Serotonin Deficiency: What to Know

Serotonin deficiency is linked to pain, fatigue, depression, and more

Serotonin is a neurotransmitter, a chemical messenger that helps with regulating mood. It sometimes acts like a hormone as well. When your body doesn't produce enough serotonin or its receptors don't work well, the resulting serotonin deficiency can impact your physical and emotional health. When serotonin is low, symptoms include:

  • Depression
  • Negative thoughts
  • Anxiety
  • Irritability
  • Low energy
  • Fatigue
  • Memory problems
  • Changes in sleep patterns
  • Chronic pain
  • Changes in appetite
  • Binge eating
  • Loss of interest in sex

This article goes over what serotonin does, the range of possible low-serotonin symptoms, how low serotonin is diagnosed, and what you can do to boost your levels, if needed.

Sad woman suffering from insomnia while sitting on her bed
demaerre / Getty Images

What Does Serotonin Do for the Body?

Serotonin is a regulator of many processes in the body. When serotonin levels are out of balance, so are the processes and functions to which they contribute.

Serotonin's dual nature as a neurotransmitter and hormone means that it's found throughout your body. Perhaps surprisingly, there's more serotonin in your gut than in your brain. The effects of low serotonin are many and seemingly unrelated symptoms may, in fact, be related to it.

Take fibromyalgia (FMS) and chronic fatigue syndrome (CFS or ME/CFS), for example. Both may be linked to serotonin deficiency. Irritable bowel syndrome (IBS) also involves serotonin dysregulation and is extremely common in those with either of these conditions.

Learning to spot the signs of low serotonin can help you get a diagnosis and treatment.

Serotonin Deficiency and Long COVID

New research on COVID-19 infection suggests that low serotonin levels may play a role in long COVID cases. The study suggests that medications used to treat people with low serotonin levels may show promise in offering benefits to those living with long COVID.

What Are the Symptoms of Serotonin Deficiency?

Low serotonin levels can lead to both physical and emotional changes. The low serotonin may be due to the amount of serotonin produced, or the proper function and availability of serotonin receptors to use it in the body. Other causes may include the effects of nutrients like vitamin D.

Whatever the reason, serotonin deficiency can cause people to experience a range of symptoms.

Emotional Symptoms

Emotional symptoms associated with low serotonin include:

  • Social withdrawal
  • Sadness and frequent crying spells
  • Low self-esteem and self-confidence
  • Changes in personality
  • Feeling emotionally sensitive and taking things personally
  • Irritability

Aggression (hostile action) has long been a symptom suspected of being linked to low serotonin levels. Research indicates that anger as a feeling may be one as well but future study is needed.

Talk to your healthcare provider about any of these symptoms of low serotonin.

The presence of emotional symptoms does not confirm a mental health issue. However, serotonin is involved in certain mental illnesses, such as major depressive disorder. Low serotonin also has been noted in people with obsessive-compulsive disorder (OCD), but research has yet to confirm a causal connection.

Physical Symptoms

Some of the physical symptoms linked to low serotonin include:

  • Chronic fatigue even though you get adequate rest
  • Disturbed sleep
  • Loss of appetite or carb cravings (possibly from the body's attempt to make more serotonin)
  • Hot flashes and temperature changes that are not linked to your environment
  • Headaches
  • Stomach pains

Certainly, some of these symptoms can crop up in anyone's life from time to time. The key is to recognize whether you have clusters of symptoms that tend to occur together.

Serotonin levels can fluctuate, leading to symptom flares and remissions (times when symptoms are gone or at low levels).

Low Serotonin and Dizziness

Declining serotonin levels can cause dizziness. This may be because the vestibular system, which preserves a sense of balance, has many serotonin receptors—structures that allow messages from serotonin to be received. Dizziness also is a common side effect of SSRI drugs.

Related Health Conditions

Certain health conditions are associated with low serotonin levels. They include:

Much of the research on serotonin is done in animals, with results that suggest serotonin may play a role in other conditions and functions including sleep, breathing, and more.

Serotonin and Cancer

Some studies suggest that serotonin levels can affect the growth of tumors in lung cancer, melanoma, and colorectal cancer. It also appears to act on the immune system. Researchers are exploring how selective serotonin reuptake inhibitors (SSRIs) might be used to treat cancers.

What Causes Serotonin Deficiency?

Low serotonin levels may have a number of causes, many of which are still under study. Tryptophan levels play a role, because your body cannot produce serotonin without this amino acid. So do omega-3 fatty acids. Animal studies suggest vitamin B6 may also play a role in some cases.

Other research points to the role of genetics or environmental factors that can lead to disruptions in serotonin levels.

Low serotonin can happen because your body does not make enough or it does not use it efficiently. There are likely several factors that cause or contribute to this. These may include genetics, stress, chronic pain, and nutritional deficiencies.

How Do I Know if My Serotonin Levels Are Low?

Measuring neurotransmitters is not a reliable way to diagnose low serotonin, so you can't simply check your serotonin levels. Instead, healthcare providers rely on a review of your symptoms to make a diagnosis.

If you have physical and emotional symptoms that you think could be from low serotonin, it’s important to reach out to your primary care provider or a mental health provider for an evaluation.

Getting Help

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 1-800-273-8255 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911 without delay.

For more mental health resources, see our National Helpline Database.

How Is Serotonin Deficiency Treated?

There are many ways that low serotonin can be fixed. Some people find that a combination of strategies works best for raising their serotonin levels and keeping them in a range that supports their physical and mental health. 

For example, managing stress levels and seeking support from friends can work alongside of medication used to treat depression. Here are some of the strategies for treating serotonin deficiency.

Antidepressant Medication

Antidepressant medications like SSRIs, SNRIs, MAOIs, and tricyclics can treat low serotonin. Your provider may prescribe one to you. Know, however, that these drugs can take some time to work.

Common SSRIs include:

  • Celexa (citalopram)
  • Lexapro (escitalopram)
  • Paxil, Paxil CR, Pexeva (paroxetine)
  • Prozac (fluoxetine)
  • Zoloft (sertraline)

Nutritious Diet

Eating a nutritious diet can help with serotonin deficiency. It includes foods like nuts and seeds, animal protein, and soy, as well as probiotic-rich fermented foods.

You also can ask your healthcare provider about the benefits and risks of boosting your diet with herbs and supplements like ashwagandha.

Herbs and Supplements

More study is needed to confirm the benefits of using herbs and supplements to improve your serotonin levels. However, there is some evidence of benefit with the following:

  • Curcumin, a polyphenol compound in turmeric
  • Folic acid (synthetic vitamin B9) taken as a supplement
  • Naringenin, a flavonoid found in citrus fruits
  • Resveratrol, a polyphenol antioxidant found in grapes, berries, apples, and some nuts
  • Safranal, found in the spice saffron

St. John’s wort also may be used, and for some people it may work as well as SSRI medication. But the two should not be taken together, and St. John's wort can pose a risk (especially with drug interaction) to those treated for other health conditions.

Before trying any supplements, talk to your provider—especially if you're taking prescription medications like antidepressants.

Bright Light

It may help to get plenty of fresh air and sunlight during the day. Some studies also find benefits when using a lightbox or another bright light source.

Keep in mind that digital screen light is different, though. There is some evidence to suggest that high levels of screen time (as with digital addiction) affect serotonin levels and disrupt sleep.

Exercise

There's some evidence to suggest that exercise sessions can raise serotonin levels, although the effects appear temporary and more research is needed to understand the role of exercise.

That said, exercise offers overall benefits (not just in boosting serotonin) that can help with both your physical and mental health, so stay physically active in a way that you enjoy.

Stress Management

Serotonin is considered a stress-related neurotransmitter. Changes in serotonin levels are linked to anxiety and other physical and mental health disorders. Techniques to manage stress include:

  • Breathing techniques
  • Mindfulness and meditation
  • Practicing yoga

Art and music therapy may offer benefits too. One study of music therapy in children and teens diagnosed with attention-deficit hyperactivity disorder (ADHD) found increased serotonin levels with the music therapy sessions.

Summary

Serotonin is an important brain chemical that also works like a hormone. If you don't have enough serotonin, you can have physical and emotional symptoms that can be disruptive to your daily life.

Conditions like chronic fatigue syndrome (CFS) and fibromyalgia might be related to serotonin deficiency. Researchers are studying a host of medical conditions in which serotonin may play a role.

If you think you might have low levels of serotonin, talk to your healthcare provider. There are different ways to raise your levels and keep them up so you can feel and function at your best.

30 Sources
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  1. Endocrine Society. What is serotonin?

  2. Al-Nimer MM, Mohammad TM, Alsakeni R. Serum levels of serotonin as a biomarker of newly diagnosed fibromyalgia in women: Its relation to the platelet indicesJ Res Med Sci. 2018 Aug;23(1):71. doi:10.4103/jrms.JRMS_859_17

  3. Padhy SK, Sahoo S, Mahajan S, Sinha SK. Irritable bowel syndrome: Is it "irritable brain" or "irritable bowel"J Neurosci Rural Pract. 2015;6(4):568-577. doi:10.4103/0976-3147.169802

  4. Wong AC, Devason AS, Umana IC, Cox TO, Dohnalová L, Litichevskiy L, et al. Serotonin reduction in post-acute sequelae of viral infection. Cell. 2023 Oct 9:S0092-8674(23)01034-6. doi:10.1016/j.cell.2023.09.013.

  5. Patrick RP, Ames BN. Vitamin D and the omega-3 fatty acids control serotonin synthesis and action, part 2: relevance for ADHD, bipolar disorder, schizophrenia, and impulsive behavior. FASEB J. 2015;29(6):2207-2222. doi:10.1096/fj.14-268342

  6. da Cunha-Bang S, Knudsen GM. The Modulatory Role of Serotonin on Human Impulsive Aggression. Biol Psychiatry. 2021 Oct 1;90(7):447-457. doi:10.1016/j.biopsych.2021.05.016.

  7. Nautiyal KM, Hen R. Serotonin receptors in depression: from A to BF1000Res. 2017;6:123. doi:10.12688/f1000research.9736.1

  8. Cowen PJ, Browning M. What has serotonin to do with depressionWorld Psychiatry. 2015;14(2):158-160. doi:10.1002/wps.20229

  9. Stanford Medicine. Understanding Obsessive-Compulsive and Related Disorders.

  10. Paredes S, Cantillo S, Candido KD, Knezevic NN. An Association of Serotonin with Pain Disorders and Its Modulation by Estrogens. Int J Mol Sci. 2019 Nov 15;20(22):5729. doi:10.3390/ijms20225729. 

  11. Pourhamzeh M, Moravej FG, Arabi M, Shahriari E, Mehrabi S, Ward R, et al. The Roles of Serotonin in Neuropsychiatric Disorders. Cell Mol Neurobiol. 2022 Aug;42(6):1671-1692. doi:10.1007/s10571-021-01064-9.

  12. Ailani J, Burch RC, Robbins MS; Board of Directors of the American Headache Society. The American Headache Society Consensus Statement: Update on integrating new migraine treatments into clinical practice. Headache. 2021 Jul;61(7):1021-1039. doi:10.1111/head.14153.

  13. Edinoff AN, Raveendran K, Colon MA, Thomas BH, Trettin KA, Hunt GW, et al. Selective Serotonin Reuptake Inhibitors and Associated Bleeding Risks: A Narrative and Clinical Review. Health Psychol Res. 2022 Nov 3;10(4):39580. doi:10.52965/001c.39580. 

  14. Weng R, Shen S, Tian Y, et al. Metabolomics approach reveals integrated metabolic network associated with serotonin deficiency. Sci Rep. 2015;5:11864. doi:10.1038/srep11864

  15. Pho H, Amorim MR, Qiu Q, Shin MK, Kim LJ, Anokye-Danso F, et al. The effect of brain serotonin deficiency on breathing is magnified by age. Physiol Rep. 2022 May;10(10):e15245. doi:10.14814/phy2.15245.

  16. Balakrishna P, George S, Hatoum H, Mukherjee S. Serotonin Pathway in Cancer. Int J Mol Sci. 2021 Jan 28;22(3):1268. doi:10.3390/ijms22031268. 

  17. Jenkins TA, Nguyen JC, Polglaze KE, Bertrand PP. Influence of tryptophan and serotonin on mood and cognition with a possible role of the gut-brain axis. Nutrients. 2016;8(1):56. doi:10.3390/nu8010056

  18. Fields AM, Welle K, Ho ES, Mesaros C, Susiarjo M. Vitamin B6 deficiency disrupts serotonin signaling in pancreatic islets and induces gestational diabetes in mice. Commun Biol. 2021 Mar 26;4(1):421. doi:10.1038/s42003-021-01900-0.

  19. Booij L, Tremblay RE, Szyf M, Benkelfat C. Genetic and early environmental influences on the serotonin system: consequences for brain development and risk for psychopathology. J Psychiatry Neurosci. 2015 Jan;40(1):5-18. doi: 10.1503/jpn.140099.

  20. U.S. Food and Drug Administration. Selective serotonin reuptake inhibitors (SSRIs) information.

  21. UC San Diego Health. Good mood foods.

  22. Lopresti AL, Smith SJ, Malvi H, Kodgule R. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled studyMedicine (Baltimore). 2019;98(37):e17186. doi:10.1097/MD.0000000000017186

  23. Noori T, Sureda A, Sobarzo-Sánchez E, Shirooie S. The Role of Natural Products in Treatment of Depressive Disorder. Curr Neuropharmacol. 2022;20(5):929-949. doi:10.2174/1570159X20666220103140834

  24. Mount Sinai Health Library. St. John’s wort.

  25. Sansone RA, Sansone LA. Sunshine, serotonin, and skin: a partial explanation for seasonal patterns in psychopathology?Innov Clin Neurosci. 2013;10(7-8):20-24.

  26. Dresp-Langley B, Hutt A. Digital Addiction and Sleep. Int J Environ Res Public Health. 2022 Jun 5;19(11):6910. doi:10.3390/ijerph19116910.

  27. Ross RE, VanDerwerker CJ, Saladin ME, Gregory CM. The role of exercise in the treatment of depression: biological underpinnings and clinical outcomes. Mol Psychiatry. 2023 Jan;28(1):298-328. doi:10.1038/s41380-022-01819-w. 

  28. American Psychological Association. Working out boosts brain health.

  29. Qin X, Li J, Wang S, Lv J, Luan F, Liu Y, et al. Serotonin/HTR1E signaling blocks chronic stress-promoted progression of ovarian cancer. Theranostics. 2021 May 8;11(14):6950-6965. doi:10.7150/thno.58956. 

  30. Park JI, Lee IH, Lee SJ, Kwon RW, Choo EA, Nam HW, et al. Effects of music therapy as an alternative treatment on depression in children and adolescents with ADHD by activating serotonin and improving stress coping ability. BMC Complement Med Ther. 2023 Mar 6;23(1):73. doi:10.1186/s12906-022-03832-6. 

By Adrienne Dellwo
Adrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic.