In my experience, GP has been really really inconsistent. I think years ago they were much more legit, nowadays I wonder how much if any hormone is in any of the vials. I'm hearing more and more about Uncle Z being underdosed, at least their test. That said, I would trust them more than GP by a longshot, you might just up your dose to account for it.
TBH my best results have all been locally obtained gear. My faith in online is waning.