Do I need medicine if I have borderline thyroid test results?

American Association of Endocrine Surgeons
American Association of Endocrine Surgeons

When thyroid function tests are borderline, deciding to take thyroid medication can be a difficult decision. Most endocrine specialists recommend waiting at least three months to repeat a borderline abnormal test. However, if a patient is very symptomatic, he or she may be started on medication. The decision to start a medication is one made by both doctor and patient, after a thorough evaluation of the patient’s clinical picture and the risks and benefits of medical treatment.

For more information go the


Dr. Jack Merendino, MD
Dr. Jack Merendino, MD on behalf of The Best Life

First, it is important to understand a little bit about how the thyroid works. The thyroid gland is normally controlled by the pituitary, a hormone-producing gland that sits at the base of the brain. The pituitary gland is sometimes called the “master gland,” because it controls several other hormone-producing glands, including the thyroid, the adrenal glands and the ovaries or testes.

In the case of the thyroid, the pituitary gland makes something called “thyroid stimulating hormone,” or TSH for short. TSH stimulates the thyroid gland to make and release several thyroid hormones that regulate your overall level of metabolism. The two most important thyroid hormones are referred to as T3 or T4, because they contain either 3 or 4 iodine atoms.

If the thyroid gland is making too little T3 or T4, the pituitary gland will sense this and will increase the amount of TSH in an effort to stimulate the thyroid gland into making more. If the thyroid is making too much T3 or T4, the pituitary tries to put the brakes on by reducing the amount of TSH it makes.

Although we can measure T3 and T4 directly in the blood, it turns out that thyroid problems can be diagnosed more reliably by measuring TSH (except when there is a pituitary problem, which is much rarer). If the TSH is high, it means the person has hypothyroidism—an under-active thyroid; if the TSH is low, it means the person has hyperthyroidism, or an over-active thyroid.

The only problem is that some people who have very mild thyroid problems have TSH values that are slightly higher than average, but still in the normal range. In this case, if someone comes in with symptoms that suggest the possibility of hypothyroidism, I may give him or her a trial of thyroid medication to see whether it results in improvement. For example, if a woman comes in complaining of fatigue and has a TSH value of 4.1—in the normal range, but higher than I think is optimal—I may give her a trial of thyroid hormone (levothyroxine; brand names Synthroid or Levoxyl). This can be done safely and later stopped if it is not helpful. However, I would only do this after excluding other common causes of fatigue, such as anemia, sleep disturbances, diabetes, depression and the like.

Continue Learning about Thyroid Disorders

Is Thyroid Eye Disease Impacting Your Sleep?
Is Thyroid Eye Disease Impacting Your Sleep?
Thyroid eye disease (TED) is a condition that affects some people with certain thyroid conditions. The most common thyroid condition associated with T...
Read More
Can a thyroid problem cause night sweats?
Night sweats can be associated with both underactive or overactive thyroid function. Learn more from...
More Answers
What does the tightness in my throat have to do with my thyroid?
Thyroid enlargement may cause a sense of pressure on the neck. Learn more from our experts about tig...
More Answers
Low Thyroid? Here's How to Overcome Fatigue
Low Thyroid? Here's How to Overcome FatigueLow Thyroid? Here's How to Overcome FatigueLow Thyroid? Here's How to Overcome FatigueLow Thyroid? Here's How to Overcome Fatigue
Plus a common hypothyroidism myth, busted. When it’s working properly, your thyroid—a hormone-producing gland at the base of your throat—is an unsung ...
Start Slideshow

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.