I recently came across something called Feed thickeners to help babies with reflux or regurgitation issues. Apparently it can be mixed with breastmilk or formula. Anyone used it?

Yes, I have a friend gave Total Comfort formula milk to her reflux baby, through the suggestion from her baby's PD. She mixed it with breastmilk. It does help to ease the situation. Also, you can elleviate baby in an inclined position after each feed to avoid vomitting. Baby will outgrow reflux after 1 year old.