It is Growth Hormone, so think of when you went through puberty. You started to develop muscles and had great energy and felt good. If you were an athletic kid or had friends who were you can remember at 13 or so you had no body fat and a little 6pack and muscles started to show. GH will give your body the ability to produce new cells, strengthen ligaments and tissue. The claim that HGH will cause your bones to grow (make you taller) only applies to those who's growth plates have not fused yet. (anyone under 18) Once your growth plates fuse, it is not possible for bones to grow longer! they will however get denser with use of GH. All of this will come with continued long time use of HGH. Yes it can speed up cancer cell production since it does help make cells. If you didn't already know this everyone has "cancer cells" in their body. Just bad cells. However you are not diagnosed with cancer till the cell count reaches a certain number. Im not sure what that number is but I am sure you can google it. So if you have had cancer then I would stay away! if you are healthy and basically have a good reason to take HGH at your age then you need to figure out if its for you. Its not something to take for size and strength it just wont get you to that level. If you have ligament problems holding you back and you had cortisone shots and this is a step you want to take before surgery then weigh it out. Remember that its EVERY morning you are going to wake up a little earlier just to run to fridge take out your measurement and inject your stomach. You then need to wait about hour and half before eating any carbs since it converts your IGF-1 levels. Its also expensive! It depends upon your goals and your commitment. Just remember that there are sides and consequences with everything you put into your body. HGH can increase organ size, give you diabetes, make things grow bla bla bla. do your research make sure you know what your doing, how and when to inject, also have bloods drawn before during and after (liver function, kidney function, thyroid, IGF-1 levels) When you come off it, make sure you do the right things to help your own pituitary gland get back to its normal function like STEVESMI said. If you are going to do it just be smart and as safe as you can. I would't take it at your age, but to each his own and maybe you have a specific reason you looked at HGH. I know this was all over the place so if you have any more questions or want me to try and make sense just let me know.