Tyrosine

Tyrosine, an amino acid, is a precursor to the neurotransmitter dopamine. It is converted to L-DOPA by the enzyme tyrosine hydroxylase.

It is also a precursor to the thyroid hormones triiodothyronine (T3) and thyroxine (T4)

Tyrosine and its precursor phenylalanine are required for the synthesis of coenzyme Q10

ME/CFS
Reduced levels of plasma tyrosine have been found in ME/CFS patients.