The brain contains billions of nerve cells that pass messages to one another using chemicals. Fast messengers carry a signal across the tiny gap between two cells in a fraction of a second. Slower messengers adjust how strongly whole networks respond, shaping mood, motivation, stress and alertness over minutes to hours.
Two kinds of messenger
- Small messengers. Serotonin, dopamine and others. These are made from single amino acids.
- Larger messengers. Short chains of amino acids, known as peptides. The brain uses more than a hundred of them to fine-tune stress response, sleep, appetite, pain and social behaviour. The body's natural endorphins belong to this group.
The brain also produces protein growth factors that help nerve cells survive, form new connections and adapt. These connections are the physical basis of learning and memory.
Where amino acids come in
- Serotonin is made from the amino acid tryptophan.
- Dopamine and noradrenaline are made from tyrosine.
- The brain's main calming messenger is made from glutamate.
- The larger peptide messengers and growth factors are built from chains of amino acids.
The brain makes these messengers itself from what the diet supplies, and tightly controls what crosses from the blood into brain tissue.
What influences brain and mood
- Sleep, when the brain consolidates memories
- Regular physical activity, which is linked to higher levels of the brain's growth factors
- Balanced nutrition
- Long-term stress
- Social connection and mental stimulation
This article is for general educational purposes only and is not medical advice.
Frequently asked questions
How do brain cells communicate?
By releasing chemical messengers that cross the small gap between cells and bind to receptors on the next cell.
What is the link between amino acids and mood?
Several of the brain's key messengers are made directly from amino acids, and others are short chains of them.
What are endorphins?
They are natural peptides made by the body that help moderate pain and are associated with a sense of wellbeing, for example after exercise.
Why does sleep affect mood and focus?
Sleep is when the brain consolidates memory and resets its signalling systems. Too little sleep affects attention, mood and stress tolerance.
Can exercise affect the brain?
Yes. Regular activity is associated with better mood and with higher levels of the growth factors that support nerve cells.
Is this medical advice?
No. This article is general educational information. Speak to a qualified healthcare professional about mental health concerns.