I see many patients who want to have their "hormone levels" checked because they believe a slow metabolism is the reason for their inability to lose weight.

While this may be true, most patients who do get their hormone levels checked for this reason do not have a lack of it.

The hormone in question here is thyroid hormone, made by the thyroid gland, a small, butterfly-shaped gland just above your collarbone in the front of the neck. This hormone is essential to maintain a balance in your metabolism, the sum total of all chemical processes in the body that allow us to function every day. Too much thyroid hormone speeds up metabolism, while too little makes it slow down.

Signs and symptoms of hypothyroidism depend on the severity of the hormone deficiency. Patients feel tired and sluggish, cold all the time, and complain of unexplained weight gain or not being able to lose weight despite decreased caloric intake and exercise. Some may notice thinning of the outer ends of the eyebrows and puffiness around the eyes.

Hypothyroidism can occur if you have an underactive thyroid or if the thyroid gland has been surgically removed due to enlargement or a tumor. It is diagnosed through a blood test called thyroid stimulating hormone. Your doctor may order other lab tests for thyroid function if needed.

The most frequently used treatment for hypothyroidism is replacing the hormone with a substitute, known as levothyroxine. This should be taken at the same time every day, usually first thing in the morning on an empty stomach, taken only with water, and at least 30 minutes before any other food or medication. Also, avoid taking dairy products and any other supplements close to when you take your thyroid hormone.

Do not take the thyroid hormone in excess of what your doctor prescribes. This will not accelerate your weight loss and can cause serious damage to your heart and weaken your bones.

There is a lot of conflicting information out there about the thyroid, and some of it can be very harmful. Your endocrinologist can help interpret your laboratory tests and prescribe the most appropriate treatment for you. Avoid self-medication, taking supplements, or engaging in fad diets — these are not safe.

Once you are treated with thyroid hormone, the rate of your metabolism will return to normal and you should lose some weight. If you are still gaining weight and experiencing additional symptoms, work with your doctor to adjust your medication and follow up regularly, because the dose can change once your weight returns to normal.