Human growth hormone (HGH)
travels through the blood and stimulates
the liver to produce a protein called
insulin-like growth factor #1(IGF-1).
IGF-1 helps the cartilage cells located
at the ends of long bones called the
growth plates to multiply, which is
where bone growth occurs. During puberty
age, this leads to growth in the length
of the bones and increases one's overall
height.