Table of ContentsView AllTable of ContentsFunctionCauses of Low SerotoninHow to Increase SerotoninDangers of High Serotonin
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Table of Contents
Function
Causes of Low Serotonin
How to Increase Serotonin
Dangers of High Serotonin
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Serotonin is a naturally occurring monoamineneurotransmitterthat carries signals between nerve cells throughout your body. It plays an important role in various brain and body functions, including mood stabilization, cognition, learning, memory, and sleep.
Serotonin (also known as 5-hydroxytryptamine or 5-HT) is also considered a hormone. Most commonly, people are aware of serotonin’s role in thecentral nervous system(CNS).In the brain, serotonin helps with mood regulation andmemory, but it also has essential jobs in other areas of the body.
Most of the serotonin in your body is actually found in yourgut, not your brain. The intestines produce almost all of the body’s serotonin supply, and serotonin is required to promote healthy digestion.
Elsewhere in the body, serotonin helps with sleep, sexual function, bone health, and blood clotting.Here’s a closer look at serotonin’s many functions, what happens if you have too little (or too much), and a few ways to balance your levels for optimum health.
What Exactly Does Serotonin Do?
Serotonin is known to be involved in many bodily functions, ranging from regulating mood to digesting food.
Mood
Serotonin’s effects on the brain could be considered its starring role in the body. As it helps regulate mood, serotonin is often called the body’s natural “feel-good” chemical because it makes us feel happy and calm at normal levels.Serotonin’s influence on mood makes it one of several brain chemicals that are integral to your overallsense of well-being.
Serotonin’s effect on mood is also why it’s often a target of medications that are used to treat depression, anxiety, and other mood disorders.For example, increasing serotonin levels is the purpose of theclass of antidepressantsknown as selective serotonin reuptake inhibitors (SSRIs).
The Chemistry of Depression
Digestion
Serotonin contributes to normal bowel function and reduces your appetite as you eat to help you know when you’re full. It also plays a protective role in the gut.
The response is also why increased levels of serotonin can make you nauseated, and why drugs that target specific serotonin receptors can be used to alleviate nausea and vomiting.
Sleep
The exact nature of serotonin’s role in sleep is still being studied, but it’s believed to influence when, how much, and how well you sleep.Serotonin does not regulate these tasks alone; other neurotransmitters like dopamine also play a key role.
A hormone called melatonin is also critical to the proper functioning of the sleep cycle.Your body needs serotonin to make melatonin, so not having enough serotonin (or having too much of it) can affect the pattern and quality of your sleep.
The serotonin-melatonin relationship might also contribute tosleep disruptionslike insomnia, which are common in people with depression.
Your brain has specific areas that control when you fall asleep, regulate your sleep patterns, and wake you up. The parts of your brain that are responsible for regulating sleep also have serotonin receptors.
In the case of serotonin vs. dopamine, for instance, serotonin can either help you fall asleep or keep you from sleeping, depending on where it is released in the brain. Dopamine will keep you awake.
How Sleep Affects Your Mental Health
Blood Clotting
When you have any kind of tissue damage, such as a cut, the platelet cells in your blood release serotonin to help heal the wound.Increased serotonin levels cause the tiny arteries (known as arterioles) of the circulatory system to narrow. As they get smaller, blood flow slows.
This narrowing (known as vasoconstriction) and slowed blood flow are two important elements of blood clotting—a crucial step in the process of wound healing.
Bone Density
Studies have shown that serotonin levels may influence bone density (the strength of your bones). Research suggests that high circulating levels of serotonin in the gut might be associated with lower bone density and conditions like osteoporosis.
Research suggests that SSRI medications are associated with decreased bone mineral density.Low bone density puts you at a greater risk for fractures.
Sexual Function
In addition to altering mood, serotonin can also influence the frequency and intensity of sexual feelings.
Certain antidepressants that increase serotonin levels can havean effect on libido, as elevated serotonin levels have been associated with a decrease in sexual desire.
Serotonin’s influence on libido is also somewhat related to its relationship to dopamine. For example, a 2017 study of women with hypoactive sexual desire disorder (HSDD) found that symptoms of the condition were associated with increased serotonin activity and reduced dopamine activity.
How Psychologists Define Libido
Depression and other mood disorders that are linked to serotonin are multifactorial, meaning there is more than one reason they occur. Having low serotonin levels is not, on its own, enough tocause depression.Low levels can, however, contribute to mood, sleep, and digestive problems, and other issues.
There’s no single cause of low serotonin levels, but it typically occurs for one of two reasons: not having enough serotonin or inefficient use of the serotonin you have. In the first scenario, you have low levels of serotonin because your body is not producing enough to maintain normal levels.
Your body might not be able to produce enough serotonin because of other factors, such as nutritional and vitamin deficiencies.
For example, low levels of vitamin B6 and vitamin D have both been linked to decreased levels of serotonin. Tryptophan, an essential amino acid involved in serotonin production, can only be obtained through diet.
The other reason you might have a serotonin deficiency is that while your body is making serotonin, it is not using it effectively. This can happen if you don’t have enough serotonin receptors in your brain, or if the ones you have don’t work well (for example, they absorb and break down serotonin too quickly).
Signs of Low Serotonin
How do you know if your serotonin levels may be low? Signs of a potential serotonin deficiency include:
Studies also suggest that serotonin levels may decrease with age, potentially due to a decline in the function of serotonin receptors and transporters.
Verywell / Madelyn Goodnight
Depression is known to be associated with chemical imbalances in the brain. While serotonin’s role in depression is more complex than an imbalance, it is believed to play a key role.
Increasing how much serotonin is in the brain appears to improve communication between brain cells, which in turn lifts mood and reducessymptoms of depression. This is why prescription antidepressant medications are used to treat clinical depression and other mood disorders.
There are also natural ways to increase serotonin levels. Everything from the food you eat to how much sunlight you get can affect how much serotonin your body has, as well as how effectively it can use it—both of which can help correct a serotonin deficiency.
How to Stimulate Serotonin
Selective Serotonin Reuptake Inhibitors (SSRIs)
When brain cells send signals to one another, they release neurotransmitters, including serotonin. Before they can send the next signal, the cells must reabsorb and recycle the neurotransmitters they have released. This process is calledreuptake.
Examples of SSRIs that are commonly prescribed to treat depression and other mood disorders include:
Medications such asViibryd(vilazodone) are not only an SSRI but also a 5HT-1a partial agonist.Drugs in this class are not solely classified as SSRIs, but rather, as serotonergic antidepressants. Trintellix (vortioxetine) is a similar drug.
Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)
Another group of serotonin-based medications for treating depression is known as serotonin-norepinephrine reuptake inhibitors (SNRIs). These drugs work similarly to SSRIs in that they block the reuptake of serotonin, but they also work onnorepinephrine, another neurotransmitter that affects mood.
Drugs that act on both serotonin and norepinephrine are sometimes referred to as “dual-acting antidepressants.”
Popular SNRIs include:
Tricyclics (TCAs) and Monoamine Oxidase Inhibitors (MAOIs)
Two older classes of antidepressants also affect serotonin levels:tricyclic antidepressants(TCAs) andmonoamine oxidase inhibitors(MAOIs).
TCAs appear to block the reabsorption of serotonin and norepinephrine, which effectively increases the amounts available in the brain.
Examples of TCAs include:
MAOIs block the effects of the monoamine oxidase enzyme, which breaks down serotonin, epinephrine, and dopamine.Preventing these neurotransmitters from being broken down effectively increases the amounts available in the brain.
Examples of MAOIs include:
TCAs and MAOIs are not prescribed as often as other antidepressants because they tend to have moreside effectsthan SSRIs and SNRIs.
Food
Many foods naturally contain serotonin, but your body also needs other nutrients, such as tryptophan, vitamin B6, vitamin D, and omega-3 fatty acids, to produce serotonin.
Foods that are good sources of these key nutrients include:
Eating a high-fiber diet that is rich in fruits and vegetables will help keep your gut bacteria healthy. Having a good balance of friendly bacteria in your intestines has been linked to adequate serotonin levels (as the intestines make about 95% of your body’s supply).
Foods to Help Fight Depression
Exercise
Regular physical activity (especially aerobic exercise) has been proven toboost serotonin levels.However, the benefits of regular exercise go beyond your brain.
The Department of Health and Human Services recommends that adults get at least 150 minutes of moderate-intensity cardio exercise each week plus strength training two days per week.
Talk to your healthcare provider before starting an exercise routine. Be sure to pick activities that you enjoy, as you’ll be more apt to stick with them, and consistency is key to getting all the benefits.
Best Forms of Exercise to Improve Mood
Light Exposure
Your levels of serotonin might get low if you don’t get out in the sun regularly. Not getting enough exposure to sunlight is one theory behind why people experience depression during the short, dark days of fall and winter (a mood disorder calledseasonal affective disorder).
Try to spend 10 to 15 minutes outside in the sun each day. Sunlight also boosts your levels of vitamin D, which is needed for serotonin production.
If you live in a place with little to no sunlight, you can also uselight therapyto make sure you’re getting your daily dose of sunshine.
Massage
Massage therapy has been found to promote the release of serotonin and decrease the stress hormonecortisol, making it an appealing non-pharmaceutical addition to depression and anxiety treatment plans. You don’t even need a professional massage to reap the benefits.
Supplements
Before taking any supplement, even those that are over-the-counter, speak to your healthcare provider (as some of these can interact with other medications and/or may not be indicated given someone’s medical history).
While you can improve your overall nutrition through your diet, certain supplements may also be helpful.Popular dietary supplements you might want to consider include:
Over-the-Counter Antidepressants
What Happens When Serotonin Is High?
Certain medications and supplements can raise serotonin levels too much, which can lead toserotonin syndrome.
Serotonin syndrome is a condition resulting from elevated serotonin levels, It often occurs when someone is first taking a new drug that affects serotonin, or if the dosage of a current drug is increased.
The symptoms of serotonin syndrome range from unpleasant to life-threatening and can include sudden swings in blood pressure, seizures, and loss of consciousness. Too much serotonin can also cause an increase in anxiety or nervousness. Always ask your healthcare provider before taking any medication or supplement toincrease low serotonin.
Serious cases of serotonin syndrome can be fatal if left untreated. If you or a loved one is showing symptoms of serotonin syndrome,call 911or go to the nearest emergency room.
Summary
When your body doesn’t have enough serotonin, or if it isn’t using the serotonin you have effectively, you might bemore prone to symptoms of depressionand other mood disorders. And while low levels of serotonin can cause problems, having too much serotonin can also be an issue.
If you’re concerned about the symptoms you’re experiencing, talk to your healthcare provider. If your serotonin levels are a culprit, you are not alone and there are many treatment options available, including both medications and lifestyle changes.
The Evidence Is In: Depression Might Not Be Linked to Low Serotonin After All
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