Tyrosine is a non-essential amino acid (it can be synthesized within the
body) that is a precursor for epinephrine and norepinephrine.  If a
person were depressed due to a shortage of epinephrine, then tyrosine
might help, but it should have no ill effect if there is no shortage,
i.e., it is not acting like prescription antidepressants which block
enzymes to increase neurotransmitter levels, which potentially can
result in too much of a neurotransmitter being present in the brain.

Ed Friedman

The risk is the tanning.