Serotonin: What You Need to Know

What does serotonin do?


  1. Serotonin is a natural mood stabilizer.
  2. Experts have linked low levels of it to depression.
  3. It can also help bodily functions, such as sleeping, eating, and digesting.

Serotonin impacts every part of your body, from your emotions to your motor skills. Serotonin is considered a natural mood stabilizer and the chemical that helps sleeping, eating, and digesting. Serotonin also helps reduce depression, regulate anxiety, heal wounds, stimulate nausea, and maintain bone health.

To learn more about these primary functions of serotonin, here are some more details:

  • Serotonin is found primarily in the body's stomach and intestines. It helps control your bowel movements and function. 
  • Serotonin in the brain is thought to regulate anxiety, happiness, and mood. Low levels of the chemical have been associated with depression, and increased serotonin levels brought on by medication are thought to decrease arousal. 
  • Serotonin is part of the reason why you become nauseous. Production of serotonin rises to push out noxious or upsetting food quicker in diarrhea. The chemical also increases in the blood, which stimulates the part of the brain that controls nausea. 
  • This chemical is responsible for stimulating the parts of the brain that control sleep and waking. Whether you sleep or are awake depends on what area is stimulated and which serotonin receptor is used.
  • Blood platelets release serotonin to help heal wounds. The serotonin causes tiny arteries to narrow, helping form blood clots.
  • Serotonin plays a role in bone health. Significantly high levels of serotonin in the bones can lead to osteoporosis, which makes the bones weaker.

Check out: IBS and serotonin: The brain-stomach link »


What is it?

What is serotonin?

Serotonin is a chemical nerve cells produce. This chemical sends signals between your nerve cells. Serotonin is found mostly in the digestive system, although it’s also in blood platelets and throughout the central nervous system.

Serotonin is converted from the essential amino acid tryptophan. This amino acid that must be enter your body through your diet and is commonly found in foods such as nuts, cheese, and red meat. Tryptophan deficiency can lead to lower serotonin levels. This can result in mood disorders, such as anxiety or depression.


Mental health

Serotonin, depression, and mental health

Serotonin helps regulate your mood naturally. When your serotonin levels are normal, you feel:

  • happier
  • calmer
  • more focused
  • less anxious
  • more emotionally stable

A 2007 study found that people with depression often have low levels of serotonin. Serotonin deficiency has also been linked to anxiety and insomnia.

A minor disagreement about the role serotonin plays in mental health has occurred. Some researchers in older studies have questioned whether an increase or decrease in serotonin can reduce or induce depression. Newer research has laid these concerns to rest. For example, a 2016 animal study found that mice lacking serotonin 1B, which is a receptor subtype of the chemical, exhibited less anxiety and depression-related behaviors.


Serotonin levels

What should your serotonin levels be at?

Generally, the normal range for serotonin levels in your blood is 101 to 283 nanograms/milliliter (ng/mL). This benchmark, however, may differ slightly depending on the measurements and samples tested, so talk to your doctor about specific test results.

High levels of serotonin may be a sign of carcinoid syndrome. This involves a group of symptoms related to tumors of the:

  • small intestine
  • appendix
  • colon
  • bronchial tubes

A doctor will take a blood test to measure serotonin levels in your blood to diagnose the disease or rule it out.

Low levels of serotonin in the brain may cause depression, anxiety, and sleep trouble. Many doctors will prescribe a selective serotonin reuptake inhibitor (SSRI) to treat depression. SSRIs are the most commonly prescribed type of antidepressant.

SSRIs increase the levels of serotonin in the brain by blocking the reabsorption of the chemical, so more remains to be active. SSRIs include Prozac and Zoloft, among others.

When on serotonin drugs, you shouldn’t use other medications without first talking to your doctor. Mixing drugs may put you at risk for serotonin syndrome.

Outside of SSRIs, the following factors have been found to boost serotonin levels:

  • exposure to bright light
  • exercise
  • a healthy diet
  • meditation

Serotonin syndrome

What is serotonin syndrome?

Drugs that cause your serotonin levels to climb and collect in your body can lead to serotonin syndrome. The syndrome presents itself typically after taking a new drug or increasing the dose of an existing medication.

The symptoms of serotonin syndrome include:

  • shivering
  • diarrhea
  • a headache
  • confusion
  • dilated pupils
  • goose bumps

Severe symptoms can include:

  • twitching muscles
  • a loss of muscle agility
  • muscle stiffness
  • a high fever
  • rapid heart rate
  • high blood pressure
  • an irregular heartbeat
  • seizures

There aren't any tests that can diagnose serotonin syndrome. Instead, your doctor will perform a physical exam to determine if you have serotonin syndrome.

Often, serotonin syndrome symptoms will disappear within a day by taking medication that blocks serotonin or by replacing the drug that's causing the condition in the first place.

Serotonin syndrome can be life-threatening if left untreated.



The bottom line

Serotonin affects every part of your body. It's responsible for many of the important functions that get us through the day. If your levels aren’t in balance, it can affect your mental, physical, and emotional well-being. Sometimes, a serotonin imbalance can mean something more serious. It's important to pay attention to your body and talk with your doctor about any concerns.

Keep reading: 7 Foods that could boost your serotonin »

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