HPA (NeuroLab)

NeuroLab is a leading specialist in the research, analysis, and development of biomarkers associated with hypothalamic-pituitary-adrenal (HPA) axis function. Optimal HPA function is foundational to peak performance of the body’s neuroendocrine communication system.

Afternoon Cortisol

Optimal range: 2.3 - 5.3 nm

Cortisol is a hormone produced by the adrenal glands, which are located on top of the kidneys. It is normally released in response to events and circumstances such as waking up in the morning, exercising, and acute stress.


Afternoon DHEA-s

Optimal range: 1 - 6 ng/mL


Optimal range: 0 - 0 mg/dL

Creatinine is used to calculate results and is not to be used diagnostically.



Optimal range: 250 - 400 ug/g Cr

Dopamine is a neurotransmitter that activates the brain’s reward center during pleasurable activities.

Optimal dopamine function is involved in many aspects of health, including memory, movement, motivation, mood, attention, sleep, arousal, learning, and lactation.

What is dopamine and what are its functions?

Dopamine is a neurotransmitter (= chemical messenger) that is produced in large concentrations during pleasurable activities such as when eating sugar or junk food, having sex, or participating in fun and enjoyable down-time activities like spending time in nature or engaging in a favorite hobby. Dopamine is released during these times as a reward for engaging in the activities necessary for survival and reproduction such as eating, drinking, and competing.



Optimal range: 10 - 15 ug/g Cr

Epinephrine, also known as adrenaline, is a monoamine that serves as both a stress hormone and an excitatory neurotransmitter. It is produced by chromaffin cells within the adrenal medulla of the adrenal gland and is secreted into the bloodstream during acute stress. Epinephrine rapidly provides the body with the energy and alertness necessary to produce an appropriate response to stressors. It does this by binding to alpha and beta adrenergic receptors throughout the body and changing how various organs function, including the heart, blood vessels, lungs, liver, eyes, and digestive system. Most of the body's epinephrine acts as a hormone, and only a small amount acts as a neurotransmitter. The catecholamine synthesis pathway begins with the uptake of the amino acid tyrosine into the cytoplasm and ends with the production of epinephrine through a series of enzymatic reactions.


Evening Cortisol

Optimal range: 1 - 2.4 nm

Cortisol is a hormone produced by the adrenal glands, which are located on top of the kidneys. It is normally released in response to events and circumstances such as waking up in the morning, exercising, and acute stress.



Optimal range: 600 - 1100 ug/g Cr

GABA is a neurotransmitter that occurs naturally and is known for its calming effects on the body. It is also associated with regulating the sleep/wake cycle. If we experience feelings of anxiety or hyperactivity, it could indicate an imbalance in GABA levels. This imbalance could also lead to sleep disturbances, ranging from difficulty sleeping to excessive drowsiness, depending on the severity of the imbalance. Testing for GABA levels can help identify the extent of the imbalance and the best approach to correcting it. A diet rich in GABA-containing foods, its precursor, and cofactors can help correct high or low levels of GABA.

What Does GABA Do?

GABA is an inhibitory neurotransmitter produced in the brain. GABA is also produced and functions in the periphery. As an inhibitory neurotransmitter, GABA blocks excitatory neurotransmitters by decreasing stimulation of nerve cells. This blocking action by GABA leads to the calming effect that GABA is known to produce, which helps reduce anxiousness, regulate sleep, and make us feel calmer.

What Happens When You Have a GABA Imbalance?

Imbalanced GABA levels are associated with a number of health concerns that impact quality of life. For example:

  • Mental and Emotional Health
    • Low GABA symptoms include anxiousness, sad feelings, and mood swings. 6
  • High GABA symptoms include poor cognition/difficulty concentrating and difficulties with memory.
  • Sleep Disruptions
  • Poor sleep, including difficulty falling and staying asleep, is linked to GABA deficiency. 5

How Does GABA Become Imbalanced?

A number of factors can disrupt GABA levels or associated hormones and neurotransmitters. These factors include:

  • Alcohol consumption. Over time alcohol intake can cause down-regulation of GABA receptors, resulting in low GABA levels. 8
  • Poor diet or maldigestion. The nutrients and cofactors found in foods necessary to make GABA can affect GABA levels. 3 Therefore, a poor diet can potentially cause low GABA levels. Some people can eat a healthy diet but due to maldigestion or malabsorption, they may still have low GABA.
  • Stress. Over time stress can cause elevated levels of epinephrine, norepinephrine, and dopamine. As GABA rises to inhibit the effect of these catecholamines, it can become depleted. 9

How Can We Naturally Support GABA?

It is possible to encourage healthy levels of GABA through lifestyle measures, including:

  • Consuming foods that contain GABA, or support its production, may help increase GABA levels.
    High GABA foods include: 3
    • Brown rice
    • Cruciferous vegetables (Brussels sprouts, broccoli, cauliflower, cabbage)
    • Mushrooms
    • Spinach
    • Sprouted grains
    • Sweet potatoes
    • Tomatoes
  • Dietary supplements containing ingredients that support GABA receptors can reduce symptoms associated with imbalanced GABA. These supplements can also support the inhibitory properties of GABA and symptoms associated with low GABA: 15-18
    • L-Theanine
    • Magnesium
    • Taurine
  • Patients can take GABA in a supplement form to improve GABA levels. Vitamin B6 is also an important cofactor in the production of GABA from glutamic acid.
  • Exercise, such as high-intensity exercise, can also increase GABA levels. 19



Optimal range: 5 - 10 mg/g Cr

Glutamate is a vital neurotransmitter in the central nervous system, involved in almost all significant excitatory brain functions. It is the primary and most abundant excitatory neurotransmitter, and it's estimated that over half of all neural synapses release glutamate, making it a critical player in neural circuit communication.

Glutamic acid and glutamate are essentially interchangeable terms. The two molecules are almost identical, except that glutamic acid has an additional proton, or hydrogen atom. In physiological conditions, glutamic acid sheds this extra proton and becomes glutamate, the abundant form of the amino acid in the human body.

Glutamate is a crucial excitatory neurotransmitter that plays a vital role in maintaining healthy brain and nervous system function. It enables us to learn, remember, feel, sense, and coordinate our movements effectively.


Morning Cortisol

Optimal range: 5.1 - 11.6 nm

Morning DHEA-s

Optimal range: 1 - 6 ng/mL

Night Cortisol

Optimal range: 0.4 - 2.1 nm

Norepi/Epi Ratio

Optimal range: 0 - 13 Ratio


Optimal range: 30 - 50 ug/g Cr

Norepinephrine, also known as noradrenaline, is important for mental focus and emotional stability.

Norepinephrine functions as a neurotransmitter and hormone that regulates the “fight or flight” response and elevates blood pressure and heart rate, stimulates wakefulness, and reduces digestive activity.



Optimal range: 1.64 - 7.27 mcg/g Cr

PEA stands for Beta-phenylethylamine and is an excitatory neurotransmitter made from phenylalanine and it modulates neuron voltage potentials to favor glutamate activity and neurotransmitter firing.



Optimal range: 125 - 260 ug/g Cr

Serotonin is one of our happiness neurotransmitters that makes us feel good. When we are feeling anxious it can be a sign of serotonin imbalance. In addition to mood concerns, serotonin imbalance may also show up as sleep disruptions, gut issues, or cravings and urges; among many other complaints. Because it plays a role in regulating several physiological processes, serotonin testing is helpful to identify serotonin imbalances. Low or high serotonin levels can be corrected with diet and lifestyle.

How does Serotonin become imbalanced?

A number of factors can disrupt serotonin levels or associated hormones or neurotransmitters. These factors include:

  • Digestive issues. Problems digesting food can lead to impaired absorption and breakdown of the precursors and cofactors necessary for building neurotransmitters. 24
  • Poor diet. A diet lacking in the nutrients needed to make serotonin can affect levels of this neurotransmitter. 25
  • Stress. Modern levels of stress can cause a cascade of symptoms, including decreased levels of serotonin, oxidative stress, and cortisol imbalances. 26

How can we naturally support Serotonin?

It is possible to encourage healthy levels of serotonin through lifestyle measures, including:

  • Eating foods rich in the amino acid building block and cofactors needed to make serotonin. 
  • Dietary supplements that contain the necessary precursors and cofactors to promote the synthesis, release, and/or function of serotonin can also support healthy levels of serotonin. These include:
    • L-tryptophan
    • 5-hydroxytryptophan
    • Vitamin B6 (as pyridoxal-5-phosphate)
    • Iron
  • Exercise, even at moderate levels a few times a week, can increase serotonin levels while also improving stress, mood, and cognition. 33
  • Meditation has been shown to increase serotonin levels, while also reducing stress and anxiousness. 34 Additionally, meditation may also aid in improving other indicators of serotonin imbalance such as cognition and memory.