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Serotonin is probably the best-known neurotransmitter, the chemicals in the brain that carry messages between nerve cells. Most people remember serotonin as the “feel good” neurotransmitter, and many are taking a drug to keep it active longer in the brain. These drugs include selective serotonin reuptake inhibitors (SSRIs) or serotonin and norepinephrine reuptake inhibitors (SNRIs). Healthcare providers typically prescribe SSRIs to treat depression. But did you know your body produces serotonin? And did you know most of this feel-good neurotransmitter doesn’t come from the brain? 

What is Serotonin? 

Serotonin (5-hydroxytryptamine) is our “happy molecule,” a monoamine neurotransmitter made from the amino acid L-tryptophan. Scientists estimate that 95% of the body’s serotonin comes from the gut –made by the enterochromaffin cells in the gut lining. The gut microbes work together with these cells to regulate the production of serotonin and other signaling molecules that support the central nervous system (CNS).  

Over 10,000 nerve endings connect the gut to the brain. When we eat the right foods and can properly absorb nutrients, we can increase serotonin production in the gut. Healthy serotonin levels are associated with: 

  • Optimism 
  • Humor 
  • Positive social behavior 
  • Resilience when dealing with stress 
  • Cognitive flexibility 
  • Restorative sleep (as a precursor to melatonin) 
  • Overall feelings of well-being 

Serotonin plays a critical role in many functions in the body beyond mood. These include digestion, the immune response, the sleep-wake cycle, blood clotting, wound healing, bone development, and more. When the body is injured, platelets in the blood release serotonin to help stop bleeding and promote repair activities. 

Low serotonin, on the other hand, is commonly associated with negativity, mood disorders, feelings of overwhelm, poor cognition, and poor mental health. It’s also associated with other symptoms and health conditions – particularly brain-related ones. 

Low Serotonin Levels 

It’s widely believed that low serotonin levels affect your mental health. That’s why people seek out SSRI drugs like fluoxetine (Prozac), sertraline (Zoloft), and citalopram (Celexa) to help them feel better. However, it’s more complicated than that. Here are some symptoms and conditions associated with low serotonin levels:  

Signs, Symptoms, and Conditions  

Depression is probably the best-known condition associated with low serotonin. However, scientists in the neuroscience and psychiatry fields continue to debate the role of serotonin in depression. They aren’t confident of serotonin’s connection to depression at all.  

Psychology Today published a recent (July 2022) article with the headline, “Depression is Not Caused by Chemical Imbalance in The Brain.” A small study published in November 2022 did find decreased serotonin activity in depressed patients vs. a healthy control group. But correlation does not necessarily mean causation. 

The effectiveness of antidepressant medications is questionable, and they have plenty of harmful side effects. Learn more about how these medications came into use in this video with Dr. Jesse Anderson. 

What Depletes Serotonin? 

Low levels of serotonin can also come from production, uptake, or conversion issues, which go back to trauma, toxins, and thoughts. These three categories of stressors are the culprits behind chronic inflammation and all the imbalances that go along with it, including serotonin depletion: 

What Can Help? 

Because there are so many causes of low serotonin, testing for imbalances in the body is crucial. Once your Wellness Way practitioner has the testing results, they can help you address those imbalances and support proper serotonin synthesis and usage. Some of those strategies may include the following dietary and lifestyle changes:  

Chocolate can increase several neurotransmitters, including dopamine, phenylethylamine, oxytocin, and serotonin. Chocolate is one of the best foods on the planet for serotonin. So, don’t be afraid to indulge in organic dark chocolate as needed! 

High Serotonin Levels 

Believe it or not, it can also be a problem to have excessively high levels of serotonin. There’s a condition called “serotonin syndrome” or “serotonin toxicity.” As you may have guessed, this condition is caused by overmedicating with serotonin-promoting drugs. These include SSRIs, SNRIs, tricyclic antidepressants like amitriptyline, and even over-the-counter medications containing dextromethorphan like Delsym. ***This is also why it’s important to talk with your Wellness Way practitioner before starting any supplements like St. John’s Wort. 

Symptoms of serotonin syndrome may include nausea, vomiting, muscle spasms, heavy sweating, rapid changes in blood pressure, confusion, headaches, and occasionally even seizures. Severe serotonin syndrome can be life-threatening. 

Even though it may seem that more of this “happiness neurotransmitter” would be better, that’s not the case. In the human body, everything in the body needs a certain level of balance. 

Signs, Symptoms, and Conditions  

Signs and symptoms of high serotonin levels range from mild (nervousness, nausea, or diarrhea) to severe (fever of 101.3 F or higher, confusion, or delirium). They may include the following: 

  • Nervousness 
  • Dilated pupils  
  • Nausea 
  • Sweating 
  • Increased heart or breathing rate 
  • Tremors 
  • Rhythmic muscle spasms 
  • Feelings of agitation, excitement, or restlessness 
  • Confusion or delirium  

Too much serotonin can also alter the personality. It can make a person nervous, fearful, hesitant, distracted, prone to people-pleasing, and intolerant of criticism. It turns out that you can have too much of a good thing. Excessive serotonin will not make you feel happy.  

What Causes Elevated Serotonin? 

Would the body produce too much serotonin? No. Serotonin toxicity is most often pharmaceutical drug induced. Monoamine oxidase Inhibitors (MAOI) are the most likely to cause serotonin toxicity, followed by SSRI drugs. MAOI drugs prevent the breakdown of serotonin, and SSRIs focus on keeping it in the system longer. 

A few years ago, one of our Wellness Way doctors had this happen with a patient, a child diagnosed with ADHD. Inhibitory neurotransmitters like serotonin can be stimulatory if they are super high. In this case, test results showed this child’s serotonin levels were extremely elevated. The parents knew something was off. 

How did this happen? The child had been put on an SSRI (Selective Serotonin-Reuptake Inhibitor) medication, which was manipulating serotonin levels, making the child worse. So, the doctor advised the parents to take the results to their M.D. and show them that this medication was making things worse. 

What Can Help? 

Balancing out elevated serotonin levels requires knowing what medications may be causing this excess. Then a medical doctor or nurse practitioner can help wean the person off these medications. No matter what, it’s all about achieving healthy, balanced levels of neurotransmitters, which goes back to lowering inflammation levels and restoring overall health. 

Don’t Guess – Test! 

Many people turn to questionnaires or quizzes to find out their neurotransmitter levels. While doing so may give you some idea, it’s not accurate, and depending on which one you use, you could be completely off-base. At The Wellness Way, we can test your neurotransmitter levels – including your production, uptake, and conversion ability. We often begin with food allergy testing or stool testing, as imbalances in the gut greatly influence neurotransmitter activity. Once we have the results, we investigate where the problem is occurring and create a customized plan of action to help you get back to balance. Contact a Wellness Way Clinic today to start feeling like yourself again. 


  1. L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications – PMC ( 
  2. Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis – PubMed ( 
  3. Microsoft Word – braverman.test.doc ( 
  4. Serotonin in the gut: Blessing or a curse – ScienceDirect 
  5. Serotonin – an overview | ScienceDirect Topics 
  6. Attention deficit–hyperactivity disorder is associated with allergic symptoms and low levels of hemoglobin and serotonin | Scientific Reports ( 
  7. Depression Is Not Caused by Chemical Imbalance in the Brain | Psychology Today 
  8. New Research: Serotonin Does Have a Direct Role in Depression | Psychology Today 
  9. 3 Foods That Deplete Serotonin, From a Neuroscientist | Well+Good ( 
  10. Serotonin axons in the neocortex of the adult female mouse regrow after traumatic brain injury – PubMed ( 
  11. Mechanisms involved in the neurotoxic effects of environmental toxicants such as polychlorinated biphenyls and brominated flame retardants – PubMed ( 
  12. Copper induced oxidation of serotonin: analysis of products and toxicity – PubMed ( 
  13. Vitamin C in disease prevention and cure: an overview – PubMed ( 
  14. Vitamin D and the omega‐3 fatty acids control serotonin synthesis and action, part 2: relevance for ADHD, bipolar disorder, schizophrenia, and impulsive behavior – Patrick – 2015 – The FASEB Journal – Wiley Online Library 
  15. Stress, serotonin, and hippocampal neurogenesis in relation to depression and antidepressant effects – PubMed ( 
  16. The bowel and beyond: the enteric nervous system in neurological disorders – PMC ( 
  17. Mild serotonin syndrome: A report of 12 cases – PMC ( 
  18. Serotonin syndrome – Symptoms and causes – Mayo Clinic 
  19. Demystifying serotonin syndrome (or serotonin toxicity) – PMC ( 


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Disclaimer: This content is for educational purposes only. It’s not intended as a substitute for the advice provided by your Wellness Way clinic or personal physician, especially if currently taking prescription or over-the-counter medications. Pregnant women, in particular, should seek the advice of a physician before trying any herb or supplement listed on this website. Always speak with your individual clinic before adding any medication, herb, or nutritional supplement to your health protocol. Information and statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease.

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