Before revision: Tyrosine is the precursor to L-DOPA, dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline) .
After revision: Tyrosine is the precursor to L-DOPA, dopamine, norepinephrine (noradrenaline), , and the thyroid hormone thyroxine epinephrine (adrenaline) .