Epinephrine: Understanding Your Adrenaline Levels

What Is Epinephrine?

Epinephrine, also known as adrenaline, is a hormone and neurotransmitter produced primarily by the adrenal medulla, the inner portion of your adrenal glands. It belongs to a group of chemicals called catecholamines, which also includes norepinephrine and dopamine. Epinephrine plays a central role in your body’s “fight-or-flight” response, the rapid set of physiological changes that occur when you perceive stress, danger, or excitement.

When released, epinephrine increases heart rate, raises blood pressure, opens airways in the lungs, redirects blood flow to muscles, and boosts the breakdown of glycogen into glucose to provide quick energy. These effects are typically short-lived, since epinephrine is metabolized quickly. Because levels can shift dramatically with stress, posture, and activity, interpreting an epinephrine measurement always requires clinical context.

What the Test Measures

An epinephrine test measures the amount of this hormone circulating in your blood or excreted in your urine. Because catecholamines are released in bursts and cleared rapidly, clinicians often measure not only epinephrine itself but also its breakdown products, called metanephrines, which provide a more stable picture of overall catecholamine activity.

This testing may be ordered when a clinician is evaluating:

• Episodes of unexplained high blood pressure, especially when it comes in spells
• Symptoms such as rapid heartbeat, sweating, headaches, tremor, or anxiety
• The possibility of a catecholamine-secreting tumor such as a pheochromocytoma or paraganglioma
• Adrenal gland function as part of a broader hormonal evaluation

Epinephrine Reference Ranges

Reference ranges can vary by laboratory and by the conditions under which the sample is collected (for example, lying down versus standing). The values below represent commonly used standard ranges. Always interpret your result against the range printed on your own lab report.

Units may be reported differently depending on the lab. Plasma values are often given in picograms per milliliter (pg/mL), while urine values are typically reported in micrograms per 24 hours (mcg/24 hr).

What High Levels Can Mean

Elevated epinephrine can have many causes, and a high reading does not by itself confirm any specific diagnosis. Possible contributors include:

• Acute stress or anxiety at the time of collection, which is one of the most common reasons for transiently elevated levels
• Strenuous physical activity before the test
• Certain medications, including some decongestants, stimulants, and blood pressure agents
• Caffeine, nicotine, or other stimulants consumed before testing
• Catecholamine-secreting tumors such as pheochromocytoma, which require careful medical evaluation
• Low blood sugar, which can trigger a compensatory adrenaline release

Because so many everyday factors can raise epinephrine, your clinician will consider your symptoms, repeat testing, and additional studies before drawing conclusions.

What Low Levels Can Mean

Low epinephrine is less commonly a focus of concern than high levels, and very low resting values can fall within normal expectations for many people. In some situations, reduced catecholamine output may be associated with:

• Adrenal insufficiency or conditions affecting the adrenal medulla
• Autonomic nervous system dysfunction, which can affect blood pressure regulation and the body’s stress response
• Effects of certain medications that suppress the sympathetic nervous system

Interpreting low values requires correlation with other hormones, blood pressure patterns, and your overall clinical picture.

How the Test Is Done

Epinephrine can be measured through a blood draw, a 24-hour urine collection, or both. Because the hormone is so sensitive to stress and posture, preparation matters:

• You may be asked to rest quietly, sometimes lying down, for a period before a blood sample is drawn.
• Your clinician may advise avoiding caffeine, nicotine, and strenuous exercise for a set time beforehand.
• Certain foods and medications may need to be paused, but only under your clinician’s guidance — never stop a prescribed medication on your own.
• For a 24-hour urine test, you collect all urine over a full day into a special container.

Following collection instructions carefully helps reduce false elevations and improves the reliability of your results.

Putting Your Number in Context

A single epinephrine value is only a snapshot taken at one moment in time, and adrenaline naturally fluctuates throughout the day. At ENNU Life, we view biomarkers not as isolated numbers but as part of a larger story about how your body is functioning. Rather than asking only whether a result falls inside a broad “normal” laboratory range, we consider what an optimal range may look like for you and how your values trend over time.

Epinephrine is best understood alongside related measurements — norepinephrine, metanephrines, cortisol, blood sugar, blood pressure, and your reported symptoms. Looking at these together can help your clinician explore root causes of issues like persistent stress responses, fatigue, or unexplained blood pressure changes, rather than focusing on a single result in isolation.

Because epinephrine testing can carry significant implications, any result — high, low, or normal — should be interpreted by a qualified clinician who knows your full history. Your provider can determine whether repeat testing, additional studies, or further evaluation may be appropriate, and can help you understand what your numbers mean for your individual health.