Our insight into the many benefits of human growth hormone continues to grow with each new study. One such area of Trusted sourceHGH and immune system Pediatric ResearchGo to sourceresearch is how HGH affects immune system functions. Because growth hormone influences cell regeneration – in other words, every cell in the body – HGH also impacts crucial immune cells. HGH does this, in part, by activating insulin growth factor 1 release in the immune system that helps to support cellular activities.