everafter, initially we give my boy similac step 1, but then after he drink it, he had serious colic problem... and reject the formulae milk. Rather go on hunger strike then drinking it. So next day, hubby went to buy NAN HA1, ( cos young time hubby takes NAN 1) and HA is the hypoallergernic milk, help to prevent allergies. Make for my boy, he drinks already less colicky and appetite getting better. So from there we continue to NAN HA2 and now NAN 3.