Discovery and naming
In 1901 Japanese chemist Jokichi Takamine and his assistant Keizo Uenaka isolated a blood-pressure-raising substance from cattle adrenal glands in crystalline form and sold it under the trade name Adrenalin. Around the same time John Jacob Abel in the United States studied the same substance and called it epinephrine. Both names mean "on the kidney," one from Latin and one from Greek; Europe generally uses adrenaline, while the US Pharmacopeia uses epinephrine. It is often described as the first hormone ever isolated in pure form.
The fight-or-flight response
In 1915 Harvard physiologist Walter Cannon coined "fight or flight" to describe how the sympathetic nerves and adrenal glands act together when an animal senses danger. Within seconds of adrenaline release, the heart beats faster and harder, airways widen, the liver breaks down glycogen to raise blood sugar, pupils dilate and blood is diverted away from the gut. Its close relative noradrenaline mainly acts at nerve endings to constrict blood vessels and sharpen alertness. Long-term stress is handled by cortisol, while adrenaline is the immediate responder. When this surge fires without real danger, it produces the core symptoms of a panic attack.
Adrenaline as a medicine
Adrenaline is on the WHO Model List of Essential Medicines. An intramuscular injection into the thigh is the first-line treatment for anaphylaxis, the severe allergic reaction that can follow peanuts or insect stings, which is why at-risk people carry auto-injectors such as the EpiPen. It is used in cardiac arrest resuscitation and is mixed into local anesthetics to reduce bleeding. Tumors such as pheochromocytoma that overproduce it cause episodes of high blood pressure and palpitations. "Adrenaline junkie" is not a medical term but a description of thrill-seeking, and that buzz also involves dopamine.
This article is general health information and is not a substitute for diagnosis or treatment. If symptoms persist, see a doctor.
FAQ
- Are adrenaline and epinephrine different substances?
- No, they are the same molecule. The names simply come from Latin (ad renal) and Greek (epi nephros) words for the adrenal gland.
- Do I still need the hospital after using an EpiPen?
- Yes. The effect lasts only about 15–20 minutes and symptoms can return, so call emergency services and get checked in an emergency department.
Sources reviewed: 2026-10-26
References
- Cannon, W. B. (1915). Bodily Changes in Pain, Hunger, Fear and Rage. D. Appleton and Company.
- Takamine, J. (1901). The isolation of the active principle of the suprarenal gland. The Journal of Physiology, 27(Suppl), xxix–xxx.
- Shaker, M. S., et al. (2020). Anaphylaxis—a 2020 practice parameter update. Journal of Allergy and Clinical Immunology, 145(4), 1082–1123.