Im definstely no expert, but what happened with my dd is at around 4kg when she first started on it the gp prescribed .5ml twice a day which basically did nothing, upped it to .8ml twice a day and it worked like a charm. Every 1-2kg of weight gain we were upping it, until around 8kgs she was put on 2ml twice a day which has remained a good dose. She is 10kgs now...tried to wean off it recently with a big fail, so its definitely effective. I also found it took a day or so to notice it working after starting or upping a dose