I have been reading that formula-fed babies are more likely to be constipated that breastfed babies. Is that true?

My son is formula fed, and he had terrible constipation when he was about 3 months old. It was so heart breaking to see him cry a little each time he was trying to poop and that would come out in little hard balls each time. What I did was to mixed little gripe water in his milk and seemed to help. Gradually overtime, he started to poop regularly afterwards.