One of the most common questions asked about HGH is whether it can make users grow taller. Between the ages of about 12 and 18, your body is still growing. During this time, the administration of HGH can help you add inches to your height. As such, HGH is an essential part of therapy for children who have growth disorders such as dwarfism. However, between 18 and 21 years old, growth plates on your bones fuse together and essentially “lock” your height. Administering HGH may cause individual bones in your body to thicken, but it will not lengthen them.