Human growth hormones (HGH) are important. These hormones are responsible for keeping the body youthful and strong. They are naturally occurring. HGH is produced and secreted by the pituitary gland in the brain. The level of the hormone is high when a person is young. It is at highest during adolescence. However, every 10 years, the level of HGH in the body declines by as much as 15%. Thus, people aged 30 years and above start to realize and experience the inevitable process of aging.