Serotonin: Function, Side Effects, Benefits, and More


Serotonin is a neurotransmitter that transmits signals between nerve cells. The main function of serotonin is to stabilize your mood, as well as feelings of happiness and well-being. It also plays a role in the way that brain cells and the nervous system interact with each other, and it also affects the digestive system and sleep cycles.

Serotonin is found in the body's digestive system, as well as the central nervous system and platelets. The central nervous system is made up of the brain and spinal cord . It controls most of the functions of the body and mind.

The body produces serotonin using tryptophan hydroxylase, an amino acid, and creates a chemical reaction that forms a neurotransmitter. Although the body needs serotonin to function, too much or too little serotonin can lead to health problems. For example, too little serotonin can cause depression, and too much serotonin can cause serotonin syndrome, a rare condition that ranges from mild to severe.

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Serotonin is responsible for regulating mood. It can reduce feelings of depression and anxiety and increase feelings of joy or happiness.

It also plays a vital role in other aspects of our health, including:

  • Sleep – When you sleep, serotonin stimulates the areas of the brain that control sleep and wake behavior.
  • Intestinal emptying: Since most of the body's serotonin is found in the digestive system, it affects the functioning of the intestines and plays a role in controlling bowel movements.
  • Blood clotting: When you have a wound, the platelets in your body use serotonin to help it heal faster. Serotonin promotes the formation of blood clots and the narrowing of some tiny arteries.
  • Nausea Nausea is caused by serotonin. When food that your stomach disagrees with enters your digestive system, your body produces more serotonin. This forces the body to excrete food faster than normal. When the production of serotonin in the blood increases, it triggers a reaction in the part of the brain that controls the feeling of nausea.
  • Bone Health: Studies have shown that osteoporosis , which makes or weakens bones, can be caused by high levels of serotonin in the body, which means that having adequate levels of this neurotransmitter contributes to overall bone health.
  • Sexual function – When serotonin levels get too high, it can lead to decreased libido. On the other hand, if the levels drop too low, you may experience a more intense libido or arousal than usual.

Serotonin deficiency

The causes of serotonin deficiency include:

  • Low Tryptophan – If your body doesn't have enough of this amino acid, it can't make enough serotonin.
  • Specific Nutrients: Studies have shown that vitamin D and omega-3 fatty acids can modulate the formation, release, and function of serotonin. This is because tryptophan is highly dependent on vitamin D. Omega-3s have also been shown to help modulate brain dysfunction due to their effect on serotonin production.
  • Not Enough Serotonin Receptors – Too few serotonin receptors, or receptors that don't work, can lead to depression and an increased risk of suicide, which is a trademark of serotonin deficiency.
  • Stress: Studies have shown that high levels of stress in childhood can lead to decreased serotonin levels in adulthood. Experiencing traumatic events while the brain is still developing can cause a dysregulation of serotonin levels due to how the protein that transports serotonin is exposed.

What is a receptor and what is its role in serotonin deficiency?

There are two types of receptors: presynaptic and postsynaptic. Presynaptic receptors are designed to regulate the release of neurotransmitters from the synaptic cleft. The synaptic cleft is the space between neurons in which information is exchanged.

Postsynaptic receptors are designed to receive a signal from presynaptic receptors. If these receptors are not working properly or are insufficient, it can cause a decrease in serotonin levels.


Since serotonin affects many processes in the body, an insufficient amount of the neurotransmitter can lead to both psychological and physiological problems. Some of the symptoms associated with serotonin deficiency can be grouped into the following categories:

  • Psychological: anxiety and panic disorder, depression , aggression, poor impulse control, insomnia , irritability, low self-esteem, eating disorders, obsessive compulsive disorder ( OCD ).
  • Cognitive: poor memory fatigue
  • Physiological: Carbohydrate cravings, involuntary weight gain, nausea, digestive problems, poor appetite.

Low serotonin levels have also been linked to the development of certain chronic diseases such as Alzheimer's and Parkinson 's. The normal range for serotonin in the blood is about 101 to 283 nanograms per milliliter.

Watch out

Treatments for low serotonin levels may include:

  • Medications: Selective serotonin reuptake inhibitors (SSRIs) are a type of antidepressant prescribed to help the body make better use of serotonin. They prevent presynaptic receptors from taking over serotonin before postsynaptic receptors can bind to it. Medications can increase serotonin levels.
  • Light therapy: Light therapy is when people are often exposed to bright light. The light can be from the sun or from a light box. Research has shown that more light can increase serotonin levels in the brain.
  • Lifestyle changes: Lifestyle changes can help increase serotonin levels. When it comes to diet, research shows that eating foods high in tryptophan can cause an increase in serotonin. Regular exercise can also help increase serotonin levels. Aerobic exercise is especially helpful. Research has also shown that practicing meditation can help increase serotonin levels in the brain.

High serotonin

Serotonin levels that are too high can be dangerous. In some cases, high levels of serotonin in the blood may be due to a condition known as carcinoid syndrome . The syndrome is caused by a tumor that produces too much serotonin and can cause symptoms such as:

  • Redness or flushing of the skin
  • Facial skin lesions
  • Gastrointestinal problems such as frequent diarrhea and abdominal cramps.
  • Symptoms similar to asthma, such as wheezing.
  • Fast heartbeat
  • Dehydration
  • Soft spot
  • Muscle and joint pain

Another syndrome, known as serotonin syndrome , can occur if neurotransmitter levels become dangerously high.

Serotonin syndrome

Serotonin syndrome is characterized by markedly high levels of serotonin in the body. This can be life-threatening and requires urgent medical attention. Common causes of serotonin syndrome include:

  • Medications that increase serotonin levels, such as SSRIs.
  • Pain medication
  • Over-the-counter cold and cough medicines that contain dextromethorphan.
  • Migraine medications such as triptans.
  • Medicines used to treat the human immunodeficiency virus (HIV), which can cause AIDS.
  • Medicines for nausea, such as metoclopramide and ondansetron.
  • Supplements including ginseng and St. John's wort
  • Illegal drugs such as ecstasy, cocaine, or LSD.

People with serotonin syndrome often have a variety of symptoms that can be mild or severe. Mild symptoms can include:

  • Nervousness
  • Insomnia
  • Nausea
  • Diarrhea
  • Shaking
  • Late students

Moderate symptoms can include:

  • Hyperreflexia (hyperactive reflexes)
  • Perspiration
  • Emotion and anxiety
  • Inducible clonus (involuntary muscle contractions)
  • Side to side eye movements.

In severe cases, people may have a high fever, confusion or delirium, persistent clonus or stiffness, rhabdomyolysis (destruction of an injured muscle), or death.

If you experience any of the above symptoms and have recently started or increased the dose of a drug that can affect serotonin levels, seek medical attention immediately.

Watch out

People with serotonin syndrome will likely need to be hospitalized for at least 24 hours for follow-up. If the disease is mild and caused by a drug, simply stopping the drug or changing the dose can ease symptoms and restore normal serotonin levels.

Medications that stop the body's production of serotonin may be prescribed to relieve symptoms and prevent the condition from getting worse. Some commonly used medications during hospitalization include:

  • Benzodiazepines: used to reduce arousal, body shaking, and muscle stiffness.
  • Cyproheptadine: This type of medicine is used to block the production of serotonin.

Severe cases, as is often the case with serotonin syndrome, may require hospitalization for more than 24 hours so that the person can be closely monitored for changes or worsening of symptoms. Because serotonin syndrome can be life-threatening, you should seek medical attention as soon as possible.

While in the hospital, patients with serotonin syndrome may need to take medications to paralyze their muscles and may need a temporary breathing tube and breathing apparatus to prevent muscle damage.

How to Increase Serotonin Levels Naturally

If you have or suspect that you have low serotonin levels, there are ways to increase your serotonin levels naturally.


Since tryptophan is a precursor to serotonin, eating foods that are high in amino acids or that can help increase serotonin levels can help increase serotonin levels naturally. Eggs are one of the foods that can help raise tryptophan levels. Other foods that you can include in your diet include tofu, salmon, turkey, nuts and seeds, and cheese.

Increasing your carbohydrate intake can also increase tryptophan levels. Research has shown that increasing your carbohydrate intake while eating foods high in tryptophan can help tryptophan enter the brain more easily.


Several dietary supplements can help naturally restore normal serotonin levels, including:

  • Tryptophan Supplements – If you can't get enough tryptophan from your diet, there are supplements available to help increase your intake of this amino acid.
  • S-Adenosylmethionine This is a complementary version of a chemical compound that is found naturally in the body. It is used in the body in a process known as methylation, which is a chemical reaction that takes place in all cells of the body to promote proper function. Methylation is one of the last steps in the production of serotonin. For optimal serotonin production, there must be enough S-adenosylmethionine in the body.
  • 5-HTP – This is a complementary version of a natural amino acid found in your body.
  • Probiotics: Studies have shown that taking probiotics can help increase tryptophan levels in the blood.

Exposure to light

Exposure to light, also known as phototherapy, can improve serotonin levels and reduce symptoms of depression. Research has shown that exposure to sunlight can help the body synthesize serotonin through the skin.

The exercise

Proper exercise is important for overall health, but it can also naturally increase serotonin levels. Exercise triggers the release of tryptophan into the bloodstream, stimulating the production of serotonin. There are many types of exercise that can trigger this response, such as swimming, jogging, walking, or dancing.


Massage therapy has been shown to help increase serotonin levels while reducing levels of the stress hormone cortisol.

Frequently asked questions

How common is serotonin syndrome?

Although the prevalence of serotonin syndrome is unknown, a small study looked at the frequency with which patients experienced symptoms of the syndrome and found that approximately 7.8% of 309 intensive care unit (ICU) patients had some symptoms of the syndrome. serotonin syndrome. It is important to note that this is an atypical patient population.

When is serotonin released?

The release of serotonin can occur at different times of the day and during different activities. Some research suggests that serotonin can be released when the body begins to vomit to help eliminate bad foods from the body. Massage therapy has also been shown to induce the release of serotonin, in addition to helping you spend time in the sun or exercise.

Although there is little data on the time of day you experience the highest serotonin release, a study published in 2009 found that serotonin levels in rats given oral tryptophan were highest between 9:00 PM and 11:00 AM. p.m However, elevated serotonin levels may be due to elevated tryptophan levels.

How long does it take to replenish your serotonin supply?

There is no set time for serotonin levels to recover. This is because the chemical composition of the brain varies from person to person. In mild cases of serotonin deficiency, levels can be replenished quickly, while in others it may take longer.


Serotonin is a neurotransmitter that plays an important role in regulating mood, sleep, and the digestive system. High or low serotonin levels can cause problems. However, both can be treated with medication and lifestyle changes. There are also natural ways to increase serotonin levels.

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