Thank you for your query on Healthcare Magic.
The predictable height of a child is already determined and it depends on the genetic condition of the family and mean parental height which is decided by both father and mother height.
Injections are advised to people with shprt stature having growth hormone deficiency
and they can't be given to people with out any deficiency or syndromic short stature.
Therefore I advise you to give an opportunity to the child to grow maximum of his attainable height by giving well balanced, nutritious diet.
Apart from good diet, no medication is required.
Monitor his height on growth charts and if it is within normal , nothing to worry.
Hope I have answered your query.