I have hard to believe that tyrosine wouldn’t work at all, and the effect I have bin experiencing would be nothing but placebo (even though I relays it’s possible), in a way its comparable with L-tryptofan witch has proven to be effect in raiseing serotonin levels. However it’s harder to effect dopamine levels through food and supplements than it is to effect serotonin.
I think that the enzyme that converts tyrosine to L-dopa (called tyrosine hydroxylase) is normally saturated under normal physiological conditions.
I find this very interesting maybe that’s why some people experience no effect what so ever on tyrosine (in that case sudden the excess tyrosine be expelled trough the urine?), and perhaps others by nature have higher capacity of converting tyrosine in to L-dopa and therefore experience positive effects from their tyrosine supplements; until they reach as certain optimal dose. Maybe even Parkinson is associated with low levels of tyrosine hydroxylase, and by consequence high levels of tyrosine in the urine.
The effect from tyrosine might partly be associated with its ability to compete with L-tryptofan as well, serotonin moderate the effect from dopamine. orthomolecular might have a point saying that the dopameragic system must be balanced with the serotoneragic system. However I wonder what the long term consequences of elevation of eather serotonin or dopamine, on behalf of the other on, might be might be.
Personally I get at profound effect from tyrosine in combination with exercise it declines my need for sleep significantly, some times to les than 6h, I don’t like sleeping that much so I consider that as a good thing. And in general I can work a lot harder and get more out of my day. It also increases my libido. When I take it I get a that typical feeling of reward, typical for dopamine release, more often. Throw my experience high dopamine levels work very well in combination with GABA, when I was taking tyrosine by it self I almost felt uneasy some times and my systolic blood pressure was elevated by 8% (I can be sure of cores) so I started supplement with L-theanin and taurine as well. I also take a farley large dos of coca, as krillin mentioned I believe its true that the need for nero protective antioxidants increases coca as well as bluberys contains excellent ones. and of course taurine helps the natural production of melatonin as well.
Edited by narcissistic, 04 May 2007 - 02:53 PM.