Reviewed by:  Dr. Robert Cooper, M.D., FACE

Hypothyroidism occurs when the thyroid does not produce enough of the thyroxine (T4) and triiodothyronine (T3), thyroid hormones that help control the body’s metabolism. Lower levels of these hormones can slow the metabolism, the process that the body uses to digest food and nutrients and create and use energy.

Those at greater risk for hypothyroidism include women, especially those over age 50. The signs and symptoms of hypothyroidism vary greatly, depending on just how much the metabolism has slowed, and symptoms usually appear slowly, over a number of years. The most common symptoms:

• Unexplained fatigue that is not relieved by rest
• 
  
• Cold sensitivity that changes or differs from others in the same environment. It may also include cold skin
• 
  
• Constipation not associated with a change in diet
• 
  
• Brittle, thinning hair and fingernails
• 
  
• Depression
• 
  
• Skin that becomes pale, dry or scaly, or thickens
• 
  
• Weight gain with no change in diet or exercise routines
• 
  
• Muscle aches and weakness
• 
  
• Joint pain, stiffness or swelling
• 
  
• Impaired concentration, forgetfulness or confusion

There are many other symptoms caused by hypothyroidism, all of which may be associated with multiple conditions. Because women are at greater risk for the hypothyroidism, a blood test is usually to first tool a physician will use to determine the cause of any chronic symptoms.

What's Next: 10 Signs of an Overactive Thyroid

• Avoid the Risks of Thyroid Disease
• Get Your Thyroid Tested
• Check Your Neck
• Lifestyle Tips for a Healthy Thyroid
• Ask Your Doctor About Hypothyroidism
• Ask Your Doctor About Hyperthyroidism

Review Date: November 19, 2008