Johnny N. - Stop being a troll. You're whole argument is flawed - there are no studies PROVING that it works because there are NO STUDIES AT ALL ON THIS ISSUE. There are no studies PROVING THAT IT DOESNT WORK EITHER.
AT BEST you could say there is no proof that it works and until then you are skeptical but making that blanket statement shows your prejudice.
There are thousands if not hundreds of thousands of people who could say based on their experience L-Tyrosene and L-Theanine help with their depression, motivation and anxiety. Especially when taken with the co-factors needed to produce dopamine. That is evidence that it does work. Some of the evidence rules out placebo effect because many people started taking L-Tyrosene etc... For something else and only noticed the change as if it were a side effect. Can't have a placebo effect if you are not expecting an effect in the first place.
My case is similar. After joining a gym and feeling the runners high etc.. For a couple of years I was getting bored with working out and instead of loving the gym it was a painful chore to get down there. I was feeling less and less of a workout high and also seeing a total plateau in results. I talked to a few guys down there and they suggested some amino stacks to give me more energy during the workouts. One was tyrosine. Started taking it and L-Theanine along with vit-D tab. As luck would have it couldn't get to the gym. Had a bunch of crap to do around the house. Stuff you hate doing. Bills. Laundry. Tax stuff for quarterly taxes. To my amazement I jumped on this stuff and knocked it all out. It was like motivation was way increased and resistance and lethargy were far reduced. Got done with all that and would usually sit in front of the tv for the next few hours watching crap I didn't even care about or surfing the net. Instead I just felt like calling a friend and going out to dinner. All of us with SA know that we never FEEL like that doing that. Sometimes we push through and force ourselves but it's never or rarely something that we are excited about.
Next day similar thing. Feeling good. Feeling chatty. Feeling motivated. So I start looking for the reason behind the change. Instead of stacking all the amino Acids I took them one by one. L-Tyrosene and L-Theanine were the ones that caused the mood boost.
Lot of evidence that there are many different types of depression. If yours is lethargic and anhedonic (nothing seemed to matter)(no interest in fun things like sex or sports or friends) my understanding is that it's likely caused (at least in part) by a lack of dopamine. And one reason you may lack dopamine is a lack the chemical percusors to make it. L-Tyrosene and L-Theanine and Vit-D are part of that chain.
If your depression and SA are of the agitated variety - anxiety high, either feel
Threatened or aggressive or can't sleep through the night because brain won't shut off, racing thoughts. Then it is my understanding that you are probably lacking Serotonin. And maybe even overloaded with dopamine. If you have this kind of depression anxiety - what I've read is that L-Tyrosene and L-Theanine won't help and may hurt and instead you need Seratonin boosters like 5-HTP, L-Tryptophan etc.
That's what I've read. That's what I've experienced personally. Do the research for yourself. Talk to doctors and nutritionists. Cautiously test for yourself. Don't just go gobble a bunch of pills.
Bear in mind that there will never be a large double blind study to test any of this because the pharmaceutical companies have no way to patent naturally occurring substances and thus no way to make money off of them. The LAST thing they want is to prove that some cheep over the counter supplement works as well or better than their $200 bottle of pills.