Serotonin: What’s behind this happiness hormone?
4 min
©Oliver Rossi
The popular term “happiness hormone” is often used to refer to serotonin. But what exactly is it about this neurotransmitter that is largely regarded as a calming mood enhancer?
What is serotonin?
Serotonin, aka 5-hydroxytryptamine, is a hormone and neurotransmitter that is found in both the central nervous system and the cardiovascular, intestinal and blood systems. This may not sound so interesting at first glance – but if you take a closer look at the neurotransmitter, you are bound to feel optimistic.
Serotonin has a significant effect on our mood and is therefore popularly referred to as the ‘happiness’ or ‘feel-good’ hormone. It’s particularly important when it comes to the metabolism of our emotions and urges. When we have low levels of the substance, our mood drops.
And to what do we actually owe the production of this important neurotransmitter? As the Diagnostic Center (DCMS) explains1, serotonin is formed from the amino acid tryptophan, which reaches the brain through a transport channel in the blood-brain barrier. Serotonin, incidentally, is quite complex and diverse – and has different functions and effects in our body.
This is due in part to all the different receptors it binds to. According to current findings, there are at least 14 subtypes of 5-HT receptors.
Effect of serotonin: What roles does it play in the body?
Due to its complexity, this hormone has many different functions – and the best-known is surely its mood-boosting one. But it should be clear, the so-called happiness hormone is more than just a mood enhancer.
Serotonin has a significant influence on the generation of feelings such as balance, well-being and satisfaction. According to the Association for Independent Health Advice (UGB), depending on the receptor to which the neurotransmitter docks, it can have a calming effect, improve memory, or promote deep sleep2. In the gastrointestinal tract, serotonin is also involved in peristalsis, i.e. intestinal movements, while in the cardiovascular system it influences the contraction of blood vessels.
In general, we can think of serotonin as a messenger in our body whose task is to transmit information between nerve cells. It is also said to have a vasoconstrictive as well as a vasodilating and inhibitory effect – and to influence appetite, sex drive, drive, body temperature, and pain assessment, as well as our sleep-wake rhythms.
Serotonin levels: How they’re measured
Since serotonin is involved in so many functions of the body, a lack of the neurotransmitter can have a negative effect on the body and cause uncomfortable symptoms. In some cases, it might therefore be worthwhile to examine this issue.
Especially in cases of depressive moods, unexplained sadness, or anxiety disorders, one might want to take a test to measure their serotonin levels. These tests can also be taken at home, and one can use a test kit to fill a urine sample and send it to a laboratory for analysis.
However, the most common way is to go to your GP, who can diagnose a possible serotonin deficiency with a blood test. There is no hundred percent certainty, however, because such a test cannot determine the serotonin level in the brain.
Serotonin deficiency: Possible symptoms
For a long time, serotonin has played an important role in research. According to DCMS, a deficiency of this hormone is associated with feeling depressed. It should not, however, be automatically assumed that a depression implies low levels of serotonin.
Other possible psychological symptoms of a serotonin deficiency could be anxiety, increased aggressiveness, unprovoked mood swings, panic attacks, nervousness, exhaustion, and phobias.
Low serotonin levels can affect not only one’s mental health, but also affect the body. According to the DCMS, complaints such as headaches or muscle pain, a reduced feeling of satiety, concentration problems, sleep disorders, irritable bowel syndrome, high blood pressure, or cardiovascular disease can be common.
Serotonin in food
Serotonin is not only a phenomenon in humans – it is also said to be found in fruits and vegetables. This may sound promising, but hold off before you fill up your grocery list. Serotonin from food doesn’t make it to the receptors in the brain because the molecules are too big to cross the blood-brain barrier. So no matter how much of it you eat, it won’t get where you need it for lifting your spirits.
Any effect is therefore only slight, as graduate chemist Susanne Donner reports for the UGB. The expert further explains that a very specific amino acid, tryptophan, is also key. Tryptophan is also found in some foods and is known to be an important building material for the formation of serotonin. Foods that are rich in tryptophan include bananas, nuts, chocolate, mushrooms, fish, meat, soybeans, potatoes, eggs, as well as Parmesan, Brie, Edam, and Emmental cheeses.
However, there is no guarantee that food full of tryptophan will increase serotonin and provide you with lasting happiness. When or how quickly it starts to be formed depends on various factors such as physical activity and time of day. In addition, the tryptophan content in food is estimated to be too low to cause a strong effect at all.
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L-tryptophan: the serotonin precursor
L-tryptophan is widely known as a precursor of serotonin. Because this essential amino acid cannot be produced in our body itself, it must be consumed regularly. The World Health Organization (WHO) recommends an average daily dose of 3.5 to 5 milligrams per kilogram body weight for adults.
In addition, L-tryptophan has other functions in our body. For example, the amino acid is needed for part of the synthesis of Vitamin B3, as physician and pain researcher Dr. Tobias Weigl explains on his website3.
Due to its connection to serotonin, L-tryptophan is said to have a sleep-promoting effect as well as a mood-lightening, calming, and appetite-suppressing effect. In Germany, dietary supplements in capsule form with the amino acid added have been available on the market since 2014. According to the Federal Office of Consumer Protection and Food Safety, the recommended daily intake is one capsule. Don’t take more than 500 mg of L-tryptophan a day.
The amino acid is considered a natural antidepressant and could cause side effects or interactions, so it is essential to consult a doctor or therapist. The intake of food supplements containing L-tryptophan is not suitable for those who are pregnant or breastfeeding, children, or adolescents.
Serotonin: Summary
- In the human body, serotonin acts as a hormone and neurotransmitter.
- The neurotransmitter is formed from the amino acid L-tryptophan, which can be found in food or nutritional supplements.
- It is said to have a positive effect on mood and mental health.
- As a so-called happiness hormone, it promotes well-being and has a calming effect.
- This helpful hormone is also said to stimulate memory and promote sleep.
- Symptoms of low levels of serotonin could be bad mood, anxiety, or feelings of aggression.
- Anything you take in from food cannot reach the brain and therefore has little effect on your mood.
Sources for this article
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