Serotonin plays a key role in body functions, such as mood, sleep, wound healing and bone health, and inappropriate serotonin levels can cause physical and mental health problems. So what is serotonin? And what are its roles? And how can you raise its percentage in the blood?

Serotonin, also known as 5-hydroxytryptamine (5HT), is a monoamine neurotransmitter and a hormone in the body.

Serotonin carries messages between neurons in your brain and throughout your body, and these chemical messages tell your body how to function, according to the Cleveland Clinic.

Serotonin excretion in the body

Most serotonin is found in the gut, about 90 percent of it is concentrated in the cells lining your digestive system, compared to just 10 percent in your brain, released into the circulatory system and absorbed by platelets.

Serotonin is composed of the essential amino acid tryptophan. The term "essential amino acid" means that your body cannot make it, and it must be obtained from the foods you eat.

Serotonin functions

Serotonin plays a role in many bodily functions such as:

  • Mood: Serotonin regulates your mood, so when it's at normal levels, you feel more focused, emotionally stable, happy and calm, while low levels are associated with depression. Many medications used to treat anxiety, depression and other mood disorders often target ways to increase the level of serotonin in your brain.
  • Digestion:Your intestines can increase the secretion of serotonin to speed up digestion to rid your body of irritating foods or toxic products, and serotonin also plays a role in reducing your appetite while eating.
  • Nausea: Nausea occurs when serotonin is released into your gut faster than it can digest, and many medications used to reduce nausea and vomiting target specific serotonin receptors in your brain.
  • Sleep: Serotonin, along with another neurotransmitter dopamine, plays a role in the quality of your sleep (how well and how long you sleep). Your brain also needs serotonin to make melatonin, a hormone that regulates the sleep-wake cycle. It also causes the smallest blood vessels to narrow, slowing blood flow and helping clots form, an important process in wound healing.
  • Bone health: Serotonin levels may play a role in your bone density, and high levels may cause bone weakening, which can lead to bone fractures and fragility.
  • Sexual health: Serotonin plays a role – along with the neurotransmitter dopamine – in the desire for sex.

Effects of low serotonin

Low levels of serotonin may be associated with several conditions including:

  • Depression and other mood problems
  • anxiety
  • Sleep problems
  • Digestive problems
  • Suicidal behavior
  • Obsessive-compulsive disorder
  • Post-traumatic stress disorder
  • Panic disorders
  • Schizophrenia
  • Phobias

Causes of low serotonin

Serotonin levels may be low for the following reasons:

  • The body does not produce enough serotonin
  • The body does not use serotonin effectively, and this can happen if you don't have enough serotonin receptors or if the receptors aren't working as they should.

How do I increase my serotonin levels?

Ways to increase serotonin levels include:

  • Eat more foods that contain tryptophan
  • Get more sunlight
  • Do more exercise
  • Reduce your stress level

Foods that increase serotonin levels

Many foods naturally contain tryptophan, the amino acid that makes up serotonin. You can try to increase your serotonin level by eating foods, such as:

  • Salmon
  • Eggs
  • Cheese
  • Turkey meat
  • Tofu
  • Pineapple
  • Nuts
  • Oats
  • Seeds

Eating foods high in tryptophan will not necessarily increase serotonin levels, it is a complex process, and your body needs carbohydrates to release the insulin needed to absorb amino acids. Then even if tryptophan gets into your blood, it must compete with other amino acids to be absorbed in your brain.

Scientists are still studying how eating foods containing tryptophan can increase serotonin levels.

Medications that increase serotonin levels

Several different classes of antidepressants prevent the reabsorption and recycling of serotonin, allowing more to remain in the brain.

Drugs that work in this way are:

  • Selective serotonin reuptake inhibitors
  • Serotonin-norepinephrine reuptake inhibitors
  • Tricyclic antidepressants
  • Monoamine oxidase inhibitors

Problems associated with high serotonin levels

Serotonin syndrome is a condition that occurs when levels increase too much, usually if you increase the dose of a drug known to increase serotonin levels.

Mild symptoms of high serotonin levels include

  • Shivering
  • Heavy sweating
  • Confusion
  • Insomnia
  • Hypertension
  • Muscle cramps
  • Diarrhea

Severe symptoms of high serotonin levels include

  • Overheating
  • Seizures
  • Fainting
  • Abnormal heartbeat

Serotonin syndrome can be fatal if it is severe, not detected early and treated quickly.