Serotonin is this small molecule called a neurotransmitter which is released by a neuron and carries a very important message: that of happiness . If these messengers of happiness are released in sufficient numbers, they will then fight depression with good humor, a veritable army guaranteeing your emotional balance. But did you know that the power of serotonin is much more extensive than we think? Find out how to boost it so that the magic happens.
I. Serotonin: a neuronal messenger carrying positivity
1. Nature and role
Serotonin is a hormone found in neurons in the brain . It plays the role of neurotransmitter or neuromodulator . This means that this molecule is a chemical messenger responsible for communication between the different neurons for the proper diffusion of information .
2. Place of production and precursor
95% of our serotonin is secreted by the intestines and the rest by serotonergic neurons (in the middle part of the brainstem at the level of the raphe nuclei). When it is produced at the digestive level, it still ends up reaching the blood circulation , then the brain.
From this place of production, we quickly understand that food plays a key role in the production of this neurotransmitter , especially since its synthesis requires an amino acid present in food proteins : tryptophan .
3. Mechanism of action of the serotonergic system
Let's make an epistolary analogy to schematically explain the way in which serotonin fulfills its role as a messenger.
Step 1: Neuron 1 writes a message, for example "Stop depression, be happy", which it slips into an envelope.
Neuron 1 synthesizes serotonin which carries the message of happiness.
Step 2: Neuron 1 posts its letter in the mailbox which is then collected by the postman and transported to its recipient: neuron 2.
Neuron 1 secretes serotonin into the synaptic cleft (space between 2 neurons) which is transported by a specific transporter to neuron 2.
Step 3: Neuron 2 receives the message and takes note of the information that it will transmit to neuron 3 in the same way by creating a new mail.
Serotonin binds to a serotonin receptor present on neuron 2. The binding acts as an inhibitory nerve message for depression and stimulates the secretion of serotonin by neuron 2 into the synaptic space, which is transported and binds to neuron 3 .
Step 4: All the neurons communicate the information to each other by new mail until the entire neural network is aware. The brain then obeys the information and the general mood becomes positive.
Synaptic transmission (secretion, transport, fixation, message) thus takes place from one neuron to another until the entire neuronal network has the message. The brain then invaded by serotonin, the messenger of “happiness”, takes note of the information.
Step 5: Once neuron n+1 has received the letter, it returns to the sender (therefore to neuron n) because it has no interest in keeping the mail. He prefers to write a new one. He can also destroy the letter.
Once serotonin is fixed and the message transmitted to neuron n+1, the molecule is recaptured by neuron n which puts it back in reserve. The n+1 neuron can also degrade it and transform it into 5-hydroxyindole acetic acid (5-HIAA) which will be eliminated in the urine .
Note: The more letters the neuron posts, the better the message gets across, within the limit of a reasonable number of letters.
The more serotonin there is in the synaptic cleft, the more the message of “happiness” gets across.
4. The benefits
- Emotional balance: anti-depression, anti-anxiety, positive mood
We just repeat it in this article, serotonin is the happiness hormone . Its main and best known effect is on emotional balance with a reduction in depression and anxiety and an improvement in mood . Studies have also highlighted the link between low serotonin levels and mood disorders . It is not for nothing that treatments against depression act directly on serotonin : it is strongly involved. Indeed, anti-depression therapies involve selective serotonin reuptake inhibitors (or SSRIs ). This causes an increase in the brain quantity of the hormone and an increase in synaptic presence time. As a result, the body feels a feeling of fullness, consent and well-being.
- Regulation: emotionality, aggressiveness, suffering, behaviors
This neuromodulator , beyond emotionality , also regulates aggressiveness, the relationship to suffering ( aversion ) as well as behaviors (sexual, dietary, etc.) with an inhibitory effect.
Even if this is a bit of a caricature, we could almost say that this neurotransmitter plays on our personality traits.
It has also been shown that depending on the genetic coding of serotonin transporters and receptors, certain people are more predisposed to alcoholic disorders , anxiety disorders and antisocial behavior .
- Motivation, learning, decision making
In a study published in 2016*, 58 subjects were divided into 2 groups, one receiving an anti-depressant treatment based on SSRIs and the second a placebo treatment. The test consisted of squeezing a handle for a period of time. The longer the grip was held, the more money the subject earned. The conclusions were clear: patients receiving antidepressants made greater effort to obtain their reward . How to interpret this? Inhibition of serotonin reuptake increased its brain levels. The subjects treated were less aware of the importance of the effort required and the waiting time to receive the reward , which boosted their motivation . This same mechanism would also be at the origin of the benefits of serotonin on learning and decision -making.
This neurotransmitter therefore appears complementary to dopamine : it reduces the perception of the cost of the effort required to achieve the reward while dopamine enhances the expected benefit , both contributing to an improvement in motivation .
Serotonin will stimulate areas of the brain which control sleep and wakefulness and will therefore play a determining role.
With age , the serotonergic system functions less well, which contributes to changing behaviors (sleep, sexuality, mood). When we are young, we produce more serotonin and therefore we feel its benefits more.
- Cardiovascular system
This hormone is also present in blood vessels where it controls blood pressure by causing vasoconstriction or vasodilation depending on the receptors expressed on blood capillaries. It also plays a role in healing when it is released by blood platelets .
- Cancers (bladder, kidney, prostate)
An excess of serotonin and poorer regulation of its receptors stimulate the growth and progression of certain tumors . Conversely, at low doses , the effect is inhibitory by constricting the blood supply to the tumor . The effect is therefore dose dependent and this is what anti-tumor drugs work on. They are serotonergic receptor antagonists or secretion inhibitors .
II. Serotonin, the right dosage for optimal benefits
1. How to know your serotonin levels?
This hormone can be measured (via its degradation product 5-HIAA) in the blood , in the cerebrospinal fluid or in the urine , the last option being the most common. A normal level is between 3 and 10mg over 24 hours.
2. What are the consequences of serotonin deficiency?
When serotonin is lacking, it no longer exerts its trouble -inhibiting power and disinhibits the reflective control of behavior . The following are then felt:
- mood disorders, depression and behavior : emotionality, loss of pleasure, demotivation, impulsivity, irritability, aggressiveness, negative behavior, apathetic state, etc. A study showed that rats, which generally coexist without problems in a cage with mice, begin to attack them when their serotonin level is abnormally low . Another study showed that if you inactivate the gene that codes for serotonin receptors in mice, then they become particularly aggressive . In men, low levels of serotonin are generally associated with impulsive, aggressive, or even very violent behavior. In murder-suicide offenders, collapsed levels of 5-HIAA have been noted. Serotonin levels could even be used to predict possible future criminal or suicidal behavior in a problem child.
- concentration and learning problems
- sleep disorders : insomnia, nocturnal awakenings
- eating disorders : bulimia. A study was conducted on a rat that was given electric shocks while trying to get food. What have we observed? The lower the serotonin levels, the more the rat persists in wanting to eat despite the electric shocks
- sexual disorders : premature ejaculation, decreased libido. A study has shown that inactivation of the gene coding for serotonergic receptors in mice results in disinhibition of sexual activity .
This disinhibiting role is highlighted during the use of substances which reduce the neurotransmitter by interference (case of the aphrodisiac yohimbine) or by destruction of serotonergic nerve endings (case of ecstasy).
Actions are done more instinctively and are more dictated by impulses , without thinking about the consequences. These tendencies towards risky decision-making are particularly observed when the level of dietary tryptophan (precursor to serotonin ) is lowered.
3. As with everything, excess serotonin is harmful
An abundance of serotonin is often caused by taking an anti-depressant medication that excessively increases synaptic levels of the hormone . This surplus may be the cause of serotonin syndrome.
The symptoms are:
- Mild symptoms : nervousness, insomnia, nausea, diarrhea, tremor and dilated pupils
- Moderate symptoms : hyperreflexia (more pronounced reflexes), sweating, restlessness, feverishness, clonus (rhythmic muscle spasms), and ocular clonus (side-to-side eye movements).
- Serious symptoms : fever over 38.5°C, confusion, delirium, sustained clonus or even muscle rigidity, cancerous or non-cancerous tumors
However, most symptoms disappear quickly with serotonin -blocking medications.
III. 5 tips to boost your serotonin
- TIP #1: Expose yourself to sunlight. The link between sun exposure and blood levels of 5-HIAA in healthy volunteers has been demonstrated in several studies. In addition, post-mortem studies have shown that people who died in summer had higher serotonin levels than those who died in winter.
- TIP #2: Do sports (cycling, running, swimming, stairs, yoga, tai chi, etc.). In rats, it is scientifically proven that exercise induces an increase in the production of serotonin by neurons. In humans, physical activity increases 5-HIAA levels in depressed subjects. Moreover, sport has even become a treatment for depression in its own right through its ability to stimulate the activity of serotonergic neurons and to raise levels of tryptophan, its precursor.
- TIP #3: Consume foods containing the precursor of serotonin: tryptophan. Sources of tryptophan include: meat, poultry (turkey), salmon, spinach, dairy products, eggs, nuts (walnuts, cashews, almonds, peanuts) and soy beans, etc. for that. However, avoid meals that are too rich in protein because the different amino acids compete and are not all properly assimilated. So that the quantity of tryptophan provided is sufficient to stimulate the production of the happiness hormone, opt for a single-ingredient food supplement with only tryptophan or its immediate metabolite: 5-hydroxytryptophan (5-HTP) . Stay alert for contraindications, particularly with taking antidepressant medications, and consult a healthcare professional in all cases.
- TIP #4: Get a massage or meditate. This decreases levels of cortisol, the stress hormone. But stress causes serotonin levels to plummet. By reducing stress we increase our happiness neurotransmitter.
- TIP No. 5: Saffron in Life & Balance gummies. Saffron is the most effective natural way to inhibit serotonin reuptake. There are countless studies demonstrating its effectiveness on depression, anxiety and mood.
Happiness is chemical. It depends on a chemical molecule, serotonin, which plays the role of messenger within the brain. By naturally adjusting serotonin levels, it is possible to regulate your emotional balance to always see the glass half full.
*Meyniel F, Goodwin GM, Deakin JW, Klinge C, MacFadyen C, Milligan H, Mullings E, Pessiglione M, Gaillard R. A specific role for serotonin in overcoming effort cost. Elife. 2016 Nov 8;5:e17282. doi:10.7554/eLife.17282. PMID: 27824554; PMCID: PMC5100997.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5100997/