5-HTP for Fibromyalgia & Chronic Fatigue Syndrome

What We Know About It

A nutritional supplement called 5-HTP is among the more popular supplements used for treating fibromyalgia (FMS) and chronic fatigue syndrome (CFS or ME/CFS).

Woman sits on her bed looking at the floor
Arief Juwono / Getty Images

5-HTP stands for 5-Hydroxytryptophan, and it's an amino acid that your body makes naturally. You might recognize "tryptophan" as the stuff in turkey that's rumored to make you tired--5-HTP is a form of that.

5-HTP has several roles in your body, but the one that drew the interest of FMS and ME/CFS healthcare providers and researchers is that it's one of the ingredients your body uses to create serotonin, which is an important neurotransmitter (chemical messenger in the brain) as well as a hormone.

Serotonin Dysregulation

Research strongly suggests that these conditions both involve serotonin dysregulation, which means that we either don't have enough of it or our bodies don't use it properly for some reason.

Symptoms of serotonin dysregulation can include:

  • Fatigue, in spite of adequate rest
  • Disturbed sleep
  • Changes in appetite
  • Hot flushes and temperature changes
  • Headaches
  • Changes in libido
  • Mood disturbances
  • Depression
  • Irritability

When serotonin levels are extremely low, you may experience additional symptoms on top of those listed above. These may include:

  • Muscle cramps
  • Bowel & bladder problems
  • Rapid, uncontrolled thought processes
  • Emotional numbness
  • Emotional or behavioral outbursts
  • Escape fantasies
  • Memory torture (dwelling on or reliving your most traumatic experiences)
  • Thoughts of harming yourself or others

Serotonin is involved in a lot of important functions in your brain, so a lot can go wrong when it's dysregulated. Other conditions that are believed to be associated with serotonin dysregulation include:

  • Depression (which overlaps with FMS and ME/CFS)
  • Insomnia (which overlaps with FMS and ME/CFS)
  • Restless leg syndrome (which overlaps with FMS and ME/CFS)
  • Irritable bowel syndrome (which overlaps with FMS and ME/CFS)
  • Obsessive-compulsive disorder
  • Anorexia and bulimia
  • Social anxiety (which overlaps with FMS and ME/CFS)
  • Phobias 
  • Attention Deficit Disorder (ADD/ADHD)
  • Post-traumatic stress disorder (which overlaps with FMS and ME/CFS)
  • Alcoholism

Many of the treatments for FMS, ME/CFS, and the above disorders target serotonin levels or function. 5-HTP is one of those.

Tryptophan in ME/CFS

Research also links abnormalities in tryptophan to ME/CFS. A study by Anderson, Berk, and Maes suggests that this finding may help link similar conditions that involve fatigue, malaise, hyperalgesia, and several other symptoms.

How Much 5-HTP Should You Take?

There's a lot of wiggle room in the standard dosages for 5-HTP. You can find recommendations from 50 mg per day up to 500 mg a day.

People with FMS and ME/CFS are often sensitive to drugs and supplements and may experience unwanted side effects more often than most people. Because of this, the best course of action with most treatments is to start with a very low dosage and increase it slowly.

If you're taking a drug that alters serotonin levels, be sure to talk to your healthcare provider and/or pharmacist before adding 5-HTP to your treatment regimen. Too much serotonin can lead to a dangerous, and possibly even fatal, condition called serotonin syndrome. These drugs can include any of the FDA-approved FMS drugs—Lyrica (pregabalin), Cymbalta (duloxetine), or Savella (milnacipran)—and any antidepressant.

Verywell.com's Expert on Alternative Medicine, Cathy Wong, has compiled a helpful list of other possible 5-HTP drug interactions.

5-HTP in Your Diet

You might be tempted to try increasing 5-HTP levels through food containing tryptophan. However, that's not likely to help alleviate your FMS and ME/CFS symptoms.

That's because the tryptophan contained in foods, such as turkey, isn't plentiful enough to significantly increase your 5-HTP levels. It may also be unable to reach your brain due to the blood-brain barrier. Meanwhile, 5-HTP supplements contain higher levels, are easily absorbed by your body, and do pass through the blood-brain barrier, so they're believed to be much more effective than dietary tryptophan.

Side Effects of 5-HTP

People tend to think of natural treatments as "safe," but they can still cause negative side effects.

Possible side effects of 5-HTP include:

  • Nausea
  • Dizziness
  • Diarrhea

Some people are allergic to 5-HTP supplements, but it's quite rare.

So far, we don't have good safety data on 5-HTP usage during pregnancy or breastfeeding, or in people with liver or kidney disease.

Research suggests that children with Down's syndrome should not take 5-HTP.

A Word From Verywell

Especially because of the risks of combining multiple serotonin-enhancing treatments, be sure to talk to your healthcare provider about 5-HTP before you begin taking it. Your pharmacist is a good resource for looking into possible drug interactions, as well.

5-HTP isn't recommended as the only treatment for FMS and ME/CFS, but as part of a larger treatment regimen that may include drugs, other supplements, and many other approaches.


Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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