Changes in thyroid hormones can cause a mix of body and mood symptoms, but the only way to know for sure is with blood tests ordered by a clinician. If anything on this list sounds familiar or is worrying, it is worth talking with a doctor or clinic.
Common low thyroid signs
With an underactive thyroid (hypothyroidism), symptoms usually build slowly and can be easy to miss. Typical patterns include:
- Feeling very tired, low energy, or “slowed down,” often with low mood or brain fog.
- Feeling cold when others are comfortable, gaining weight without trying, and having constipation.
- Dry or brittle hair and skin, hair thinning, puffy face, hoarse or deeper voice, and heavier or more irregular menstrual periods if you have them.
Common overactive thyroid signs
With an overactive thyroid (hyperthyroidism), the body tends to speed up. Typical patterns include:
- Unexplained weight loss despite normal or increased appetite, feeling hot or sweaty, and a fast or pounding heartbeat.
- Feeling jittery, anxious, or irritable, with shaky hands and trouble sleeping.
- Frequent bowel movements or diarrhea, muscle weakness (especially in arms or thighs), and sometimes a swelling in the neck (goiter) or eye redness/bulging with Graves’ disease.
When to get checked
Because these symptoms overlap with many other conditions, testing is important rather than guessing. A clinician will usually:
- Ask about symptoms and examine your neck, heart rate, and reflexes, and may feel for an enlarged thyroid.
- Order blood tests that measure TSH and thyroid hormones (T4, sometimes T3), and sometimes thyroid antibodies or imaging if an autoimmune thyroid disease is suspected.
What you can do now
If you are worried your thyroid is “off,” focus on specific changes you have noticed and how long they have been happening, and bring that description to a clinician. If you have red-flag symptoms such as very fast heartbeat, chest pain, severe shortness of breath, sudden major swelling in the neck, or confusion, seek urgent or emergency care.