Hi Dragonfly, if you do want to give him formula there is a really good one available which we use called Bellamys. It comes in stage 1, 2 and 3 and is organic and non GMO. We now mix it with the organic cows milk as we are weaning my DS onto cows milk. It's available from any good supermarket (both Safeway and Coles), its in a white tin with a blue lid. We had problems with other brands but this has been a winner for us and so far we've not had any probs getting the amount of formaula down and regular milk up. We are now up to 150mls of formula topped up to 250 with the organic cows milk, so far so good. I've taken it really slowly though as I din't want my boy to reject the milk, soon we will be all cows milk and the formula will be gone yay!!