A serotonin imbalance can contribute to depressed moods, irritability, poor sleep habits, cognitive dysfunction, low energy, headaches and hunger cravings. Serotonin is an important regulatory neurotransmitter, sometimes referred to as the “happiness hormone”.
Serotonin imbalance can occur when the body does not produce enough serotonin or it produces more than necessary for proper function. It may also be the result of dysregulation of serotonin metabolism or impaired function of serotonin receptors.
Serotonin is produced primarily in two locations in the body: the brain and the digestive tract (1). Roughly 90 percent of the hormone is produced in the digestive tract or gut, where it plays an important role in digestion and satiety signalling (2).
However, serotonin’s role in the brain receives more attention as a therapeutic target for mood disorders, depression, anxiety and more. Social behavior, pain sensitivity, overeating, restlessness, stress and angry or depressed moods may all be linked to the effects of a serotonin imbalance.



- Increases Serotonin levels in the brain
- Enhances mood and alleviates stress
- Improves sleep and regulates appetite
The Importance of Serotonin
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Serotonin is a naturally produced neurotransmitter and hormone in the human body.
It is an inhibitory neurotransmitter, meaning it helps to prevent the brain from being over-stimulated by other excitatory neurotransmitters, such as glutamate. This is important for maintaining mood balance and modulating signals sent between neurons.
In the gut, the serotonin is important for the process of digestion and moving food through the intestinal tract (3). It stimulates waves of muscle contractions in the walls of the intestines, which propels food forward in the gut, in a process known as peristalsis.
Serotonin is also important as the satiety hormone. It is used to signal to the brain where there is sufficient food to meet our needs, thereby inhibiting hunger craving. Serotonin is important for regulating appetite and preventing over-eating or binge eating. (4).
What is Serotonin Imbalance?
Serotonin imbalance refers to an unhealthy level of serotonin particularly in the brain, but also sometimes in the gut.
This can be brought about when normal levels of serotonin fall too high or too low, contributing to various health concerns. It can also occur when the function of serotonin is somehow impaired in the body.
Reduced serotonin levels may contribute to digestive health concerns, weight gain, osteoporosis and changes to mood and behavior (3). A high level of the hormone may result in serotonin syndrome. High levels in the gut may also be linked to irritable bowel syndrome and celiac disease.
There can be many different causes of a serotonin imbalance. Changes in dietary habits, taking a new medication or using psychotropic drugs, changes in your lifestyle and activity level as well as seasonal changes can all affect serotonin balance. (5)
Signs of Low Serotonin
Reduced serotonin levels contribute to mood changes, digestive health concerns, heart health concerns and osteoporosis (3). There has been some research showing that low serotonin may be associated with depression, but the link is not clearly understood.
Lack of serotonin in the brain may contribute to low moods, anxiety and other mood disorders, but it is not the only cause of these conditions (5). Depression and mood disorders are complex mental health conditions and multiple factors are likely to be involved.
Signs of reduced serotonin levels include: (4)
- Changes in mood, feeling depressed, stressed or anxious
- Increased appetite
- Poor sleep
- Increased sensitivity to pain
- Migraines and headaches
- Chronic constipation
If you think you may be experiencing symptoms of a serotonin deficiency imbalance, consult with a doctor to find out what the best treatment option for you is.
Dietary changes can be adopted to increase serotonin levels. Dietary supplements like 5-HTP and L-Tryptophan may also be used to assist with serotonin production in the brain (6).
Signs of High Serotonin
When levels of this chemical are too high in the brain or body, a condition known as Serotonin Syndrome or Serotonin Toxicity can result.
Excess levels of serotonin in the brain or of serotonin agonists can result in too much stimulation of 5-HT receptors. This can also cause serious adverse effects for your health and mood.
Serotonin syndrome is usually the result of combining multiple pharmaceutical agents that either mimic the effects of this neurotransmitter or stimulate its release in the brain. Consuming high doses of certain drugs and supplement may also increase the risk of developing excess serotonin imbalance symptoms.
Signs and symptoms of too much serotonin include:
- Headaches
- Changes in blood pressure
- General nausea or vomiting
- Increased heart rate
- Tremors
- Shivering or flu-like symptoms
- Weakness or muscle twitching
If you notice any signs of dangerously high serotonin levels, seek immediate medical attention. Excessively high levels of the hormone are potentially life threatening and may cause seizures, loss of consciousness or high fevers. (7)
Remedies for Serotonin Imbalance
If you feel that you are showing signs of a serotonin imbalance, consult with a doctor to determine the best treatment option.
Excessively high levels of serotonin require emergency care to prevent serious reactions. Low levels of this neurotransmitter do not typically require immediate care, but should still be discussed with a doctor.
Dietary changes and supplements may assist with helping to normalize your serotonin levels in the gut and brain.
L-Tryptophan is a natural amino acid found in foods that the body uses to make serotonin. Increasing your intake of foods that contain this nutrient or using supplements can boost low serotonin levels.
L-Tryptophan supplements are used to help with sleep apnea, athletic performance, PMS, depression and anxiety, smoking cessation and ADHD (7).
5-HTP is another supplement that you can use to help balance levels of this neurotransmitter. 5-HTP is an intermediary in the metabolism of L-tryptophan into serotonin.
This supplement is used for sleep disorders, mood disorders like depression and anxiety, headaches, binge eating disorders, PMS and fibromyalgia (6).
Of the two, 5-HTP is considered more effective for increasing serotonin levels in the short-term. L-Tryptophan does not have as significant an effect because it must first be converted into the byproduct 5-HTP, before it can be used to synthesize serotonin.
These supplements are considered safe when used appropriately, but they may interact with other medications or dietary supplements. If you are using anti-depressant drugs like selective serotonin reuptake inhibitors (SSRIs), consult with a doctor before taking these supplements as there is a risk for an interaction causing serotonin toxicity.
Both 5-HTP and L-tryptophan should be avoided during pregnancy or while breastfeeding, due to a lack of available research on safety for these groups.
There are many other ways that you can replenish normal levels of serotonin if you are seeing signs of a serotonin imbalance. Exercising, getting more exposure to sunlight, and consuming Vitamin D and Vitamin B6 can also help to correct low levels of this neurotransmitter.
- Jessica Stoller-Conrad, Microbes Help Produce Serotonin in Gut, Cal Tech, April 9, 2015, http://www.caltech.edu/news/microbes-help-produce-serotonin-gut-46495
- Serotonin: 9 Questions and Answers, Web MD, October 11, 2011, http://www.webmd.com/depression/features/serotonin
- Adam Hadhazy, Think Twice: How the Gut's 'Second Brain' Influences Mood and Wellbeing, Scientific American. February 12, 2010, http://www.scientificamerican.com/article/gut-second-brain/
- James McIntosh, Serotonin: Facts, What Does Serotonin Do?, Medical News Today, April 29, 2016, http://www.medicalnewstoday.com/articles/232248.php
- Dr. John M. Grohol, Psy.D., Low Serotonin Levels Don't Cause Depression, Psych Central, September, 2014, http://psychcentral.com/blog/archives/2014/09/13/low-serotonin-levels-dont-cause-depression/
- Natural Medicines, 5-HTP, August 26, 2015
- Joseph Goldberg, MD., What is Serotonin Syndrome, Web MD, November 18, 2014, http://www.webmd.com/depression/guide/serotonin-syndrome-causes-symptoms-treatments
- Natural Medicines, L-Tryptophan, November 3, 2015.
Article last updated on: March 12th, 2018 by Nootriment