How much can hgh make my daughter grow? (bone age 15), she is 13 currently. her endocrinologist says it is pretty much useless. is that true?

Bone age: With more advanced bone age there is less chance to grow taller with growth hormone as there are changes in the bones that preclude more growth in length . At any rate we need to do multiple studies to decide for a trial of HGH although it seems to be less likely useful in your daughter

Likely: Bone age is determined by examining the growth centers in the wrist/hand/etc. against population standards. If a kid is HGH deficient, the BA should be younger than actual age. If older, the kid is not deficient and adding extra HGH might finish growth sooner at the expected height. It does not add anything. Most women finish linear growth at 16-17 so her growth centers are starting to close