I have not used the gray tops but I can tell you that I have found better results using Hyge than when I have used blue tops. I can't feel a differene while using them but I have seen better results using higher quality GH. I'm sure the gray tops are not bad though. You could always get a small amount and get some blood work done to test your levels and see how they compare to your Hyges. Honestly though, I think Hyge is a great product and if I had my choice, I woud prefer to go with them, even if that means using a little less than I could afford to use of generics