Stress Adrenal medulla

Adrenaline (Epinephrine)

Written by the VitaWhat editorial team · Medically reviewed by Steve Davis · Last reviewed 19 July 2026 · Editorial policy

The rapid "fight or flight" hormone released in moments of danger or excitement.

What it does

  • Speeds up heart rate and breathing
  • Diverts blood to muscles
  • Releases glucose for quick energy

Too much

  • Excess (e.g. a phaeochromocytoma tumour) causes racing heart, sweating and high blood pressure

Too little

  • Rarely deficient
  • used as a medicine (EpiPen) to reverse severe allergic reactions
Keeping it balanced: Regular relaxation and exercise help the body recover after adrenaline surges.

Sources & references

  1. You and Your Hormones (Society for Endocrinology)
  2. NHS — Hormonal conditions

Think a hormone may be out of balance?

The symptoms of hormonal excess and deficiency are non-specific — tiredness, weight change, low mood and poor sleep have many everyday causes. No hormone problem can be self-diagnosed from a symptom list.

Diagnosis needs blood tests interpreted alongside your history, sometimes repeated at set times of day because many hormones vary hour to hour. Speak to a GP if symptoms are persistent; seek urgent care for severe symptoms such as confusion, fainting, chest pain or extreme thirst with frequent urination.

Related entries

CortisolNoradrenaline (Norepinephrine)AldosteroneCalcitoninDopamineErythropoietin (EPO)
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