If you decided to supplement with artificial milk, you have a lot of options - and it can be overwhelming. Unless your child has some kind of allergy that requires a specific type of formula - most formula is pretty similar in ingredients. I would suggest starting with the Member's Choice or Kirkland brands - which are basically the same as Similac, etc. If you want something with cleaner ingredients, there are plenty of organic and non-GMO options. Holle Formula and HiPP are the two that I would suggest looking into first. Baby's Only is also very popular.