What is serotonin?
Serotonin, also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter. It also acts as a hormone.
As a neurotransmitter, serotonin carries messages between nerve cells in the brain (central nervous system) and throughout the body (peripheral nervous system). These chemical messages tell your body how to function.
Serotonin plays a variety of roles in your body, including affecting learning, memory, well-being, and regulating body temperature, sleep, sexual behavior, and hunger. A lack of adequate serotonin is thought to lead to depression, anxiety, mania, and other health conditions.
Most of the serotonin found in your body is found in your gut. About 90% of serotonin is found in the cells lining the gastrointestinal tract. It is released into your blood circulation and absorbed by platelets. Only about 10% is produced in your brain.
Serotonin is made from the essential amino acid tryptophan. An essential amino acid means your body cannot make it. It has to be obtained from the food you eat.
What does serotonin do in my body?
Serotonin plays an important role in many functions of your body:
- Mood: Serotonin in the brain regulates your mood. It is often referred to as the body's natural "feel good" chemical. When serotonin is at normal levels, you feel more focused, emotionally stable, happier, and calmer. Low serotonin levels are associated with depression. Many medications used to treat anxiety, depression, and other mood disorders are often designed to increase serotonin levels in the brain.
- Digestion: Most of the body’s serotonin is found in the gastrointestinal tract, where it helps control bowel function and plays a protective role. Your gut can increase the release of serotonin, which speeds up digestion and clears your body of irritating foods or toxic products. Serotonin can also reduce appetite when eating.
- Nausea: When serotonin is released into the intestines faster than digestion can cause a feeling of nausea. The chemical message is received by your brain and you interpret it as nausea. Many medications used to reduce feelings of nausea and vomiting target specific serotonin receptors in the brain.
- Sleep: Serotonin, along with another neurotransmitter, dopamine, affects the quality of your sleep. Your brain also needs serotonin to produce melatonin, a hormone that regulates the sleep-wake cycle.
- Wound healing: Platelets in the blood release serotonin, which helps wounds heal. It also causes the tiniest blood vessels to narrow, which slows blood flow and contributes to the formation of blood clots. This is an important process in wound healing.
- Bone health: Serotonin levels may affect bone density. High levels of serotonin in the gut may cause bones to weaken, leading to fractures and osteoporosis.
- Sexual health: Serotonin, along with the neurotransmitter dopamine, also has an impact on sexual desire.
What problems are associated with low serotonin levels?
Low serotonin levels may be linked to many health conditions, including:
- Depression and other emotional problems.
- Sleep problems.
- Digestive problems.
- Suicidal behavior.
- Obsessive-compulsive disorder.
- Post-traumatic stress disorder.
- Panic Disorder.
Scientists still have a lot to learn about serotonin's role in the body and disease.
What causes low serotonin levels?
Low serotonin levels often have more than one cause. Technically, serotonin levels are low because:
- Your body cannot produce enough serotonin.
- Your body cannot use serotonin efficiently. This happens if you don't have enough serotonin receptors or the receptors aren't functioning properly.
What can I do to increase serotonin levels?
Ways to increase serotonin levels include:
- Eat more tryptophan-containing foods.
- Get more sunlight.
- Take certain supplements.
- Get more exercise and lower your stress levels.
Foods that increase serotonin levels
Many foods naturally contain tryptophan, the amino acid that produces serotonin. You can try to increase serotonin levels by eating foods containing tryptophan, such as:
- Nuts, oats and seeds
Eating tryptophan-rich foods by itself does not necessarily increase serotonin levels. This is a complex process. Your body needs carbohydrates to release insulin, which is needed to absorb amino acids. Even if tryptophan does enter your bloodstream, it must compete with other amino acids to be absorbed by your brain. Scientists are still studying how consuming tryptophan-containing foods might increase serotonin levels.
Not getting enough sun exposure may cause the mood disorder Seasonal Affective Disorder in some people. Try getting 10 to 15 minutes of sunlight each day to not only boost your serotonin levels, but also your vitamin D levels. If you live in an area without access to natural sunlight, consider using light therapy to get your daily dose of sunlight.
Some dietary and herbal supplements also increase serotonin levels. These include:
- Dietary supplements: tryptophan, probiotics.
- Herbal supplements: include ginseng, St. John's wort, Syrian rue and nutmeg.
Regular exercise is known to increase serotonin levels. Thirty minutes of aerobic exercise five times a week plus strength training twice a week can improve mood disorders and heart health.
What drugs increase serotonin levels?
Serotonin receptors are a common target for the pharmaceutical industry because many health conditions are affected by serotonin. Some common medications that increase serotonin levels include:
Several different classes of antidepressant drugs block the reabsorption and recycling of serotonin, allowing more serotonin to remain in the brain. Drugs that work in this way include selective serotonin reuptake inhibitors (such as paroxetine [Paxil®]), serotonin-norepinephrine reuptake inhibitors (such as venlafaxine [Effexor®]), and Tricyclic antidepressants (such as amitriptyline [Elavil®]). Another type of antidepressant medication is a monoamine oxidase inhibitor (such as phenelzine [Nardil®]), which blocks the enzyme that breaks down serotonin.
Many other drugs used to treat a variety of conditions also increase serotonin. Some of these medications include triptan headache medications, opioid pain relievers, cough suppressants containing dextromethorphan, and anti-nausea medications.
What problems can high serotonin levels cause?
Serotonin syndrome is a condition that occurs when serotonin levels rise too much. This usually occurs if you increase your dose of a drug known to increase serotonin levels or take another drug known to increase serotonin levels.
Mild symptoms include tremors, profuse sweating, confusion, restlessness, high blood pressure, muscle twitching and diarrhea. Severe symptoms include high fever, seizures, fainting and abnormal heartbeats.
If serotonin syndrome is severe and not detected early and treated quickly, it can be fatal.
What is the difference between dopamine and serotonin?
Dopamine and serotonin are both neurotransmitters. This means that they are carriers of chemical messages between nerve cells in the brain and between other areas of the body. Both are also considered "happy hormones" as they both play a role in positive moods and moods. Serotonin is associated with happiness, focus, and calmness. Dopamine is associated with reward and motivation. Dopamine and serotonin have also been linked to some mental health conditions, including depression and mood disorders.
Dopamine and serotonin also have some different functions. Dopamine controls body movement and coordination. Serotonin helps regulate digestive functions, including bowel function and appetite. Dopamine causes hunger, while serotonin suppresses this feeling. Dopamine is primarily stored in your brain, while serotonin is primarily stored in your gut.
Sometimes these neurotransmitters work together to maintain chemical balance in the body. Sometimes, an imbalance can lead to overproduction of another neurotransmitter. Too much or too little of any of these can lead to physical and psychological symptoms.
Serotonin plays a key role in body functions such as mood, sleep, appetite, anxiety, digestion, blood clotting, and libido. If you have a medical condition that affects or is affected by serotonin, ask your healthcare provider what you need to know about serotonin. To prevent fluctuations in serotonin levels in your body and reduce the possibility of drug interactions, do not stop taking your medications, change your dosage, or take dietary or herbal supplements without first talking with your healthcare provider.