Thanks Annesse,

QUOTE: "Phenylalanine breaks down into tyrosine, tyrosine breaks down into dopamine and dopamine breaks down into adrenaline and noradrenaline."

I'd like to correct a slight error in terminology so as to avoid possible confusion and more importantly, the potential for health effects should anyone choose to supplement any of these amino acids (some are available in isolated form in health food stores).

Phenylalanine is a 'precursor' to tyrosine which in turn is a precursor to dopamine, as well as a component of other neurotransmitters.

NOTE: Supplementing amino acids in isolation is a form of nutritional pharmacology and as with other pharmacological approaches, it is advisable to research 'uses, side effects, contra-indications, interactions with other medications and the potential health risks' before doing so.
There is ample information on the internet with respect to each amino acid along with these factors as well as providing descriptions with respect to their effects on body functions.

With love, Erika