There is probably no other area that has people more confused in regards to amino acid therapy than the testing used to determine a person’s unique amino acid needs. There are many tests out there claiming to test your “neurotransmitter levels” via a urine or blood test. We have run samples with many of these labs. We have found that almost all of them are inaccurate and/or are misleading with their interpretation of the test results.

Before we discuss how to properly assess one’s amino acid needs through testing, I want to summarize what “neurotransmitter testing” is not. (8-10)

• Urinary neurotransmitter levels are NOT indicative of neurotransmitter levels in the central nervous system. Said differently, urinary neurotransmitter testing can NOT be used to test the levels of neurotransmitters present in the brain.
• Urinary neurotransmitter testing can NOT be used to determine neurotransmitter imbalances in the brain.
• Urinary neurotransmitter levels are NOT clinically useful if a person is not taking balanced amino acid precursors for at least one week prior to testing.
• Neurotransmitter testing can NOT be used as a method to determine amino acid needs before starting amino acid therapy.
• There are NOT many laboratories in the United States that have provided consistent, reproducible results in our clinical practice. In fact, we have only found one.

Much of the confusion about neurotransmitter testing is propagated by labs that ‘sell’ neurotransmitter testing as a way to sell products. Unfortunately, this kind of slick marketing is sold to doctors and other health care providers who then ‘market’ these false ideas, inadvertently leading to more confusion and misunderstanding.

However, even amidst all the confusion and misinformation, urinary testing, properly used and interpreted, can be incredibly insightful to help guide the proper use of amino acid therapy.

What’s “Neurotransmitter Testing” Mean Anyway?

I believe the confusion begins with the very name “neurotransmitter testing.” Almost any lab can get set up to measure urinary neurotransmitters (also called monoamines). The issue is that the results of most urinary neurotransmitter tests are not actionable, which means they aren’t useful to help direct amino acid therapy.

This is because measuring neurotransmitters in the urine does not provide any useful data unless (a) a person is taking a recommended dose of amino acids for a sufficient amount of time and (b) the results are interpreted by a practitioner trained in the proper use of amino acid therapy and laboratory assessment. Just because you can measure something doesn’t mean it is useful.

We will discuss the reasons for these two requirements here. The latter criteria (proper training) is probably the most important from a clinical perspective, because it takes proper training to understand lab results. Unfortunately, few practitioners have been properly trained in the proper use and interpretation of amino acid therapy. To my knowledge there is only one organization, NeuroResearch, which provides the training necessary to properly utilize amino acids and urinary testing to manage the neurotransmitter imbalances that are the underlying cause of many disorders and diseases. If you are working with a health care provider using amino acid therapy, be sure they were trained at one of NeuroResearch’ s programs.

As for the first criteria (taking a recommended dose of amino acids for a sufficient period of time), there is much confusion. Urinary neurotransmitters exist in one of two states.  The “endogenous” state is the normal day-to-day state that occurs when a person is not taking any amino acids. The “competitive inhibition state” occurs when significant amounts of both serotonin and dopamine amino acid precursors are being taken simultaneously. (8, 10-14) Peer-reviewed research has shown that urinary neurotransmitter testing is only useful when a person is in the competitive inhibition state. (8-11) Therefore, taking a ‘baseline’ assessment of urinary neurotransmitters does not provide any useful data.

For those of you familiar with laboratory testing, it would be similar to running a glucose tolerance test without taking a set amount of sugar. A glucose tolerance test measures your blood sugar levels at set times (usually 1, 2, and 4 hours) after consuming a specific amount of pure sugar (usually 75 grams). It requires that you fast for 8-12 hours before testing and consume nothing except the 75 grams of sugar before initiating the test. If you eat food before the test or do not take the exact amount of sugar at the right time, the results would be worthless from a clinical perspective – they would provide you numbers, but the numbers wouldn’t mean anything.

Likewise, simply running a urinary neurotransmitter test without taking a set amount of amino acids at the specified times results in a bunch of numbers on a page that are of no clinical value. The numbers are there, but they don’t mean anything. In order for the test to be accurate, you must be taking a set amount of amino acids for at least 7 days before testing.

What is Really Being Measured in Neurotransmitter Testing?

The confusion over testing urinary neurotransmitter levels is propagated by the very name “neurotransmitter testing”. This is because the actual levels of neurotransmitters found in the urine have nothing to do with the neurotransmitter levels in your brain. (15-19)

Even so, the urinary neurotransmitter levels do provide valuable information when someone is in the competitive inhibition state to help guide amino acid therapy. This is because there is a relationship between amino acid dosing, urinary output of neurotransmitters and the function of specific ‘gates’ in the kidneys called ‘transporters’. It is the transporter function which is the key to using urinary neurotransmitter testing to achieve clinically useful results. (11, 20, 21)