If you want proof ATHLEAN-X works just follow a few of Jeff’s videos on YouTube. He backs everything he has to say with science which is what I love. I went through AX-1 and added some T.N.T. workouts and got amazing gains. I was always a skinny kid but now with ATHLEAN-X  my arms are starting to pop through my shirts. The six pack promise works great as well, I shredded fat and was able to develop a 6 pack that I never had before.  THANKS TEAM ATHLEAN.