Hey Cris, Wow Guam! We use ST http://www.simplythick.com. They have a starter kit so you can play with the thickness you want. It’s is just emtpy calories , i think zanthum gum and it slids through them, helps them poop better too. Also, we thicken with oatmeal. Just a scoop in a couple bottles at first, then gradually work up to a few scoops in each bottle. That seems to be helping move things along too. Some babies can tolerate the rice cereal, but many get constipated and have horrible gas. Can the doc. there give you any samples? Some of the other thickeners are corn startched based and cause major gas too. Hope this helps! Worked for us and help with her reflux alot! Saralh