hgh at a high does will do both grow new muscle tissue and make your current tissues bigger but the sides at so high of a dose make it tough to run for long and get the best result from ... i am running it at 3 ius daily and have carpal tunnel occasionally ... so i could image people who are using 20 ius daily ... you do get used to it ... but i have heard of people not being able to grasp a barbell cause of the pain ... you gotta see how you react