B12 is one of your B vitamins and will be in the B Complex along with B1, B2, B3, B5, B6, B12. The B vitamins are considered the stress vitamins and one of their jobs is to help your nervous system though if you do research you will find that each if the B vitamins have many specific jobs in the body. L- Tyrosine is an amino acid.L-Tyrosine is converted into dopamine and norepinephrine. Alternative practitioners recommend it as an anti depressant and for anxiety. L-Tyrosine needs to be taken on an empty stomach while the B complex should be taken with food. The L in front of the Tyrosine means that it is a natural form of tyrosine. Hope this helps.