Serotonin: how does the “hormone of happiness” work and how to increase its level?


Serotonin is a chemical that acts as a neurotransmitter, transmitting signals from one area of ​​the brain to another. The chemical name of serotonin is 5-hydroxytryptamine or 5-HT. Being a neurotransmitter, it controls neural activity and is involved in a wide range of neuropsychological processes.

How does serotonin work in our brains?

Only 2 percent of all serotonin is in the brain. 95 percent of this substance is produced in the intestine, where it modulates hormonal, endocrine, autocrine and paracrine activity. In the brain, serotonin acts as a neurotransmitter, delivering signals to it to regulate motor function, the perception of pain and appetite. It also affects various biological processes, including the function of the cardiovascular system, energy balance, digestive function and mood control.

Serotonin is a byproduct of tryptophan, an amino acid that is known to naturally regulate mood and hormone balance.

Tryptophan is converted in the brain to serotonin and makes other essential amino acids available, helping to control mood and reduce the production of stress hormones.

Serotonin and Dopamine

What is the function of serotonin and dopamine? Both of these neurotransmitters have an effect on depression. Serotonin acts as a mood regulator, and also participates in many other processes of our body, for example, in digestion and sleep. Dopamine is associated with the so-called “pleasure center” in the brain. When we receive any kind of reward, dopamine rises. However, a low level of this neurotransmitter can lead to loss of motivation and good mood.

The main difference between serotonin and dopamine is how these neurotransmitters affect our mood. Dopamine is released after a pleasant experience and affects our interest and motivation, while serotonin affects how we perceive emotions. For optimal health, a balance of dopamine and serotonin is essential.

The effects of serotonin on mental health and depression

Serotonin transmits signals between nerve cells, making it possible to change brain functions that affect our mood and sleep. Also, in many clinical and preclinical studies, the effect of serotonin on depression is actively being studied. It is known that this substance signals many receptors in various areas of the human brain. However, the exact mechanisms of the antidepressant effects of serotonin are still being studied.

Studies by Columbia University researchers have shown that although 15 known serotonin receptors have been associated with depression and depressive behavior, the most studied are receptors 1A and 1B. Brain tomography and genetic studies have revealed that these two receptors are associated with depression and respond to antidepressant treatment. (1)

According to a review published in the journal World Psychiatry, “dysfunction of serotonin in some cases can lead to clinical depression.” Moreover, scientists believe that a decrease in serotonin function may jeopardize the patient’s ability to recover from depression, and not just lower the mood in vulnerable categories of people. This seems quite plausible, as studies have shown that tryptophan destruction is much more apparent in those who have had episodes of depression in the past (compared to those who simply have an increased risk of developing depression due to heredity). (2)

SSRI studies have shown that serotonin does not directly affect our mood, but rather stimulates positive changes in automatic emotional responses that help relieve symptoms of depression.

Useful properties and applications of serotonin

Improves mood and memory

Studies have shown that low serotonin levels are associated with poor memory and depressed mood. It is also known that serotonin and tryptophan cause changes in the intestine that affect the intestinal-brain connection, and therefore the mood and health of cognitive function. Researchers have been able to evaluate the effect of serotonin on depression by studying the effect of lowering tryptophan levels, which cause a decrease in serotonin levels in the brain. (3)

Regulates digestion

95 percent of all serotonin in the body is produced in the intestines. Studies have shown that this compound affects intestinal motility and inflammation. When released, 5-HT binds to specific receptors to initiate intestinal motility. In addition, serotonin helps regulate appetite, and also produces more chemicals that help to quickly remove foods that irritate the digestive system. (4)

Relieves pain

A study published in the journal Pain Research and Treatment found an inverse correlation between the strength of pain after surgery in patients with chronic lower back pain and serum serotonin levels. (5, 6)

Another study found that when healthy volunteers underwent acute depletion of tryptophan to manipulate 5-HT function, they experienced a significant reduction in pain threshold and tolerance to heat.

Improves blood coagulation

For blood coagulation, we need enough serotonin. This substance is released in platelets, helping with wound healing. In addition, it narrows the tiny arteries, forming blood clots. Despite the fact that such beneficial properties of serotonin contribute to wound healing, there is also evidence that an excess of this compound can lead to blood clots, one of the causes of coronary heart disease. For this reason, it is extremely important to maintain serotonin levels within the normal range, no more, no less. (7)

Promotes Wound Healing

A study published in the international journal International Journal of Molecular Sciences showed that serotonin is a potential drug to accelerate the healing process of burns. (8)

The researchers found that serotonin significantly accelerates cell migration, improving the healing process in cell culture and in a living model with burn lesions.

Norm of serotonin

You can check the level of serotonin by giving blood for analysis. For this purpose, blood from a vein is usually used. A similar analysis may be required for people with an increased risk of serotonin deficiency and carcinoid syndrome (high levels of serotonin). The norm of serotonin is 101–283 nanograms per milliliter (ng / ml). After receiving the test results, be sure to consult a doctor, since test values ​​may differ from what is considered to be the norm.

Symptoms and causes of serotonin deficiency

Studies have shown that dysfunction of serotonin is associated with mental disorders, including depression, anxiety disorders, compulsive behavior, aggression, substance abuse, seasonal affective disorder, bulimia, childhood hyperactivity, hypersexuality, mania, schizophrenia, as well as behavior disorders.

Symptoms of decreased serotonin include:

  • Depressed state
  • Anxiety
  • Panic attacks
  • Aggression
  • Irritability
  • Trouble sleeping
  • Appetite changes
  • Chronic pain
  • Memory problems
  • Digestion problems
  • Headache

What are the causes of low serotonin?

Serotonin is part of a complex system of chemicals and receptors. Low levels of serotonin may be associated with a lack of other neurotransmitters, which causes pronounced symptoms. Researchers cannot yet say with certainty what exactly causes serotonin deficiency.

It is believed that the cause may be heredity, malnutrition and lifestyle. Chronic stress and exposure to toxic substances such as heavy metals and pesticides increase the risk of serotonin deficiency. Other causes include a lack of sunlight and prolonged intake of certain medications.

Causes and treatment of serotonin syndrome

Serotonin syndrome (serotonin intoxication) occurs when a large amount of this substance is accumulated in the body. Sometimes the cause of this condition may be the simultaneous use of several drugs that increase the level of serotonin, or a combination of these drugs with certain herbal supplements. Drug use can also lead to this dangerous condition.

The most common symptom of serotonin syndrome is anxiety, anxiety, excessive agitation, increased sweating, and confusion. In more severe cases, this disease can also lead to muscle cramps, muscle stiffness, arrhythmias, high blood pressure, fever and convulsions.

Scientists also note that due to its effect on bones, elevated serotonin levels increase the risk of osteoporosis. If you notice these symptoms in yourself, be sure to consult a doctor and pass the necessary tests.

Treatment of serotonin syndrome involves the abandonment of drugs and drugs that caused an excessive increase in serotonin. Specialized drugs that block the production of this neurotransmitter, such as cyproheptadine, may also be prescribed.