In regards to amino acids:

It is best to take them on an empty stomach. They are often slow to show benefits. But after 2-3 months if you notice nothing different, then, there is no reason to continue.
They often compete with each other so spacing them may help if you only take 2 or 3 kinds.

I used to take taurine for my gall bladder and it did work to improve bile flow. I was only using 500mg a day, but when I upped to 1000mg a day, after reading the new information, that is when I noticed the tinnitus improving. That took a week or so.
It is also improving blood flow to my feet, which are not as cold as they once were.

The glutamine is new for me. I am trying this at 1000mg a day to see what it can do for my recent severe heartburn. This is working out really well too... so I am pleased with that, and not needing to use RX drugs for it. It took just over a week to reduce my heartburn, and now I don't even think about it anymore!

So non response may be due to low dosing, as well. It is recommended to not go above 3000mg a day of taurine. Bodybuilders use alot of glutamine for muscle fatigue. I wouldn't recommend their high gram doses for the average person.