My 3 month old son just started on Nutramigen formula yesterday afternoon and I was wondering if anyone knows how long it takes before I would see a difference? He is a very colicky baby and has had a lot of difficulty with gas, fussiness, and reflux. He also tends to start screaming after drinking about an ounce of formula. Nutramigen is the 5th formula he has been put on and I am really hoping to see a difference with this one. He is also on Zantac for his reflux which has helped stop the projectile vomiting but I am hoping this formula will improve his colic.