At what age do human head stop growing?and how does head grow at puberty?is it hgh?besides genetics what determines the size of the head?

Head growth: Substantial involvement of genetic factors in the determination of head-size is a fact. The age that your head stops growing can fluctuate. Typically, growth of head & brain is done at 21. Some HGH effects in adult bones: Generalized expansion of the skull at the suture lines brow protrusion, often with “eye popping”, pronounced llower jaw protrusion with teeth gapping. (Remember Arnold?)