Clicky

DrBayer.com

DrBayer.com

Leaky Gut Symptoms: What They Mean and What Else Causes Them

by

The short answer: “leaky gut” is not a recognized medical diagnosis, and there is no standard test that measures it directly in patients. Bloating, fatigue, diarrhea or constipation can come from several well-defined conditions, including celiac disease, Crohn's disease, irritable bowel syndrome, food intolerance, and thyroid disease. A doctor can test for those. If your symptoms last or keep coming back, see a clinician before you change your diet.

By DrBayer.com Editorial Team. This is general education, not medical advice, and it was not written or reviewed by a named clinician. The linked sources were opened and read on October 3, 2026.

What “Leaky Gut” Means, and What Is Not Proven

Cleveland Clinic describes leaky gut syndrome as a hypothetical condition in which the intestines become permeable to toxins that leak into the bloodstream and trigger systemic disease. It states that it is not currently a recognized medical diagnosis and that there is no standard test to measure intestinal permeability directly in patients (Cleveland Clinic, last updated April 2022).

Harvard Health Publishing, in an article by Toni Golen, MD, published July 1, 2024, also says leaky gut isn't a clinical diagnosis. It advises that anyone who has been dealing with chronic intestinal symptoms should see a doctor (Harvard Health Publishing).

The practical point: an online symptom list that ends in “you may have leaky gut” does not tell you which condition is behind your symptoms. Several of the conditions below can be tested for.

Symptom-to-Possible-Cause Guide

This guide matches commonly reported symptoms with conditions that can overlap with them. It is a starting point for your appointment, not a way to diagnose yourself. A symptom listed under a condition does not mean you have that condition, and the lists are not complete.

Bloating and gas

  • Celiac disease: NIDDK lists bloating, gas and chronic diarrhea among symptoms in adults (NIDDK, celiac disease, last reviewed October 2020).
  • Irritable bowel syndrome (IBS): NIDDK lists bloating among IBS symptoms, alongside abdominal pain and changes in bowel movements (NIDDK, IBS, last reviewed November 2017).
  • Lactose intolerance (one type of food intolerance): NIDDK lists bloating, diarrhea, gas, nausea and abdominal pain, and explains that lactose intolerance and milk allergy are different conditions with different causes (NIDDK, lactose intolerance, last reviewed February 2018).

Fatigue and low energy

  • Celiac disease: NIDDK lists fatigue, or feeling tired, and joint or bone pain among its symptoms.
  • Crohn's disease: NIDDK lists feeling tired, anemia, fever and joint pain or soreness among additional symptoms (NIDDK, Crohn's disease, last reviewed July 2024).
  • Hypothyroidism (underactive thyroid): NIDDK lists fatigue, weight gain, trouble tolerating cold, joint and muscle pain, and dry skin or dry, thinning hair, and notes that symptoms can develop gradually and may not be noticeable for months or years (NIDDK, hypothyroidism, last reviewed March 2021).

Diarrhea, cramping or belly pain

  • Crohn's disease: NIDDK names diarrhea, cramping and pain in your belly, and weight loss as the most common symptoms.
  • IBS: pain in your abdomen, often related to bowel movements, with diarrhea, constipation, or both.
  • Celiac disease and lactose intolerance: both can include diarrhea, as listed above.

Constipation

  • IBS: bowel changes can be diarrhea, constipation, or both.
  • Other causes: Harvard Health's leaky gut article also lists constipation among the symptoms it discusses, so the symptom alone does not point to one cause. NIDDK's constipation page lists warning signs that call for prompt attention (see the checklist below).

Why symptoms alone cannot sort this out

These lists overlap. NIDDK explains that doctors diagnose IBS from symptom patterns, and that tests such as blood tests, stool tests, upper endoscopy with biopsy (for celiac disease) and colonoscopy (for colon cancer or inflammatory bowel disease) are used to check for other conditions (NIDDK, IBS diagnosis, last reviewed November 2017). For hypothyroidism, NIDDK says doctors may use several thyroid blood tests and imaging tests to confirm the diagnosis.

One caution on celiac disease: NIDDK states that doctors don't recommend starting a gluten-free diet before diagnostic testing, because a gluten-free diet can affect test results (NIDDK, celiac disease diagnosis, last reviewed October 2020). Ask your doctor before you cut gluten out.

Red-Flag Symptoms to Raise With a Doctor Promptly

NIDDK's IBS diagnosis page lists these as warning signs that suggest a condition other than IBS and call for further investigation:

  • Bleeding from your rectum, or bloody stools, or stools that are black and tarry
  • Weight loss
  • Anemia
  • A family history of celiac disease, colon cancer, or inflammatory bowel disease

NIDDK's constipation page says to seek immediate medical attention if you are constipated and also have any of these:

  • Bleeding from your rectum or blood in your stool
  • Constant pain in your abdomen
  • Inability to pass gas
  • Vomiting
  • Fever
  • Lower back pain
  • Losing weight without trying

These lists do not cover every warning sign. If you think you are having an emergency, call your local emergency number.

Printable Symptom Log

A log makes an appointment more productive because patterns are hard to remember. Copy this into a notes app or print it, and fill it in for a few weeks. Record what happened rather than guessing at causes.

  1. Date and time: ______
  2. Symptom and severity (0 to 10): bloating, gas, belly pain, diarrhea, constipation, nausea, fatigue, other ______
  3. What you ate and drank in the previous hours: ______
  4. Bowel movements: number, and whether stools were loose, hard, bloody, or black ______
  5. Medicines and supplements taken: ______
  6. Sleep and energy that day (0 to 10): ______
  7. Anything else: fever, weight change, joint pain, skin or hair changes ______
  8. Questions for my doctor: ______

Bring the log, a list of everything you take, and your family history of digestive or thyroid disease.

What to Do Next

  • Book a visit if symptoms last or keep coming back. Harvard Health says anyone dealing with chronic intestinal symptoms should see a doctor. Cleveland Clinic says a qualified gastroenterologist can help sort through the possible causes of your specific symptoms.
  • Ask which tests make sense for you. That decision belongs to you and your clinician.
  • Do not start a gluten-free diet before celiac testing unless your doctor tells you to.
  • Tell your doctor about supplements and medicines you take. Harvard Health notes that doctors typically review dietary intake, supplements and medications when evaluating gut symptoms.

Related Reading on This Site

If you have already been evaluated and want background on how dietary and supplement-based approaches to intestinal permeability are discussed, see our separate article, Leaky Gut Healing Protocol: L-Glutamine, Zinc Carnosine, Bone Broth, and Elimination Diet Approach. Read it with this guide's limits in mind: leaky gut is not a recognized diagnosis, and persistent symptoms deserve a medical evaluation first.

Limits of This Guide

This guide covers a short list of overlapping conditions and is not complete. It cannot tell you which, if any, applies to you. The sources carry different review dates, ranging from 2017 to 2024, and guidance can change, so confirm current advice with your clinician.

Sources