Mood
Gut & brain
Serotonin
A neurotransmitter and hormone involved in mood, appetite and digestion.
What it does
- Contributes to feelings of wellbeing and calm
- Regulates appetite, sleep and gut movement
Too much
- Excess (e.g. serotonin syndrome from drug interactions) causes agitation and rapid heartbeat
Too little
- Low activity is associated with low mood and anxiety in some people
Keeping it balanced: Daylight, exercise, and a varied diet (tryptophan, gut health) support serotonin.
Sources & references
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.
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