Blogger's note: If you are interested in taking tyrosine as a supplement for ADHD or related disorders, the above diagram is a summary of the key nutrients which interact or play a role in tyrosine metabolism. In this blogger's opinion, we want to avoid deficiencies (or, in some cases, excesses) of any of these nutrients. If you are in a rush and do not want to read this whole posting, this table may be a good starting point. I have listed a number of links at the bottom to other sites as far as recommended daily intakes are concerned for the majority of these nutrients. This list is by no means extensive, but this will hopefully highlight the major impact factors in maximizing the benefits of tyrosine supplementation as an ADHD treatment strategy.
(If the above diagram is not easily visible, most browsers will allow you to left-click the image to get a blow-up version, or you should be able to right-click the image with your mouse and view the image in a new window).
We have spent the past seven postings on the pathway of tyrosine metabolism and the implications of supplementing with this amino acid nutrient (and its derivatives for ADHD). But does it actually work?
For the last seven postings, we have been examining the following metabolic pathway of tyrosine. Included are the major enzymes and key nutrients responsible for this process to occur efficiently
Here's a brief review of the evidence for (and against) tyrosine supplementation. Much has been covered in the previous 7 blog posts, but some is new. Links to the studies (or summaries of the studies if the full article is not available) are provided in most cases.
Potential advantages of tyrosine supplementation for ADHD:
Disadvantages to tyrosine supplementation for ADHD:
As a blogger on the subject, I always try to remain neutral (many times, however, this can be extremely difficult). When researching the stories and studies on tyrosine supplementation for ADHD, the one thing that continuously caught my attention was the degree of discord between the studies on tyrosine supplementation for ADHD (most of which showed no significant improvement) and the number of clinicians who prescribed it (and individuals who reported benefits from tyrosine). Again, this disagreement may be due to a number of things (differences between study conditions and the treated individuals, co-treatment with ADHD medications, the placebo effect, immediate vs. long-term effects, etc.), so we need to be very careful when making a comparison.
Having said all of this, and weighing everything I've read and researched, I admit (as a blogger) to being skeptical about the overall effectiveness of the whole tyrosine supplementation thing for ADHD. There just don't seem to be enough positive studies grounded in long-term improvements which tyrosine. Nevertheless, the number of positive reports on tyrosine from individuals are too great to ignore in most cases, so an outright condemnation of tyrosine for ADHD is by no means warranted.
It is important to note that none of the studies I've seen (both those supporting or refuting the idea of tyrosine for ADHD) have paid much attention into controlling for the co-factors of the enzymes responsible for metabolizing tyrosine. Just as a reminder, co-factors are essentially vitamins, minerals and other nutrients which are used to help enzymes function properly (or at least more efficiently).
So if we do decide to begin a tyrosine supplementation program, we should make sure we have adequate levels of the following nutrients (I have listed the major nutrients, and where it helps in the tyrosine metabolic processes. It is important to note that this list is not 100% complete, there are several other nutrients which play a role indirectly in the process, but I am just highlighting the major ones I've come across in the studies I've seen on the metabolic pathways of tyrosine to dopamine, norepinephrine and epinephrine)
Here are some links to recommended daily levels of the following nutrients and "cofactors" which can potentially affect the outcome of tyrosine supplementation for ADHD: