most do 25/75, 50/50, then 25/75. It was draining, as I found myself having to express for each feed (which I wasn't used to). Regarding formula, I was in Australia when we made the transition, and used Nestle Nan HA. It was recommended by Health professionals as it tasted the closest to BM (I had tried many others previously, which she just refused). It worked perfectly. It is sold here, but when we moved here, the HK version (made in Germany) ended up giving her a very runny nappy. So, we went to the Paed. and she advised they recommend three brands, Enfamil (or Enfapro for 6mth +), Cow and Gate, or S26. We are on Enfapro, and it works fine for my daughter. However some had advised that it caused constipation for their child. I think it will be a matter of trial and error, but if you do go to the doctors anytime prior to making the transition it would be beneficial to ask. I hope I haven't confused you, but do hope it helps. Any further queries please don't hesitate to let me know.