Serotonin: Functions + Benefits + Ways To Boost The Levels

Written by , BSc, Professional Certificate in Food, Nutrition and Health Ravi Teja Tadimalla BSc, Professional Certificate in Food, Nutrition and Health Experience: 8 years
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Serotonin is a neurotransmitter produced by the nerve cells. It is also called the happy chemical – it regulates mood and may help alleviate depression. There are several other ways this hormone plays a beneficial role in your body. In this post, we’ll look into all of those – and a little more.

What Does Serotonin Do?

Serotonin (scientifically called 5-hydroxytryptamine) is derived from tryptophan, an essential amino acid. Tryptophan is commonly found in nuts, red meat, and cheese – and its deficiency is associated with several mood disorders.

Serotonin impacts almost every part of your body. It regulates your emotions and stabilizes your mood. This neurotransmitter also reduces depression and regulates anxiety (1).

It also has a role to play in bowel movements and sexual activity. It is a precursor to melatonin – a chemical that regulates the body’s sleep-wake cycle (2).

The several functions of serotonin in the human body throw light on its importance and other essential aspects. But before we get there, you must know more about the benefits of serotonin – in detail.

How Does Serotonin Benefit You?

As it is the happy chemical, serotonin helps induce happiness and may also reduce symptoms of depression and anxiety. Serotonin also boosts brain activity and sexual function.

1. Serotonin Induces Happiness

Studies show us that neurotransmitters, like serotonin, play a role in human happiness (3). Serotonin (and dopamine) regulates both positive and negative moods. In studies, this neurotransmitter mediated happiness, satisfaction, and optimism.

Further research also tells us that increased serotonin levels can be linked to a positive mood (4).

2. May Help Treat Depression And Anxiety

Researchers believe that imbalance in serotonin levels may influence mood, causing depression. Possible problems associated with depression can include low brain cell production of serotonin. However, it is not clear yet if low serotonin levels cause depression or if it is the other way round (5).

But there is a link between serotonin and depression. The neurotransmitter may influence the mood in depressed patients. Serotonin also may strengthen the communication between the brain’s cells – the lack of which causes depression (6).

In one animal study, mice with higher levels of serotonin in their brains exhibited reduced signs of depression and anxiety (7).

In another study, the use of SSRIs (Selective Serotonin Reuptake Inhibitors) had shown an improvement in depressive symptoms. SSRIs are medications that make serotonin more available in the brain (8). Patients with suicidal intentions were also found to have lower levels of serotonin.

3. Can Promote Better Sleep

Interestingly, serotonin has a role to play in both sleep and wakefulness. The neurotransmitter plays a role in the generation of REM sleep (9).

Accumulation of serotonin in a part of your brain called the dorsal raphe nucleus may put you to sleep (10).

Other studies also show that low serotonin levels may cause insomnia. When serotonin levels are brought back to normal, regular sleep falls back into place (11).

But excess serotonin levels may keep you up. The relation between serotonin and sleep is complex – and we need more concrete research to arrive at a conclusion (12).

4. Improves Brain Function

Optimal serotonin levels also boost cognitive functions. The neurotransmitter might also have some benefit for patients with Alzheimer’s disease, schizophrenia, and other cognitive issues (13).

Serotonin may have a role to play in human memory too (14). More studies are warranted before we can conclude this aspect.

5. Enhances Sexual Activity

One way serotonin may enhance sexual activity is by potentially relieving depression symptoms. Depression may thwart one’s sexual activity – and since serotonin may aid depression treatment, it can, as a consequence, boost sexual activity in patients (15).

Serotonin may also have desirable effects on male sexual function. The neurotransmitter increased erections and facilitated ejaculation in different instances (16).

6. May Promote Digestive Health

The circulating serotonin in the gut can determine predominant bowel function, as per reports (17). Serotonin levels in the gut go down during constipation, but they go up during instances of diarrhea or celiac disease.

Serotonin also influences gastrointestinal blood flow. It is also involved in multiple physiological processes of digestion (18).

Even the gut microflora can influence serotonin levels, and this may, in turn, impact the severity of certain gastrointestinal diseases (19).

Serotonin may play a role in promoting gastric emptying and relieving constipation (20).

Studies also show that serotonin can have both beneficial and detrimental effects on the gut (21). Hence, we recommend you talk to your doctor in this regard – especially before going for any form of serotonin supplements to treat your digestive issues.

7. May Help With Weight Loss

Studies show that depression may lead to weight gain – owing to the lack of interest on the affected individual’s part to indulge in healthy eating and physical exercise. As serotonin may relieve depressive symptoms, it may aid weight loss (22).

Serotonin may also activate certain neurons and help curb appetite. It also affects the brain’s melanocortin system, which is an important molecular pathway that controls body weight (23).

Certain serotonin drugs were also found to reduce the intake of high-fat foods in subjects. Activation of serotonin in the human system can also lead to selective avoidance of fat in the diet (24). These drugs are considered viable options to control the obesity epidemic in the future (25).

8. Helps Manage Pain

Serotonin plays a major role in modulating the perception of pain. Migraine headaches are often treated with serotonergic drugs – which also help in the management of chronic pain (26).

Even SSRIs seem to have desirable effects on chronic pain conditions (27).

9. May Aid Treatment Of OCD

Though we need more research, some studies show that SSRIs may help with the treatment of obsessive-compulsive disorder (28).

These benefits show us how crucial the neurotransmitter serotonin is. But, what if the serotonin levels go down? What would happen then?

What Happens When Serotonin Levels Are Low?

By low serotonin levels, we mean levels lower than 101 to 283 nanograms per liter (ng/ml) – which is the range for the optimal serotonin levels in the human body.

The exact serotonin levels differ from individual to individual – and may vary based on the samples tested and other measurements.

Low levels of serotonin can lead to serotonin deficiency, the symptoms of which include (29):

  • Depressed mood
  • Aggression
  • Anxiety
  • Irritability
  • Low self-esteem
  • Poor appetite
  • Poor memory
  • Impulsive behavior
  • Insomnia

Other physical symptoms of serotonin deficiency include:

  • Weight gain
  • Fatigue
  • Cravings for carbs
  • Nausea
  • Digestive motility issues (like irritable bowel syndrome and constipation)

The exact causes of serotonin deficiency haven’t been determined yet. But some potential causes may include the following:

  • Presence of fewer serotonin receptors in the body.
  • The existing serotonin receptors don’t receive serotonin effectively.
  • Serotonin could be getting broken down or absorbed way too soon.
  • Low levels of tryptophan, vitamins B6 and D, or omega-3 fatty acids that the body needs to produce serotonin.

Even your life experiences can play a role. Studies show that participants with a history of child abuse had lower serotonin levels when compared to those who weren’t abused (30).

But then, all this doesn’t have to spell bad news. Serotonin deficiency can be treated. This is where we talk about SSRIs, which are medical treatment options available to treat serotonin deficiency.

Selective serotonin reuptake inhibitors are antidepressant medications that enable your body to use serotonin more effectively. Some common SSRIs available in the market are:

  • Celexa
  • Prozac
  • Sarafem
  • Zoloft
  • Lexapro
  • Paxil

Do we have any natural methods as well? Scroll down to find out.

How To Naturally Increase Serotonin Levels?

  • Exercise: Exercise has been found to have antidepressant effects (31). Exercise improves mood – both in healthy and depressed individuals. Exercise is also found to boost brain serotonin function (32).
  • Exposure To Bright Light: Studies show that exposing yourself to bright light, either to the sun or a light box, might increase serotonin levels in your system (33).
  • Diet: Foods that boost tryptophan levels can contribute to optimal serotonin levels (32). These include eggs, salmon, tofu, cheese, pineapples, nuts, and turkey.
  • Mood Induction: Intentionally creating a happy mood or doing something you love can boost brain serotonin levels (32).

Treating serotonin deficiency is possible, and the results are encouraging. But with respect to medical treatments (like SSRIs), you need to know something.

A Note On Serotonin Syndrome

Also called serotonin toxicity, it happens when you take two SSRI drugs at the same time or when you take too many of the drugs. Hence, please be wary of the dosage and never take the drugs without medical supervision. Talk to your doctor.

Serotonin toxicity can cause the following symptoms, owing to excessive nerve activity (34):

  • Confusion
  • Restlessness and agitation
  • Diarrhea
  • Headaches
  • Increased blood pressure and heart rate
  • Shivering
  • Sweating
  • Loss of muscle coordination
  • Pupil dilation
  • Muscle rigidity

Severe serotonin toxicity can be life-threatening in some cases. But using just one drug in the dosage limits doesn’t usually result in serotonin toxicity (35).


Serotonin has a major role to play in several bodily processes. Becoming deficient in it is rare, but if it happens, please understand that you have treatment options. With the right changes to your lifestyle, you can get back on track once again!

Anything else you think we missed mentioning about serotonin? Why don’t you let us know by leaving a comment in the box below?


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Ravi Teja Tadimalla
Ravi Teja TadimallaSenior Editor
Ravi Teja Tadimalla is a senior editor and a published author. He has been in the digital media field for over eight years. He graduated from SRM University, Chennai, and has a Professional Certificate in Food, Nutrition & Research from Wageningen University.

Read full bio of Ravi Teja Tadimalla
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