My 1yr old is constipated

Hi momsh ask lang any recomendation on follow on formula? Dati po kasi nung s26 gold si baby everyday sya na poop pero nung nagswitch kami to Lactum every other day na na poop si baby and nahihirapan sya maka poop. He's taking duphalac din ngayon as prescribed by his pedia pero constipated pa rin po sya