yeah........by 500% in some article......research it.........i take 4g with 2g alpha gpc every night......definitely grew an inch the past 4 months using it, my arms got longer also, but im 17. Definitely use it for the gh purpose. The only problem with it is like a 3 minute temporary shortness of breath everytime you use it. Its pretty annoying. But its worth it. It relaxes you and your muscles nicely. Didn't give me vivid dreams like some people say but other then that its a very useful, cheap product. Buy it at 1fast400.com