Serotonin –Its Role in the Body, and What is Needed for its Normal Production

Serotonin, or the "happiness hormone," is a neurotransmitter that allows information to be transmitted between neurons and contributes to the feeling of well-being. It is mainly secreted by intestinal cells (95% of the body's serotonin comes from the intestine) and also by neurons present in the brain. It plays an important role in many physiological functions such as sleep, mood, eating, or sexual behavior.

Let's discuss this hormone of happiness, further explaining its role in the body and the causes and consequences of its deficiency!

Role of Serotonin in the Body

Serotonin is a chemical messenger synthesized by certain neurons from an amino acid, tryptophan, which accounts for a small part of the composition of dietary protein. It may work in the central nervous system by counteracting the effects of dopamine, another major neurotransmitter. Since its effects on mood are important, it is considered by some to be "the hormone of happiness"such as endorphins, dopamine and oxytocin. It is also involved in certain personality traits and the aging of an individual.

Serotonin-a Natural Antidepressant

In the brain, serotonin contributes to the feeling of well-being. In addition to influencing various physiological functions, it helps regulate mood, aggressiveness and emotionality. This is why most of the drugs used to treat depression (antidepressants) act on serotonin.

Thus, a serotonin deficiency can be involved in depression.A lack of serotonin can cause mood disorders and have physical consequences, such as premature ejaculation problems in men.

Serotonin and Aggressiveness, Impulsivity

Even if it is a bit of a caricature to assign a personality trait to a neurotransmitter, serotonin is involved in inhibition of aggression and aversion, and perhaps depression, or at least improved mood. The action of serotonin also moderates the effects of another neurotransmitter, dopamine.

In humans, abnormally low serotonin levels are generally associated with impulsive, aggressive, or even very violent behavior.

Collapsed 5-HIAA rates have been seen in people who murdered their families before trying to end their life. Researchers found that low serotonin levels in problem children were the best predictors of criminal or suicidal behavior.

Serotonin and Sleep

This chemical messenger is responsible for stimulating areas of the brain that control sleep and wakefulness. In other words, whether you are awake or sleeping depends on the area stimulated and the nature of the serotonin receptors used.

A Role in Aging

The serotonergic system works less well as we get older. This alteration could explain certain behavioral changes observed in the elderly regarding sleep, sexuality or mood. Serotonin could thus be potentially involved in the entire body's aging process via these links with various organs and the immune system in particular.

How to Calculate the Serotonin Level?

Blood, urine or cerebrospinal fluid are tested for the amount of 5-HIAA (5-hydroxy indole acetic acid), a breakdown product of serotonin, to assess its levels.

How Does the Serotonergic System Work?

After being released to transmit information, serotonin is re-captured by the neurons that have secreted it. It can also be degraded and transformed into 5-hydroxy indole acetic acid (5-HIAA), which will be excreted in the urine.

Almost all serotonergic neurons are found in the middle part of the brainstem (raphes nuclei). Their projections irrigate all areas of the central nervous system. Serotonin influences the activity of other neurons there, most often by reducing their frequency of discharge, inhibiting their action.

What Increases Serotonin?

Certain Drugs

Certain antidepressant drugs can increase the level of serotonin in the brain. But there are also natural ways, more or less proven, to increase its level, and which are sometimes used as a treatment for depression.

Physical Activity

Exercise also increases serotonin. The antidepressant effect of physical activity is well-proven, so much so that exercise has become a treatment for bad mood. And it could go through the action of serotonin.


Since serotonin is made from tryptophan, it seems logical that consuming foods that contain tryptophan can increase serotonin. This is why it is recommended to eat turkey, dairy products, eggs, nuts (walnuts, cashews, almonds, peanuts), soybeans, etc. When taken as a supplement, tryptophan seems to pass more easily into the brain.

We hope this information has helped you understand the role of Serotonin in the body and the causes of its deficiency. Do not forget to share this information with our friends and family, and let us know what you think about it!

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