What is Serotonin? Serotonin Functions, Ranges, Side Effects & More!
Medically Reviewed by Dr. Nicole Avena

Do you ever wonder what makes us feel happy?

One possible happiness generator is serotonin – the brain neurotransmitter responsible for mood regulation and overall well-being.

Let’s look at the science behind serotonin to learn more about its functions and importance in our moods and daily lives.

What Is Serotonin?

Serotonin is a chemical found in the human body that helps regulate mood and social behavior. While serotonin is best known for its importance in the brain, it’s also present in other parts of the body, including the blood, central nervous system, and gastrointestinal (GI) tract. In fact, most of the body’s serotonin is found in the gut, where it helps to regulate digestion.

So, how does serotonin work? When levels of serotonin are low, it can cause feelings of sadness or distress. But when levels are high, it can lead to mania or even psychosis. That’s why it’s important to have a balanced level of serotonin in your system.

Low serotonin can be caused by genetic factors, stress, or certain medical conditions. High levels of serotonin can be caused by certain medications or drugs.

Serotonin and the Brain

Serotonin Functions 2 Serotonin is involved in numerous brain functions, including mood, appetite, sleep, learning, and memory.

This neurotransmitter is produced in the brain by neurons. It’s then stored in synaptic vesicles, which are tiny sacs that store neurotransmitters. When a neuron is stimulated, the vesicles release their contents into the synaptic cleft, which is the space between neurons. The serotonin then binds to receptors on the next neuron and activates them. This process allows serotonin to relay messages from one neuron to another.

This chemical messenger is thought to help regulate mood and emotions. Low levels of serotonin can disrupt communication between neurons, and can lead to:

High/Low Serotonin

Serotonin levels can affect a person’s mood and well-being. Having too much or too little serotonin can come with side effects.

If there’s too much serotonin in the brain, it can lead to a condition called serotonin syndrome, which can be fatal. Symptoms of serotonin syndrome include high blood pressure, increased heart rate, sweating, agitation, confusion, and seizures.

Having too little serotonin in the brain can cause mood and sleep problems. Low serotonin also may lead to problems such as migraines and irritable bowel syndrome. For those with extremely high or low levels, a serotonin level test may be recommended.

Serotonin Level Test

The serotonin level test is usually conducted on individuals who may have carcinoid syndrome (a group of symptoms associated with carcinoid tumors). Those with carcinoid syndrome often have high levels of serotonin in the blood.

The serotonin level test can help determine the amount of serotonin in the blood. This simple procedure involves drawing blood from a vein, typically inside the elbow or on the back of the hand.

Ranges can vary from lab to lab, but normal serotonin levels are generally accepted to be between 50 to 200 ng/mL. Though there’s some debate over what’s considered normal, levels lower than 50 ng/mL may be an indication of potential mood problems. A higher-than-normal range may indicate carcinoid syndrome.

Be sure to consult with your healthcare provider before getting the serotonin level test to determine if it’s the right option for you.

Since the serotonin level test might not be necessary for everyone, other natural wellness interventions can be explored to help support your serotonin status and improve your daily health.

2 Ways to Support Healthy Levels of Serotonin

Healthy serotonin activity can be maintained in the brain and body by eating certain foods and supplementing your diet with nutrients that can help facilitate serotonin production.

Dietary Sources of Serotonin

You can find serotonin in some foods, but it’s also produced naturally by your body. Some dietary sources of serotonin include:

  • Nuts and Seeds: Almonds, walnuts, pumpkin seeds, and sunflower seeds are all good sources of tryptophan, an amino acid that’s converted into serotonin in the brain.
  • Eggs: Eggs are another good source of tryptophan. Eating eggs regularly can help increase serotonin levels.
  • Fish: Tuna, salmon, and halibut contain high levels of omega-3 fatty acids. These fats are essential for proper brain function and may help increase levels of serotonin.
  • Fruits and Vegetables: Fruits and vegetables contain vitamins and minerals that are necessary to produce serotonin. Dark leafy greens, bananas, oranges, berries, and tomatoes are all healthy choices.

Incorporating these foods into your diet may help increase serotonin levels, which may improve your mood and overall sense of well-being.

Serotonin Supplements

BrainMD’s Serotonin Mood Support was created specifically to promote multiple mechanisms that maintain healthy serotonin levels in the brain.* It can help increase the production of soothing brain waves, correct stress-related nutritional deficiencies, and promote relaxation that can facilitate quality sleep.*

This supplement contains essential nutrients and herbs that can help support serotonin production, such as vitamin B6, vitamin B12, folate and, 5-HTP, as well as a patented form of saffron.*

It’s always recommended to consult with your doctor or healthcare practitioner before beginning any supplement regimen.

Support Your Serotonin Functions

While serotonin plays an important role in regulating many bodily functions, it’s also a vital component for mental and emotional well-being.

When serotonin levels are balanced, you may experience an improved mood, higher energy levels, and better overall health.

Supporting serotonin – with diet, supplements, and other lifestyle measures – can help you maintain good physical and mental health over the long haul.


At BrainMD, we’re dedicated to providing the highest purity nutrients to improve your physical health and overall well-being. For more information about Serotonin Mood Support and our full list of brain healthy supplements, please visit us at BrainMD.

*These statements have not been evaluated by the FDA. This content is for informational purposes only. It is not meant to substitute for medical or healthcare advice from a physician, nor is it intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before beginning a new health regimen.

Keith Rowe