Physical and Emotional Symptoms of Low Serotonin

Sad woman suffering from insomnia while sitting on her bed

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Many symptoms of fibromyalgia (FMS) and chronic fatigue syndrome (CFS or ME/CFS) are believed to be tied to low levels of the neurotransmitter serotonin. These can include pain, fatigue and low energy, depression and negative thoughts, irritability, anxiety, low energy, abdominal problems, binge eating, and a reduced interest in sex. The assortment of symptoms can be confusing and bewildering, not to mention no fun to live with.

But as varied as the problems are, they're not the only related to serotonin, which is both a neurotransmitter (in your brain) and a hormone (in the rest of your body.)

What Serotonin Does

Serotonin is a regulator of all kinds of processes, so it's no wonder that when it's out of whack, nothing is regular. That's why you feel like your body is falling apart and your symptoms don't make any sense.

Serotonin's dual nature, as a neurotransmitter and hormone, means it's found all over your body. In fact, there's more serotonin in your gut than in your brain. That may explain why illnesses such as irritable bowel syndrome (IBS) are extremely common in FMS and ME/CFS: IBS involves low serotonin as well.

By recognizing symptoms of serotonin dysregulation, you may be able to not only understand your crazy symptoms but actually improve your chances of proper diagnosis and treatment.

Physical Serotonin-Related Symptoms

Doctors don't test your neurotransmitter levels. Instead, they rely on symptoms for making diagnoses. For that reason, it's important for you to know what symptoms may be linked to serotonin. Otherwise, you may choose only one or two to focus on with your doctor, and that can get in the way of figuring out what's wrong.

What we call "low" serotonin may come from a couple of different causes: either your body doesn't make enough, or it doesn't use it efficiently. Either way, the result is the same.

Some of the major physical symptoms of low serotonin are:

  • Chronic fatigue in spite of adequate rest
  • Disturbed sleep
  • Either loss of appetite or carb cravings, possibly due to the body's attempt to make more serotonin
  • Hot flushes and temperature changes that aren't 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 here is to recognize whether you have clusters of symptoms that tend to occur together. Serotonin levels can fluctuate over time, leading to symptom flares and remissions (times when symptoms are gone or at low levels.)

Emotional Serotonin-Related Symptoms

The presence of emotional symptoms in no way implies that FMS or ME/CFS are psychological illnesses. In fact, we know that they both include numerous physiological abnormalities. FMS is generally considered a neurological condition and both of these illnesses are sometimes called neuroimmune diseases or neuroendocrine-immune diseases.

It's true that serotonin (and many other neurotransmitters) are also involved in mental illness, such as major depressive disorder. Even in these cases, they represent a physiological problem. Neurotransmitters are also involved in numerous non-psychological conditions, including Parkinson's disease.

Emotional symptoms include:

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

If your sadness and other emotional symptoms are especially pronounced, you should talk to your doctor about depression. It's common in FMS and ME/CFS, as it is in all chronic, debilitating illness.

Again, look for symptom clusters that could indicate low serotonin.

A Word From Verywell

If you think your serotonin is low, talk to your doctor. You may need to consider treatments that raise your available amount of serotonin.

Probably the most common treatment is medication: antidepressants such as selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), or tricyclics. Some supplements and your diet can influence serotonin as well.

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