Supplementing tyrosine was an experiment in increasing my thyroid function. Most of the supplementation i tried before then, specific to T4 synthesis and the T4-T3 conversion pathways, had been very helpful -- each producing perceptible results. Tyrosine supplementation increased energy, all right, but not in a positive fashion; i felt uncomfortably "wired" and the minor "essential tremor" i experience when overstimulated became almost chronic. From my study, i figured that one of a couple of things might be going on -- either pushing myself into periodic hypERthyroidism, or (more likely) increasing my levels of adrenalin.
I discontinued the tyrosine i was taking (500mg to 1000 per day, either all at once or split dose), and started using mucuna (mucuna pruriens, marketed with the label Dopa Mucuna). The tremor faded away to almost nothing, and my mood (equanimity) improved. Desiring more energy on some days, i've been experimenting with tyrosine again. One 500mg capsule taken every other day seems to give me a little boost without too much agitation -- but again, if something gets me riled up back comes the tremor. :-(
(How i wish they were caplets, so i could cut the suckers in half, and take one of THOSE every other day! It will be a messy job halving those damned capsules.)
WARNING: entering the realm of conjecture! :-) Reading up on dopamine has given me some interesting insights on my life. It would take a novel-length post to explain it all, so i'll give you the short version -- i strongly suspect myself of being short on the stuff all my days! And looking at what happens to me when i supplement tyrosine, i think i see what could be happening.
For some reason, tyrosine seems to take a shortcut to adrenalin in my body -- it doesn't seem to hang around the levodopa step. This may happen because of my "weak thyroid" and be self-perpetuating, i don't know. Because my thyroid doesn't use enough tyrosine to make a robust supply of hormone, then more tyrosine is available to go the other route and my body compensates for the low energy with adrenalin? GOK.
...back to my reading....