I started taking liquid amino acids a few weeks ago. So far, I'm very impressed with the results. I have more energy, I have better mood and my joint pain has reduced. I'm still not sure if I'm experiencing some kind of placebo effect but I don't think so. I doubt that I would have seen so many improvements if that were the case.
I think I really had some amino acid deficiencies and I plan on supplementing with liquid amino acids from now on.