My baby is 3 months and has reflux. took him to the dr and the dr said i can try a lil cereal to see…

My baby is 3 months and has reflux. took him to the dr and the dr said i can try a lil cereal to see if it helps keep the milk down. well im not ready to feed him cereal or baby food just yet...doing research and i read somewhere that i could thicken my breast milk by using Gelmix. says that it helps with reflux. has anyone used this or another thickener? how did it work?