A butterfly-shaped gland located in the neck, is the master gland of metabolism. When your thyroid doesn't function, it can affect every aspect of your health, and in particular, weight, depression and energy levels.

Since undiagnosed thyroid problems can dramatically increase your risk of obesity, heart disease, depression, anxiety, hair loss, sexual dysfunction, infertility and a host of other symptoms and health problems, it's important that you don't go undiagnosed.

You don't need to have all of these symptoms in order to have a thyroid problem, but here are some of the most common signs that you may have a thyroid condition:

10. Muscle and Joint Pains, Carpal Tunnel/Tendonitis Problems.

Aches and pains in your muscles and joints, weakness in the arms and a tendency to develop carpal tunnel in the arms/hands and tarsal tunnel in the legs, can all be symptoms of undiagnosed thyroid problems.

9. Neck Discomfort/Enlargement.

A feeling of swelling in the neck, discomfort with turtlenecks or neckties, a hoarse voice or a visibly enlarged thyroid can all be symptoms of thyroid disease.

To help find out if your thyroid may be enlarged, try a simple "Thyroid Neck Check" test at home.

8. Hair/Skin Changes.

Hair and skin are particularly vulnerable to thyroid conditions, and in particular, hair loss is frequently associated with thyroid problems. With hypothyroidism, hair frequently becomes brittle, coarse and dry, while breaking off and falling out easily. Skin can become coarse, thick, dry,and scaly. In hypothyroidism, there is often an unusual loss of hair in the outer edge of the eyebrow. With hyperthyroidism, severe hair loss can also occur, and skin can become fragile and thin.

7. Bowel Problems.

Severe or long-term constipation is frequently associated with hypothyroidism, while diarrhea or irritable bowel syndrome (IBS) is associated with hyperthyroidism.

6. Menstrual Irregularities and Fertility Problems.

Heavier, more frequent and more painful periods are frequently associated with hypothyroidism, and shorter, lighter or infrequent menstruation can be associated with hyperthyroidism. Infertility can also be associated with undiagnosed thyroid conditions.

5. Family History.

If you have a family history of thyroid problems, you are at a higher risk of having a thyroid condition yourself. You may not always be aware of thyroid problems in your family, though, because among older people, it is often referred to as "gland trouble" or "goiter." So pay attention to any discussions of glandular conditions or goiter or weight gain due to "a glandular problem," as these may be indirect ways of referring to thyroid conditions.

4. Cholesterol Issues

High cholesterol, especially when it is not responsive to diet, exercise or cholesterol-lowering medication, can be a sign of undiagnosed hypothyroidism. Unusually low cholesterol levels may be a sign of hyperthyroidism.

3. Depression and Anxiety.

Depression or anxiety — including sudden onset of panic disorder — can be symptoms of thyroid disease. Hypothyroidism is most typically associated with depression, while hyperthyroidism is more commonly associated with anxiety or panic attacks. Depression that does not respond to antidepressants may also be a sign of an undiagnosed thyroid disorder.

2. Weight Changes.

You may be on a low-fat, low-calorie diet with a rigorous exercise program, but are failing to lose or gain any weight. Or you may have joined a diet program or support group, such as Weight Watchers, and you are the only one who isn't losing any weight. Difficulty losing weight can be a sign of hypothyroidism. You may be losing weight while eating the same amount of food as usual — or even losing while eating more than normal. Unexplained weight changes and issues can be signs of both hypothyroidism or hyperthyroidism

1. Fatigue.

Feeling exhausted when you wake up, feeling as if 8 or 10 hours of sleep a night is insufficient or being unable to function all day without a nap can all be signs of thyroid problems. (With hyperthyroidism, you may also have nighttime insomnia that leaves you exhausted during the day.