Human growth hormone (HGH) is a vital hormone produced in the pituitary gland that stimulates growth, cell reproduction and regeneration. As we get older, HGH levels naturally decline, sometimes leading to undesirable effects. HGH injections can help combat things like loss of muscle mass, increased body fat, reduced bone density, lacklustre skin and hair, and reduced energy levels. They essentially act as a "fountain of youth" for aging adults who want to maintain a youthful vitality.