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What is serotonin?

Serotonin is a chemical that has several important jobs in the body. It’s a natural mood stabiliser that controls wellbeing and happiness. Not having enough serotonin is thought to contribute to depression.

Serotonin is manufactured by the body’s nerve cells. It is formed during a chemical reaction involving a protein called tryptophan.

Serotonin is found throughout the body, but mainly in the intestines, brain and blood. It helps your body to work properly by sending messages between the nerve cells.

What is the role of serotonin?

Serotonin has many different roles. It helps control the muscles and how you move, and it influences appetite and how your bowels work. It is used to push out food when you vomit or have diarrhoea. It also helps your blood to clot, to heal wounds, and it plays a role in the health of your bones.

It’s also very important in the brain. Serotonin controls your mood and is responsible for happiness. It helps regulate when you sleep and wake, helps you think, maintains your mood, and controls your sexual desire.

Boosting serotonin levels can help with depression, anxiety, obsessive-compulsive disorder, social anxiety disorder, panic disorder and post-traumatic stress disorder (PTSD).

What happens if I have too little serotonin?

If you don’t have enough serotonin, you are more likely to develop depression and anxiety. You need the right amount of serotonin to feel happy, calm and emotionally stable.

The symptoms of low serotonin levels include:

  • memory problems
  • feeling low
  • craving sweet foods
  • having problems sleeping
  • feeling bad about yourself
  • increased libido (sexual desire)

Recreational drugs such as MDMA (ecstasy) cause large amounts of serotonin to be released. This can mean your serotonin levels end up low, leading you to feel depressed and confused for a few days. Over time, it’s thought that drug use can damage the nerves that produce serotonin.

What happens if I have too much serotonin?

Having too much serotonin can lead to serotonin syndrome, which can be life threatening in some people. It’s almost always caused by taking certain medications with antidepressant medicines. It usually disappears when you stop taking the medicines, but it is very important to see a doctor if you think you may have serotonin syndrome. It is usually treated in hospital.

Serotonin syndrome usually happens after your medicine dose has been increased, or if you have taken antidepressant medicines along with other prescription medicines, natural medicines or illegal drugs that also increase serotonin. Symptoms include:

High levels of serotonin can also reduce your libido (sexual desire).

Sometimes high levels of serotonin are a sign that you have a tumour in an organ, in your stomach or lungs.

How can I adjust my serotonin levels?

Serotonin levels can be increased naturally by getting more exposure to outdoor sunlight and by doing plenty of exercise. It can also help to eat more foods that contain tryptophan, such as nuts, eggs, cheese, red meat, turkey, salmon, tofu and pineapple.

Counselling and meditation are ways to improve your mood that are also thought to boost serotonin levels.

Medicines that are used to increase serotonin levels and treat depression are known as selective serotonin reuptake inhibitors (SSRIs). These medicines work by preventing serotonin from being reabsorbed back into the nerve cells.

It’s important to always follow your doctor’s instructions when taking SSRIs. You should never mix them with other medicines or illegal drugs, and never stop taking them without talking to your doctor first.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: April 2021

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