I tried GTP enth for four weeks. 3 of 4 injections were very painful, and yes I did use new pins. I also got sick for a day or two after every shot. The test flu bad, missed work two days. I have two other friends that took it and one had no problems and the other had the same exact problem I had. It reacts with everyone different. I had to stop after 4 weeks because it was doing more harm than good. I switched to QV enth and love it. It is pain-free for me but painful for my buddy, everyone is different. I would suggest trying 1cc the first week just to see if it affects your health and then take it from there. Also, cutting it with another item can reduce the pain. Good luck, send me a private message and let me know how it turns out.