Is L-tyrosine safe for young adult?

I'm 20 y/o,I had a mild depression but I didn't want to take pills from the doctor so I went online and looked for a natural alternative. I heard that L-tyrosine is good for depression and mood so I bought a powder from health-store and took 500mg of L-tyrosine the first day and 300mg of L-tyrosine the next day. I did feel better but is it safe and can it be used long-term or is it for short-term only? Thanks.