it is likely too late but your son would need to be carefully examined by a pediatric endocrinologist. if he has completed his growth (based on bone x-rays and other lab tests) it would be unlikely that he would grow taller.
is hgh beneficial to a youth in stage 5 tanner? . could hgh benefit a 16 yr old boy who is stage 5 tanner but has only grown 1/2 inch since the age of 12?