It hurts like a motherfucker. Not trying to sound like a tough guy but I have a pretty high tolerance for pain and yeah this killed me! I shot it in my quads and literally was limping and could barely walk for a week. Got to the point where the swelling turned red, then dark red and then almost a black. When I couldnt get in my SUV I decided I had to go to the ER and they took care of it. Lesson learned...Ill never shoot winny again, only oral winny from now on. The thing is ive used zambons in the past with zero problems. I guess I just reacted to ANC Pharma pretty bad.