If I am taking Fuoxetine, may I take the supplements L-Phenylalanine and L-Theanine? Thank you?

If fluoxetine and mirtazapine/remeron are the only prescription meds you take, then yes it should be completely safe to take phenylalanine and l-theanine. While it isn't going to harm you, you may not necessarily like effects of the combo of these 4 things. I've mixed these (and other amino acid suppliments) with similar antidepressants in the past without any problems or undesirable effects. Some people don't notice any effects from l-theanine or dopamine precursors like phenylalanine or tyrosine. I'd recommend that you do a little research (amazon.com is one way to compare reviews of different brands) and make sure you buy from the most reputable manufacturers possible. Some people would say you're just throwing your money away... I personally think the right supplements for the right reasons can be useful. But they're never cheap. Never ever mix 5HTP,St.Johns Wort or Sam-E with those 2 psych meds.
-sweaty