I have twin babies, born at 34 weeks, 1.4kg and 2.1kg but they have added good weight as of now I was giving breast feeding suddenly they rejected it and liked the formula I have tried everything but they won't take breast feed, so I started giving lactogen because nan pro 1 which I was giving before is so costly so I had to buy lactogen because they have huge appetite they finish one packet of milk in two days, so I had to switch to lactogen 1 please is lactogen okay to give?? Because they are twin they are 5 and half months now..