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Neurotransmitter Testing – Accuracy and Validity are Questionable

Lab scene representing neurotransmitter testing.

Although neurotransmitter testing has become popular among many different types of health care providers, the validity and accuracy of this method of assessment have been proven to be lacking. Not only that, following a nutritional supplement protocol based on these test results can be highly counterproductive and lead to a significant setback in health or the development of new issues.

Neurotransmitter Testing Results are Not Reliable

First and most importantly, the only true way to measure neurotransmitter levels in the brain is through cerebrospinal fluid (CSF). The lab tests that have become so trendy at this time are most often utilizing urine, but may also use blood (plasma) or saliva for analysis. None of these methods have proven to correlate with test results acquired through CSF. Blood (platelet) testing results correspond very closely to CSF, but only for dopamine, norepinephrine, and serotonin. However, blood platelet testing isn’t available outside the research setting at many labs besides Vitamin Diagnostics.

Mental health counselor and author of The Mood Cure, Julia Ross, writes in a Townsend article, that testing performed at Vitamin Diagnostics, by Dr. Audhya’s staff found that neither urine nor blood plasma results correspond to cerebrospinal fluid testing results. According to Dr. Audhyas, “levels of serotonin and the catecholamines are known to be stable and abundant in the blood platelets, but not in blood plasma, the levels of which are extremely reactive to stress (even the stress of the blood draw!). Additionally, “levels of neurotransmitters in urine vary rapidly in reaction to both stress, chemistry and diet-related (especially pH) changes.”

Ross also writes, “because neurotransmitter levels are so low in plasma, plasma testing is used primarily to track the dramatic increases in serotonin and catecholamines that can result from malignant tumors that secrete large amounts of one or the other of these neurotransmitters.” So they can be beneficial in this capacity.

When I was studying under Dr. Charles Gant at the Academy of Functional Medicine, I asked him if neurotransmitter testing was reliable and he said, it could be useful only for tracking malignant tumors that secrete neurotransmitters, but “it tells us nothing about what is going on in the brain.”

Neurotransmitters are produced in the gut in addition to the brain. The enteric nervous system sometimes referred to as the gut-brain, has 100 million neurons and manufactures more than 30 neurotransmitters that work independently from the brain to regulate gastrointestinal functions. However, only neurotransmitters produced in the brain can be accessed and used by the brain. Nutritional consultant and author of Primal Body Primal Mind, Nora Gedgaudas, explains, “as such, a urinary serotonin test is more likely a measurement of the neurotransmitter produced in the gut than serotonin produced in the brain.” I would add this would be true of any neurotransmitter, not just serotonin.

On the other hand, although neurotransmitters in the gut cannot be used by the brain, they do send signals to the brain via the vagus nerve, which can influence our mood, appetite, cognitive functions, memory, decision making, stress levels, and more. From birth to death, all microbes in the gut communicate with our brain, and may actually influence how our brain is wired. Therefore, changing the gut biome may change the way the brain is wired.

Furthermore, not only does our gut produce neurotransmitters, but so can the microbes that inhabit our gut. Microbes (both friendly and pathogenic) can create false neurotransmitters that can interact with neurons and impair enzymes needed for breaking down neurotransmitters. Thus, each of these scenarios can artificially influence levels that may be present in a urine test.

Neurotransmitter Levels Vary

Neurotransmitter levels vary greatly from day to day and even go up and down throughout the day in response to numerous other factors like our stress levels, the food we’ve eaten, blood sugar levels, exposure to environmental toxins, emotional conflict or trauma, demands of life, medications, herbal supplements, recreational drugs, alcohol, caffeine or nicotine use, and microbial overgrowth. Depending on the impact inflicted, this could lead to elevations or depletions at various times.

A neurotransmitter test provides results based on a particular moment in time when the sample is collected. Neurotransmitter levels could be vastly different minutes or hours after the test, even if we had a test that measures neurotransmitters in the brain effectively.

Other Factors that Impact Neurotransmitters

Additionally, there are many other factors that lab testing does not take into account. Even if you have optimal levels of neurotransmitters, there are other circumstances that can affect how well they are utilized or perform their functions.

  • There can be problems with neurotransmitter release, binding, or clearance.
  • Receptors (presynaptic or postsynaptic) may be too short or deficient in supply.
  • Receptor site sensitivity may be impaired.
  • Transmission can be disrupted by toxins like pesticides, herbicides, heavy metals, and microbes like Candida, bacteria, and parasites.
  • Neurotransmitters may not be broken down and recycled properly.
  • Other substances like toxins, recreational drugs, and medications can bind to or block receptors.
  • Neurons can fire too many or too little neurotransmitters.
  • Many toxins like pesticides and herbicides as well as microbes can inhibit or increase firing.
  • Poor handling of blood sugar, hormone imbalances, insufficient levels of oxygen, autoimmune diseases, and inflammation can all disrupt neurotransmitter function.
  • Neurons can become sensitized or desensitized, leading to either being trigger happy or lack a response.

Furthermore, if a leaky brain is present due to a breakdown in zonulin ( a substance that forms the blood-brain barrier) then undigested food particles, microbes, their toxins, and their false neurotransmitters may affect the brain’s neurons and neurotransmitters directly. Under normal circumstances, the blood-brain barrier would prevent these substances from reaching the brain.

So, even if you have optimal levels of neurotransmitters there can still be problems with production or function and the consequential symptoms associated with these issues. For example, you may exhibit classic signs of serotonin or dopamine deficiency, not because you have insufficient levels, but due to one of the issues mentioned above.

It’s important to note that if your symptoms are due to one of these other contributing factors, supplements designed to boost neurotransmitter levels are not likely to be effective, and may even make things worse.

Conflict of Interest for Providers of Neurotransmitter Testing

The biggest advocates for neurotransmitter testing are the laboratories that produce the tests and the nutritional supplements that are recommended based on the results received, and health care providers who are getting commissions for sending them clients. So there’s a serious conflict of interest to consider. Other health care professionals may simply be following the crowd without doing their homework to determine whether this is truly an effective method of assessment.

One of the most well-known labs promoting neurotransmitter testing is Neuroscience, which is part of Pharmassan Labs. You should be aware that Neuroscience (Pharmassan Labs) and CEO Gottfried Kellerman were fined 6.1 million dollars for “violating laboratory testing requirements and manipulating testing data.” They’ve also been found guilty of Medicare fraud.

NeuroScience admitted that it “intentionally reported neurotransmitter test results as high or low based not on a properly validated reference range, but based on a narrowed range that had not been subjected to method validation. Then recommended products to patients that fell outside of this narrowed and unvalidated range. These practices were not disclosed to CMS (Centers for Medicare and Medicaid Services).”

“Pharmasan, NeuroScience, and Kellermann agreed that the United States could demonstrate that their violation of CLIA regulations resulted in the submission and payment of false claims under the Medicare and TRICARE programs.”

Other labs providing this type of testing may not be unscrupulous, but they are misleading and clearly, have not done their due diligence in acquiring the facts.

Best Way to Test Neurotransmitters

The best way to test neurotransmitter levels is with your symptoms.

By understanding the purpose of key neurotransmitters and what happens when there is a problem with production or function in each one, we can make a very good educated guess about what neurotransmitters are high or low. Most individuals can make this assessment on their own simply by educating themselves on the role of neurotransmitters.

When I consult with a new client, I have a very thorough intake process, and the questions asked on my intake forms are designed to provide me with the information I need to determine which neurotransmitters may be out of balance based on their symptoms. Then we can discuss all the factors that may be contributing to this set of circumstances and the steps to be taken to improve things. If you need help figuring things out, you can schedule a consultation today.

Many practitioners like Dr. Charles Gant in End Your Addiction Now, Dr. Braverman in several of his books, and Julia Ross, M.A. in The Mood Cure have designed questionnaires that aid in determining your neurotransmitter levels.

Brain expert and author of Why Isn’t My Brain Working, Dr. Kharrazian, states, “There is no scientifically validated way to test neurotransmitter levels through lab testing. The best way is to assess your symptoms.”

Neurotransmitters are naturally occurring chemicals that facilitate communication between the brain and body. They control thoughts, moods, behaviors, cognitive functions, energy levels, gut function, circulation, immune response, motor functions sleep, appetite, sexual, metabolism, pain perception and management, vision, feelings of well-being and connectedness, and affect all aspects of our physical, mental, and spiritual health. It is estimated that 86 percent of Americans have sub-optimal levels.

Ensuring the proper production and function of these messengers and keeping them in balance is vital for our health and well-being and alleviating stress and anxiety. However, neurotransmitter testing is not needed to achieve this goal, so don’t waste your money, use your symptoms as your guide.


Nora Gedgaudas. The Whacky Wild and Misleading World of Neurotransmitter Testing. April 9, 2009.

Dan Hurley. Your Backup Brain. Psychology Today. November 1, 2011.

Getinet Ayano. Common Neurotransmitters: Criteria for Neurotransmitters, Key Locations, Classifications and Functions. Advances in Psychology and Neuroscience. Vol. 1, No. 1, 2016,

Department of Justice. U.S. Attorney’s Office. Nutritional Supplement Provider and CEO Plead Guilty & Agree to Pay Over $6.1 Million to Resolve False Claims Act Allegations.

Julia Ross. “Urinary Neurotransmitter Testing: Problems and Alternatives.” Townsend Letter October 2006.

Rob Stein. “Gut Bacteria Might Guide the Workings of Our Minds.” National Public Radio. November 18, 2013.

Hinz, Marty et al. “Neurotransmitter Testing of the Urine: A Comprehensive Analysis.” Open Access Journal of Urology 2 (2010): 177–183. PMC. Web. 14 Nov. 2017.

Hinz, M., Stein, A., & Uncini, T. (2011). Validity of urinary monoamine assay sales under the “spot baseline urinary neurotransmitter testing marketing model.” International Journal of Nephrology and Renovascular Disease, 4, 101–113.

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