Many people are, and don't even know it, although the lab tests are pretty simple. What's more, there are MANY symptoms of low thyroid...
- Abnormal blood pressure
- Abnormal cholesterol levels
- Abnormal menstrual cycles
- Abnormal resting pulse rate
- Brittle fingernails and hair
- Decreased libido
- Depression and/or anxiety/panic
- Fertility problems
- Hair loss
- Hoarse voice
- Impaired immune function
- Increased sensitivity to cold
- Joint pain, stiffness, or swelling
- Memory loss
- Muscle aches, tenderness, and stiffness
- Pale, dry skin
- Puffy face
- Unexplained weight gain
Another factor is that people can test within normal levels, but still may need more thyroid, as the level is apparently not normal for them!
Check out my HND piece on the subject.