Anak, yan talaga ang challenging part ng early days! The best way to know kung hiyang or hindi ang formula ay i-observe mo ang baby's poop, if it's consistent, not too hard or too loose, then okay na usually; also check kung peaceful ang sleep niya, walang excessive fussiness or colic, at kumakain ng maayos. A few of us mums tried different brands because ang hiyang sa isa ay hindi hiyang sa iba, kaya marami ding trial and error talaga, pero if your baby has severe diarrhea, constipation, rashes, or hindi kumikita ng timbang, better to check with your pediatrician na right away dahil pwede naman na may allergy or sensitivity.