Constipation: The Thyroid Symptom No One Wants to Talk About

Overview of Constipation in Hypothyroidism

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Constipation is a problem that can be particularly troublesome for people with hypothyroidism (an underactive thyroid).

Hypothyroidism slows down many of the body's systems, including digestion and elimination. And unfortunately, some people can end up being chronically constipated as a result.

Defining Constipation

Constipation is traditionally defined as having three bowel movements or less in a week. Other than the frequency of bowel movement, other criteria used to define constipation include symptoms like the need to strain during bowel movements, lumpy or hard stools, and a sensation that bowel movements are incomplete or blocked in some way. Also, some people with constipation report having to use manual maneuvers to facilitate bowel movement (for example, digital evacuation). 


As food moves through the colon, also known as the large intestine, water from food is absorbed. After the water is absorbed, waste product (stool) is formed. Muscles in the colon contract to move the stool through the intestine toward the rectum. Water continues to be absorbed so that the stool becomes more solid before elimination.

Constipation occurs because too much water is absorbed from the food, or the colon isn't contracting frequently or strongly enough. The stool moves too slowly as a result.

Sluggish, slower, or weaker colon contractions (called reduced gut motility) is characteristic of hypothyroidism.


First, you want to be sure that your thyroid treatment is optimized, as insufficient treatment may contribute to constipation problems.

Other strategies your doctor may recommend, include:

Increase Your Fiber Intake

Dietary changes, including getting 25 to 35 grams of fiber a day, is a good start for managing your constipation. High-fiber foods include many fruits and vegetables, whole grain breads, and cereals, and beans. Some of the highest fiber foods include fruits like berries, greens, and whole grains. 

As an aside, some high-fiber foods are considered "goitrogenic," which means that they may aggravate hypothyroidism. Usually, though, this risk is highest when these foods are eaten raw and in excessive quantities. 

If you are unsure how to incorporate fiber into your diet, consider seeing a nutritionist or bringing a food diary to your doctor appointment. 

You may also consider a fiber supplement if you find it challenging to get the right amount of daily fiber through your diet.

Be wary though, as fiber in your diet and fiber supplements may affect the absorption of your thyroid hormone. This is why it's important to take your thyroid medication first thing in the morning and then wait two to three hours before eating or taking any medications or supplements. 

Lifestyle Changes

Make sure that you are getting enough liquid. This means at least 64 ounces a day (not including caffeinated beverages). Daily exercise is essential. Even a short walk is helpful to get things moving.

Make sure that you have enough time, and privacy, for a comfortable bowel movement. And don't ignore, put off or delay the urge for a bowel movement.


If you have tried diet and lifestyle changes and are still suffering from chronic constipation, you'll want to talk to your doctor about laxatives. Because chronic constipation should be evaluated by your physician, and most laxatives can be habit-forming, it's best not to self-treat with laxatives. Instead, talk to your practitioner for guidance.

Complementary Approaches

A number of natural treatments may also helpful like probiotic therapy, yoga, or biofeedback. 


Occasionally, chronic constipation can lead to additional complications. The most common are hemorrhoids, rectal prolapse, or fecal impaction. Ideally, your doctor's treatment should help avoid these sorts of serious complications.

If diet, exercise, lifestyle changes, and over-the-counter or prescription medications (and proper thyroid treatment for thyroid patients ) are not resolving chronic constipation, then consultation with a gastroenterologist for more extensive testing will likely be recommended.

Other Causes

In addition to the general intestinal slowdown and fluid accumulation that are characteristic of hypothyroidism, there are other causes of constipation:

  • Eating too much meat, cheese, and low-fiber foods, and not enough fiber (like whole grains)
  • Not drinking enough liquids/dehydration
  • Physical inactivity (especially in the elderly)
  • Medications, including pain medications (especially narcotics such as codeine and oxycodone prescribed after surgery), antacids that contain aluminum and or calcium, blood pressure medications, antidepressants, anticonvulsants, diuretics, drugs for Parkinson's disease, and antispasmodics.
  • Supplements, especially those containing iron
  • Overuse of laxatives 
  • Ignoring the urge to have a bowel movement
  • Specific diseases or conditions, such as irritable bowel syndrome, neurological disorders (stroke, Parkinson's, MS), metabolic problems such as diabetes, and autoimmune diseases such as amyloidosis, lupus, and scleroderma
  • Problems with the colon and rectum, including intestinal obstructions, tumors, scar tissue, and adhesions
  • Other issues, including pregnancy and traveling

A Word From Verywell

If you are suffering from chronic constipation see your doctor for a comprehensive evaluation, which will include a thyroid evaluation (if not already done). 

Keep in mind that you should see your doctor right away if your constipation has come on very rapidly with no reason. Also, see your physician if constipation is accompanied by symptoms such as bleeding from the rectum, rectal bleeding, abdominal pain, cramps, nausea, vomiting, or noticeable weight loss.

In general, however, most doctors will start with a medical history and physical exam. The doctor will want to know about the frequency of your bowel movements, the characteristics of your stool, your eating and drinking habits, medications you take, and your level of physical activity.

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  • Jamshed N, Lee Zon-En, Olden KW. Diagnostic approach to chronic constipation in adults. Am Fam Physician. 2011 Aug 1;84(3):299-306.
  • National Institute of Diabetes and Digestive and Kidney Diseases. (n.d.). Constipation