Scientists have worked for the past few decades to determine if and how height increase can occur during adulthood. Though there are probably many things that have not been discovered as yet, there are studies that prove that persons can grow after they have passed adolescence. The substance that makes this possible is the Human Growth Hormone (HGH). HGH is importantly linked to a person’s growth or the lack thereof. In excess it can cause gigantism but, when deficient it can lead to short stature or failure to grow properly. Therefore, we can see that this substance and its balance are rather essential to produce optimum height. Studies have shown that by manipulating the release of HGH in the body, persons can grow taller.