Adrenaline—also known as epinephrine—is both a hormone and a life-saving medication. It plays a vital role in your body’s ability to respond to acute stress and is commonly used in emergency medicine to treat severe allergic reactions, cardiac arrest, and other critical conditions.

Produced naturally by the adrenal glands, adrenaline is best known for powering the “fight-or-flight” response. It prepares the body to either confront or flee a perceived threat by activating the sympathetic nervous system. In a matter of seconds, it floods the bloodstream, influencing various organs and systems to help you react quickly.

Understanding how adrenaline works—and when it’s used as a medication—can be essential for managing emergencies and maintaining overall health.

The Role of Adrenaline in the Body

As a hormone, adrenaline has wide-ranging effects on nearly every part of the body. It serves as a messenger that prepares your system for fast action in times of immediate stress or danger.

Key functions of adrenaline include:

  • Stimulating the sympathetic nervous system to initiate a rapid fight-or-flight response

  • Increasing heart rate and boosting the force of heart contractions

  • Expanding airways to improve oxygen intake

  • Widening pupils to enhance visual sensitivity

  • Increasing blood flow to muscles and vital organs

  • Inhibiting non-essential functions like digestion

  • Enhancing glucose production and release for energy

  • Contracting specific muscles, such as those in the intestines and blood vessels

These responses allow the body to redirect energy toward survival during moments of acute stress, such as escaping danger or reacting to trauma.

Normal Adrenaline Levels and Imbalances

Adrenaline levels in the body are typically measured in picograms per milliliter (pg/mL) or picomoles per liter (pmol/L). The normal range is between 0–140 pg/mL, or up to 764.3 pmol/L.

Factors that influence adrenaline levels include:

  • Emotional or physical stress

  • Stimulants like caffeine or nicotine

  • Intense exercise

  • Medical conditions affecting the adrenal glands

Testing adrenaline levels:
Doctors may order a catecholamine test, which measures the amount of adrenaline and other related hormones (like norepinephrine) in blood, urine, saliva, or hair. These tests help identify underlying hormonal imbalances or rare conditions like pheochromocytoma, a tumor that causes excessive adrenaline production.

Low and High Adrenaline: What They Mean

Low adrenaline levels are relatively uncommon. When they do occur, they may impair your ability to handle stress. Symptoms can include fatigue, dizziness, or poor concentration. In most cases, low levels are managed by addressing underlying adrenal dysfunction.

High adrenaline levels are more frequently seen and may result from:

  • Chronic stress

  • Excessive caffeine or stimulant use

  • Alcohol or drug consumption

  • Intense physical exertion

  • Tumors of the adrenal gland (e.g., pheochromocytoma)

Common symptoms of high adrenaline include:

  • Jitteriness or shakiness

  • Rapid heart rate (tachycardia)

  • Elevated blood pressure

  • Weight loss

  • Anxiety or panic-like symptoms

  • Insomnia

Treatment for high adrenaline depends on the cause. Tumors, for instance, may require surgical removal or medication to regulate hormone production.

Medical Uses of Adrenaline

Adrenaline is not just a naturally occurring hormone—it’s also used as a medication in emergency healthcare. It belongs to a drug class known as alpha- and beta-adrenergic agonists, which mimic the body’s own stress hormones.

Common medical applications for adrenaline include:

  • Anaphylaxis: Adrenaline is the first-line treatment for life-threatening allergic reactions to foods, insect stings, or medications.

  • Cardiac arrest: Used in advanced cardiac life support (ACLS) protocols to restart the heart.

  • Septic shock: Helps stabilize blood pressure in patients experiencing dangerously low circulation from infection.

  • Newborn resuscitation: Administered during neonatal emergencies to restore cardiac function.

  • Asthma attacks: Sometimes used to relieve airway constriction in severe cases.

  • Open-angle glaucoma: Occasionally used in eye drops to reduce intraocular pressure.

Adrenaline works quickly to constrict blood vessels, relax airway muscles, and improve blood flow—making it indispensable in time-sensitive situations.

How To Use Adrenaline Safely

Most people encounter adrenaline in the form of an auto-injector, like an EpiPen, which is designed for self-administration during an anaphylactic reaction.

Key instructions for use:

  • Inject into the outer thigh muscle at the first signs of an allergic reaction (e.g., swelling, difficulty breathing, hives)

  • Call emergency services immediately after injection

  • Follow up with professional medical treatment, even if symptoms improve

  • Avoid injecting into a vein or buttocks unless directed by a healthcare provider

In hospital settings, adrenaline may also be given intravenously by medical professionals under controlled conditions.

Safety Precautions and Contraindications

Adrenaline should be used with caution, especially in individuals with pre-existing health conditions or drug sensitivities.

Before using adrenaline, tell your healthcare provider if you have:

  • Heart disease or arrhythmia

  • Hypertension (high blood pressure)

  • Diabetes

  • Hyperthyroidism

  • Glaucoma

  • Parkinson’s disease

  • Asthma or COPD

  • Mental health disorders such as anxiety or depression

Drug interactions:
Adrenaline may interact with common medications such as:

  • Antihistamines like diphenhydramine (Benadryl)

  • MAO inhibitors or certain antidepressants

  • Beta-blockers, which may reduce adrenaline’s effectiveness

Pregnant or breastfeeding individuals should only use adrenaline if the potential benefits clearly outweigh the risks, as data on human safety is limited.

Potential Side Effects of Adrenaline Medication

Like all medications, adrenaline can cause side effects—some mild, some severe.

Possible side effects include:

  • Tremors

  • Dizziness

  • Headache

  • Nervousness or anxiety

  • Sweating

  • Nausea or vomiting

  • Rapid heartbeat

  • Skin flushing or redness

Severe or rare side effects:

  • Intracerebral hemorrhage (bleeding in the brain)

  • Tissue necrosis (death of skin or muscle) if improperly injected

  • Allergic reactions (ironically, though rare)

To avoid complications, always follow dosing instructions and seek emergency help if any severe reactions occur. If you think you’ve overdosed, call Poison Control at 1-800-222-1222.

Natural Ways to Increase Adrenaline

While medical use of adrenaline is reserved for emergencies, some people seek adrenaline "rushes" through lifestyle activities that naturally stimulate the hormone.

Activities that trigger natural adrenaline release include:

  • High-intensity workouts

  • Adventure sports like skydiving or bungee jumping

  • Watching horror movies or thrillers

  • Public speaking or performing

  • Competitive sports and challenges

These temporary spikes in adrenaline can boost energy, improve focus, and enhance physical performance. However, regular exposure to high-stress stimulation can be harmful if not balanced with recovery and relaxation.

Summary: Why Adrenaline Matters

Adrenaline, or epinephrine, is one of the body’s most powerful hormones—and one of modern medicine’s most critical emergency treatments. Whether you're managing a severe allergy, undergoing surgery, or reacting to danger, adrenaline mobilizes your body’s defenses and keeps you alive during extreme situations.

While it plays a crucial role in your short-term stress response, chronic elevation of adrenaline can lead to long-term health concerns. Understanding how this hormone works, when it should be used, and how to manage its effects is essential for both patients and caregivers.

If you're prescribed adrenaline, make sure you know how to use it properly—and talk to your doctor about any questions or concerns related to its safety or side effects.