Find a guide to the symptoms of serotonin deficiency and how to naturally increase levels.

Low Serotonin Symptoms and How to Naturally Boost Levels

Last modified on February 19th, 2023

Serotonin is a human brain chemical that helps carry messages between your brain and nerve cells throughout your body. Serotonin plays a role in many vital parts of our health and wellness, including digestion, mood, sleep, nausea, bone health, blood clotting, wound healing, and sexual desire. If you have levels that are too low or too high, it can cause mental and physical health problems.

If you’re experiencing low serotonin symptoms, you can naturally take steps to raise your levels, including certain supplements and so-called serotonin pills.

What is Serotonin?

Serotonin is also known as 5-hydroxytryptamine or 5-HT. Along with being a neurotransmitter, serotonin is also a hormone. Neurotransmitters are responsible for carrying messages between your central nervous system and your body, and the transmitted messages tell your body how it should work.

Most of the serotonin in your body is found in the gut; about 90% is in the lining of the GI tract. Serotonin is released into your blood, and your platelets absorb it. The brain produces only around 10% of your total serotonin or maybe even less. 

Serotonin is made from tryptophan, which is an essential amino acid. Your body can’t make essential amino acids; instead, you have to get them from the food you eat. Foods high in tryptophan include dairy products, meat, eggs, and nuts.

Serotonin affects every part of who you are and how you function, ranging from your emotions to your motor skills, and it’s thought to be a natural mood stabilizer that helps you experience happiness, regulate anxiety, heal wounds and stimulate nausea.

What Does Serotonin Do In My Body?

Specific things that serotonin plays a role in include:

  • Mood: The serotonin in your brain regulates your mood; you’ll sometimes hear it called your feel-good chemical. You will feel happier, calmer, more stable, and more focused if you have normal serotonin levels. When someone has low serotonin levels, it’s associated with depression. Many prescription medicines used for treating mood disorders like anxiety and depression target ways to increase serotonin in the brain.
  • Digestion: Since the bulk of your serotonin supply is in your GI tract, it also affects your bowel function. Your gut releases its serotonin levels to speed up digestion, which can affect how you experience feelings of hunger and appetite.
  • Nausea: If serotonin is released in your gut faster than you can digest, you experience nausea.
  • Sleep: Serotonin and dopamine affect how long and well you sleep. To produce melatonin, you also need serotonin. Melatonin is a hormone controlling your sleep-wake cycle.
  • Wound healing: Platelets release serotonin to help heal wounds.
  • Sexual health: Paired with dopamine, serotonin plays a role in your desire for sex.
  • Bone health: Serotonin levels may help your bones stay strong. However, too high levels in the gut can contribute to fractures and osteoporosis.

Some of the most interesting research on serotonin is the association between the gut-brain axis. While most estimates say around 90% of your serotonin is in your gut, other estimates put it as high as 95%, with just the other 5% being produced in the brain.

The gut-brain axis is the line of communication between your central and intestinal nervous systems.

Researchers are increasingly looking at how the serotonin produced in the GI tract moves through your body and regulates many important processes.

Symptoms of Low Serotonin

Some of the possible serotonin deficiency symptoms that a person might experience include the following:

  • Depression and similar mental health conditions
  • Sleep changes such as unusual sleep patterns or insomnia
  • Irritability
  • Chronic pain
  • Problems with memory or learning
  • Anxiety and obsessive-compulsive disorders
  • Schizophrenia
  • An altered internal clock
  • Appetite problems including eating disorders like not eating enough, overeating, or alternating between the two
  • Food cravings, especially for sugar
  • Obsessiveness or repetitive thoughts
  • Pessimism
  • Phobias or shyness
  • Social anxiety disorder
  • Suicidal behavior
  • Post-traumatic stress disorder
  • Seasonal affective disorder
  • Hyperactivity and attention-deficit hyperactivity disorder (ADHD)
  • Dementia

While we often think about the mental symptoms of low serotonin, there are a lot of potential physical consequences of a deficiency of the neurotransmitter.

Serotonin deficiency is associated with the following:

  • Fatigue
  • Gastrointestinal issues and digestive problems like irritable bowel syndrome
  • Obesity
  • Diabetes
  • Osteoporosis
  • Cardiovascular disease

If you think you have a serotonin deficiency, a doctor would rarely perform a test to check for it. There are serotonin blood tests, but these are usually only for checking tumors that produce serotonin.

A doctor won’t typically do a serotonin test because there are a lot of factors outside of your blood levels of the neurotransmitter that play a role in how you process and use it.

For example, your hormones, the behavior of your serotonin receptors, and your metabolism can all affect how your body processes and uses serotonin.

You could have normal blood levels but not much serotonin that’s accessible and usable.

Rather than checking your levels, a doctor will likely assess your symptoms and check those.

A lot of the medications most commonly prescribed for mental health disorders are believed to work by affecting how your brain uses serotonin, but this is becoming increasingly complex.

For example, there’s growing debate about the links between low serotonin and depression. It’s often very complicated when someone develops a mood disorder, and low serotonin levels may be one part of this.

Serotonin vs. Dopamine

We tend to talk about dopamine and serotonin because they work together but are very different neurotransmitters.

Dopamine is part of reward and motivation. If you experience, symptoms like helplessness or low motivation can be a sign of problems with your dopamine system.

Almost every pleasurable experience involves the release of dopamine.

Dopamine is unique from serotonin because it is produced mainly in the brain, while serotonin is primarily produced in the gut.

Dopamine affects pleasure and motivation, while serotonin serves as a stabilizer for your mood and anxiety.

Very few treatments and antidepressant medications target dopamine, it helps you feel more alert, while serotonin helps regulate your sleep and wakefulness cycles.

Unfortunately, some prescription medications for depression that target serotonin can negatively affect dopamine. In animal studies, SSRIs inhibit dopamine neurons, so some researchers theorize that taking these medications could suppress dopamine production.

The effects of SSRIs on dopamine may be why people experience sexual side effects and other side effects such as dulled emotions.

Why Are Serotonin Levels Important?

Serotonin levels are important because it influences your sense of happiness, learning, and memory.

Serotonin also helps regulate sexual behavior, hunger, sleep, and body temperature.

A lack of serotonin may play a role in anxiety, depression, mania, and many other health conditions. Low serotonin levels can negatively affect your quality of life.

What Can Cause Low Serotonin Levels?

While it’s not fully understood, some of the potential causes of serotonin deficiency include:

  • Chronic stress
  • Lack of natural light exposure
  • Genetic factors
  • Aging
  • Brain changes
  • Hormone changes
  • Nutritional deficiencies
  • Not eating a healthy diet
  • Certain drugs
  • Lack of physical activity
  • Chronic pain

Some research shows stressors early in your life could have a negative impact on you and the transport of serotonin throughout your body.

Other research points to the gut microbiome. You might have a disrupted gut microbiome because of disease, diet, stress, or many other factors that could influence your production of serotonin.

Your physical biology can affect your production of serotonin potentially too. This could mean that your body breaks down or absorbs serotonin too soon or you have fewer serotonin receptors. You could also have serotonin receptors that are less effective than what’s considered optimal or normal.

What Problems Are Associated with Low Serotonin?

Both physical and mental problems are associated with low serotonin, including depression, anxiety, insomnia, pain, sleep changes, and sexual behavior.

Natural Ways to Boost Low Serotonin

If your doctor believes you have low serotonin, they might prescribe certain medications.

One of the most widely used types of medication is selective serotonin reuptake inhibitors or SSRIs. These medications are antidepressants also used to treat anxiety. They help your body use available serotonin more efficiently but don’t create more serotonin.

Your body ultimately uses only part of the serotonin your brain releases. Some of the serotonin your body produces will go back into the cell where it came from, but SSRIs block some of this reabsorption of serotonin, so more is available for use. Reabsorption is also called reuptake.

SSRIs include Lexapro, Prozac, Zoloft, and Paxil.

There are also similar medications known as serotonin-norepinephrine reuptake inhibitors.

These medications can take weeks to start to have an effect, and they don’t work well for everyone. They can also have various side effects, which is why some people look to natural ways to increase their serotonin levels.

Foods That Raise Serotonin Levels

Since the bulk of your serotonin is made in the gut, it would make sense that the foods you eat can impact your levels significantly, with certain moods potentially improving mood.

Foods that increase serotonin include:

  • Poultry, such as turkey and chicken
  • Kefir, sauerkraut and other natural probiotics
  • Salmon and fish are excellent foods to increase serotonin
  • Eggs, especially when they’re poached
  • Soy products, tofu, and soy milk
  • Dairy products such as cheese and milk
  • Seeds and nuts
  • Pineapple, which contains tryptophan
  • Dark leafy green vegetables, like spinach, also help with the production of healthy red blood cells

Other Ways to Increase Serotonin Naturally

Along with thinking about your diet, other ways you can increase your levels of serotonin and lifestyle changes include:

  • Sunlight is good for increasing serotonin. People usually have lower serotonin levels during the winter because they get less sunlight. If you can spend 10-15 minutes in direct sunlight each day, it can stimulate the production of serotonin.
  • Regular exercise can boost serotonin.
  • Consider mood induction. Mood induction is a strategy where you create a positive mood by visualizing something that improves your mood or doing something you like.

The Best Supplements for Serotonin

Some supplements can potentially raise your levels of serotonin.


Probiotics can play a role in increasing serotonin and improving your mood. Certain probiotic strains might help with your mood and serotonin levels. One is B. longum, and another is L. Plantarum which may help raise dopamine levels.

Research finds that probiotics might improve mood and cognitive function and reduce anxiety and stress. Again, this makes sense since most of your serotonin production is happening in your gut.


S-Adenosylmethionine, or SAMe, is a compound found in nearly every fluid and tissue of our bodies.

It’s important for the immune system and helps produce and break down brain chemicals, including serotonin, dopamine, and melatonin—SAMe works along with B vitamins.

Some research shows that SAMe is more effective than placebos for treating mild-to-moderate depression and is as effective as antidepressants without side effects.

SAMe may also start working more quickly to improve mood than prescription antidepressants.


Tryptophan is an amino acid needed to produce serotonin.

Tryptophan, also known as L-tryptophan, is important for healthy brain function and sleep.

You can’t make tryptophan, so you have to get it from your diet or a supplement.

The amino acid is required for synthesizing serotonin, and it can also help with symptoms of anxiety, depression, ADHD, and more.

L tryptophan is a supplement that can naturally raise serotonin levels.

Vitamin B6

Vitamin B6 is also called pyridoxine, and it and other B vitamins are needed for the healthy production of neurotransmitters, including serotonin. B vitamins work along with tryptophan, helping convert it into functional serotonin. If you’re deficient in any B vitamins, it can negatively affect your production of serotonin.

Several studies show that restoring B vitamin levels can replenish your body’s serotonin and help with depressive symptoms and other mood disorders.

St. John’s Wort

St. John’s Wort is one of the most popular herbal supplements people use for depression.

It’s been long used in traditional medicine, dating back to the ancient Greeks.

St. John’s Wort, according to research, is more effective than a placebo and as effective as antidepressants for mild to moderate depression.

What About Serotonin Syndrome?

While everyone needs a sufficient amount of serotonin for physical and mental well-being, you can also have too much.

Serotonin syndrome is the name for levels that are too high. Serotonin syndrome can occur because of high doses of antidepressants or taking too many supplements that raise serotonin levels. If you combine medications with serotonin, like antidepressants and migraine medicine, serotonin syndrome can also occur.

Mild serotonin syndrome can include symptoms like diarrhea, while severe symptoms can include fever, seizures, and rigid muscles. Severe serotonin syndrome can be fatal if it’s not treated.

Final Thoughts

Serotonin is incredibly important. Serotonin works to keep your mood balanced, and having healthy levels is important for your physical and mental health.

Natural ways to increase your serotonin levels include eating certain foods to support serotonin production and taking supplements that may boost serotonin.

Medications increase serotonin levels and reduce depressive symptoms, but some people prefer a natural approach for various reasons.

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