One is a media cell culture grade, which has about 70 percent purity, and the other is a receptor grade that has 95 percent purity. Although the receptor grade is really the drug meant for human use, it can be 10 times as expensive as the cruder form (like your price quote!). Now I'm not sure anyone has done back to back trials, but from my own research I believe the difference between the two would only be able to be noticed in a laboratory setting.
I just read the same thing. My understanding is that Receptor Grade really only makes a difference in lab settings (not that any of us could afford $2000/mg anyway) S I'm going to check out the price at $210 for media grade-that seems excellent