d-phenylalanine can raise blood pressure, so this should be monitored.

I'd suggest l-typtophan instead.

Also if you feel depressed, I'd get your Vitamin D tested.
Low D is connected to depression. I haven't needed my SAD light visor since upping mine to 5000IU daily this winter. (I don't take it on days I am outside alot).

Also useful for depression is methylfolate (folic acid). There is even an RX version called Deplin:
http://www.deplin.com/HealthcareProfessionals,Trials

Folate may be too energizing however, for some people.

Another thing that works well for depression is DHA (part of the oil in fish oil). There are vegetarian versions of DHA too.
One is called Expecta, and can be found in most vitamin sections in larger stores.

SAMe is the most commonly used supplement for mood improvement. However, it may be too energizing for bipolar patients, so if you try it, start low at 200mg a day and increase very slowly.

I'd try the tried and true proven interventions before considering the weird ones like HGH or d-phenylalanine!