Actually, after starting CrossFit, my body was screaming for protein so I did research and there are paleo protein powders with no additives, no sugar, no artificial sweeteners- just protein.
One company makes an all natural Paleo protein (name withheld as I will not promote) with beef and egg protein isolates- gluten free as well and tastes good but again, this is just my opinion. Now it does not adhere to a strict paleo diet nor are these powders regulated by the FDA but it is the closest supplement I discovered. As another individual poster mentioned, sleep is critical as HGH is supposedly released during sleep cycles(need to research yourself on this).
Also, I did an internship in college working with elite professional athletes and according to the coaches, the one hour window after a workout is critical to get protein and sugar(fruits) into the body. Because of the slow digestion of chicken, beef, eggs, it was apparent that shakes were best but they were not paleo protein shakes.
Again, I am not an expert and only recommend paleo lifestyle but if muscle building is goal, need to find an alternative that falls within guidelines. My body tells me what I need now that I understand how to listen to it.