HGH releasers....

Here is the story.... I am 20 and 5' 8"... 5' 9" with shoes.... Its considered average to below average height. I never had a large growth spurt in my life.... Is it possible with the proper diet and hgh on the side with exercise and streaching to add a couple of inches to my height. I know there are plenty of cases of people past the age of 20 who gain a few inches to their height.... Plus are hgh releasers a gimmick or do they really work.... I obiovusly cannot afford getting actual hgh injections...