MAM 6oz Feel Good Pure Glass Anti-Colic Wide Neck Baby Bottle, Slow Flow Skin Soft Silicone Nipple, Easy to Clean, BPA Free, 0+ Mths, Easy Switch Between Breast & Bottle, Made in Europe, 3 Pk, Unisex

I use the MAM glass bottles! We love them, how old is your LO? Could the nipple size be too big or small? https://a.co/d/05mEw0KL For formula, we use Aussie Bubs organic whole milk & our little one loves it, no issues Hope this helps!