Use with caution.
Yes it works. Calm down anger/irritability also when feeling down. Warning on the increase of nervousness. (Mild hand tremor - very temporary was my clue after months of daily use - 500g). I asked my doctor, who very nice, if it might be the tyrosine. She wasn't exactly happy when she asked 'What are you taking that for?"
I took it in the eighties as a long shot for some continuing fatigue despite treatment for hypothyroidism. It didn't work so I stopped. But some reason I tried it again one month later and realized it's a 'happy pill'! It's effective quickly for me (within an hour) Again use with caution.
All amino acids I approach with caution.