The Gut-Serotonin Connection

Recent research continues to highlight the value of maintaining a healthy gut. As it turns out, our gut health is important for more than just digestion. The healthy microbes that inhabit our digestive system play a variety of roles in the human body. They impact our immune system, inflammation, metabolism, and more [1]. 

Serotonin, a neurotransmitter that plays a role in our mood, is produced primarily in the gut. This further exhibits the strong connection between our gut and our brain, known as the gut-brain axis (GBA) [2].

What is Serotonin?

Serotonin is a chemical neurotransmitter in the brain. It acts as a messenger to help control your brain’s functions along with mood. Researchers believe about 90-95% of the serotonin in your body is produced within your gut. The rest is produced in your brain [3, 4].

Serotonin is made from the amino acid tryptophan. This amino acid is commonly found in meat, most notably in that Thanksgiving turkey we enjoy once a year which makes us so sleepy. 

It can also be found in dairy products, eggs, and nuts.

Tryptophan is an essential amino acid, meaning we must obtain it from the foods we eat. If we do not consume enough foods that contain this amino acid, we risk suffering from low serotonin levels. An imbalance in our serotonin can result in physical and psychological challenges [4]. 

The Role of Serotonin in the Body

Serotonin provides many functions in the body but it’s mostly known for its ability to help stabilize mood. It’s sometimes referred to as the “feel good” chemical in the brain. Adequate serotonin levels are associated with improved mood and focus while low levels are associated with depression [4].

Serotonin is also responsible for regulating anxiety, improving wound healing, improving digestion, stimulating nausea in response to illness, regulating our sleep-wake cycle, regulating blood clotting, sexual desire, and more [5, 6, 7, 8].

Is More than 70 Percent of Serotonin Really Made in the Gut?

Research has found that upwards of 90-95% of serotonin is made in the cells of our digestive system. This makes our gut microbiome essential in creating a healthy amount of this chemical for our body [9].  

Serotonin is produced by a special type of immune cell known as Enterochromaffin (EC) cells. EC cells are the most abundant intestinal cells in the colon and are directly influenced by the gut microbiota [10].

What Happens if There is a Serotonin Imbalance?

Low levels of serotonin in the body are associated with mood disorders, such as anxiety, depression, difficulty sleeping, panic disorders, obsessive-compulsive disorders, and more. Low serotonin levels can happen in those whose body isn’t producing enough or isn’t effectively using serotonin.

High elevations of serotonin levels are rare and usually a result of medications used to increase serotonin levels. High serotonin can result in serotonin syndrome. This condition can be fatal if left untreated [4].

How to Optimize Gut Health for Serotonin Production

You can improve your serotonin levels by making a few lifestyle changes, including choosing more tryptophan-rich foods, increasing exposure to sunlight, taking certain supplements such as probiotics, and incorporating more physical activity [4].

Dietary Changes

Choosing more tryptophan-rich foods can help naturally boost serotonin levels. Tryptophan is found in many high protein foods such as poultry (turkey and chicken), fish, nuts (especially peanuts), seeds, milk, and tofu/soy products. 

You can also boost probiotic and prebiotic-rich foods to support a healthy gut microbiome. This will complement a diet rich in high tryptophan foods to ensure healthy serotonin levels. Incorporating more of these foods into your diet is an easy way to improve serotonin levels without the use of supplements. 

Exposure to Sunlight

Although most serotonin is produced in the gut, a small amount is produced in the brain. By getting enough exposure to sunlight, you can boost serotonin production. When you go outside on a sunny day, sunlight enters a part of your retina in your eye that signals your brain to produce serotonin [11].


If you struggle with gut health, adding a probiotic supplement to your routine may help boost serotonin. Researchers believe taking probiotics can increase the levels of free tryptophan in the GI tract. This can in turn increase serotonin availability. Speak with your doctor or healthcare provider before if you are thinking of adding a probiotic supplement to your routine [12].

Physical Activity

Like sunlight, exposure to physical activity can help boost serotonin production in the brain. This is because exercise naturally helps to regulate neurotransmitter levels. Exercise also boosts dopamine and norepinephrine in the brain, creating a happier and more regulated mood overall [13].

Lifestyle Habits to Maintain a Balanced Mood

Aside from ensuring you have adequate serotonin levels, there are many tips you can practice to help maintain a balanced mood. Certain lifestyle habits such as getting plenty of sleep, choosing a healthy diet, getting regular physical activity, reducing stress, maintaining a positive attitude, and finding a connection with others can all help to improve your mental health [14].

Although these may seem intuitive, it takes plenty of practice to incorporate these into your routine regularly. If you are just starting out with prioritizing some of these factors, it is best to focus on one at a time. Set small goals for yourself and only move forward once you feel you have successfully created a positive habit. 

To optimize gut health for better energy and mood, you can add some extra support with a comprehensive gut health supplement like Naked Gut. 

How to Promote Healthy Sleep

Sleep is essential for maintaining a healthy mood. Unfortunately, it is something that often gets put on the back burner when we get busy. Below are a few tips to help promote healthy sleep habits to ensure a good mood.

  1. Limit caffeinated beverages to only the morning time.
  2. Cut out screen time (television, phone, tablet, computer) at least 1 hour before bed.
  3. Incorporate more physical activity but avoid exercise right before bed.
  4. Set a regular bedtime and waketime each day to get your body into a schedule.
  5. Keep your room dark and quiet to promote a relaxing sleep environment.

Bottom Line

Serotonin is a chemical messenger that helps control your brain’s functions and mood. 90-95% of serotonin is produced by your gut. Serotonin also helps with anxiety, wound healing, digestion, and more. 

An imbalance in our serotonin can result in physical and psychological challenges, including depression. You can improve your serotonin levels by making a few lifestyle changes, like choosing more tryptophan-rich foods, increasing exposure to sunlight, taking probiotics, and incorporating more physical activity. 

Maintaining a well-regulated mood is essential for our mental well-being. Speak to your doctor if you suspect you may be struggling with low serotonin levels.