11 Thyroid Problem Early Warning Signs You Should Not Ignore

6. Digestive changes: constipation or diarrhea

The thyroid affects digestive rhythm. People with low thyroid function commonly experience slower digestion and constipation. Meals that used to pass easily might now feel heavy or delayed. Conversely, an overactive thyroid speeds up GI transit and can cause more frequent bowel movements or loose stools. Persistent changes in bowel habits that last several weeks should be evaluated, especially if paired with other thyroid signs like weight change or fatigue. Keep a simple food and stool log for a couple of weeks to show patterns. This helps your clinician separate diet- or medication-related causes from possible thyroid involvement. If you have blood in stool, severe abdominal pain, fever, or significant dehydration from diarrhea, seek urgent medical care instead of waiting for routine testing.