Why Free T3 & Total T3 Need to Be Tested on Every Patient with Thyroid Disease

When it comes to testing the thyroid gland, total T3 and Free T3 lab tests are some of the most important markers in evaluating thyroid function.

These hormones are the active forms of thyroid hormone and by testing them, they provide information not only on how your body is using thyroid hormones but also where potential problems in your thyroid disease are rooted. T3 and Free T3 are not part of the standard thyroid screening panel. These are tests that are used with other thyroid lab tests.

What Does Free T3 Test For? What Does It Mean

If you have experienced thyroid symptoms, or you are taking thyroid medication, then you have already had your TSH or Thyroid Stimulating Hormone tested.

TSH is made in the brain and it tells the Thyroid gland to make the thyroid hormones T4 and T3. Together, these hormones regulate your body’s temperature, metabolism, heart rate and so much more. But testing your total T3 and free T3 is a different story and a doctor should never rely only on a TSH to predict Free T3 and Free T4 levels.

Studies show us that the TSH test alone fails to predict free T3 and free T4 levels in patients who are taking thyroid medication.

If that sounds confusing, let me break this down, let’s say you are taking thyroid medication perhaps you are on Levothyroxine or Synthroid) and you have a completely normal TSH, does this mean your thyroid levels are normal? Absolutely NOT! This in fact is one of the many reasons people still feel terrible despite taking medication and despite having “normal” TSH levels.

Moral of this story… Don’t rely on TSH as the determining factor of your hormone levels. You must test the actual thyroid hormones levels.

Testing Free T3 tells us how active your thyroid hormone is at the cellular level and this is what we really want to know.

T3 is the hormone that is responsible for attaching onto the surface and the nucleus of your cells and activating the genes within the cell.

Ok But What happens if I don’t have enough Free T3?

You suffer with the symptoms of hypothyroidism. This is term that describes a condition in which the thyroid gland does not produce sufficient amounts of thyroid hormones. People who have Low T3 suffer with Fatigue, weight gain, depression, digestive problems, chronic pain, Inflammation, Brain Fog, low heart rate, acid reflux and many other low thyroid symptoms. Remember its T3 and Free T3 that make the magic happen in your body.

There are many reasons why people have low T3 or low Free T3 and a good doctor is a good investigator. Don’t fall into the common misbelief that T3 replacement (Armour or Cytomel) is the fix to your low thyroid symptoms.

Dumping T3 into the body is NOT the answer. The solution to correcting low T3 is finding out what the cause is. This varies from person to person. Your cure to your thyroid problems lies in the cause. Many doctors are quick to prescribe T3, but this is no different than the doctor who prescribes T4. It just doesn’t address the cause.

• Download my Free Thyroid Guide to Learn more
• Use My T3/Reverse T3 calculator to assess your Thyroid function. TSH testing can be misleading if you have a thyroid problem- this is why the T3/Reverse T3 ratio is so important.
• Take my Thyroid Quiz and get recommendation on what action steps you should take today.

Is Having A High Free T3 Dangerous? (Symptoms of High Free T3)

Just like having a low free T3 is potentially dangerous having high free T3 is also dangerous. High T3 levels can indicate several conditions, including hyperthyroidism, Graves disease (autoimmune)thyrotoxicosis (excess circulating hormones) and thyroid overmedication.

Symptoms of High T3, Graves Disease and Thyrotoxicosis

• sweating
• tremors
• sensitivity to heat or cold
• tiredness
• irritability
• mood swings
• unexplained weight loss
• difficulty sleeping
• bulging or irritated eyes
• hair loss
• irregular or slower heartbeat
• shortness of breath
• high blood sugar
• increased frequency of urination

What Are Good Free T3, Total T3 levels?

This is great question but just as all things with the thyroid, we don’t have a straightforward answer. Here again, we need to demystify “good levels” versus optimal Thyroid levels. There are few things you need to know.

First, different lab companies create their own reference ranges based on averages and based on location.

So, what this means is that a lab testing your thyroid levels in New York is comparing your thyroid levels to other people in NY and a Lab out on the California is comparing your thyroid levels to other people who live in California. If that’s not a problem all by itself, thing get a little more confusing when we talk about thyroid lab ranges.

Also worth mentioning, is that these Thyroid lab ranges are based on AVERAGES. The average may be people of different ages, different sex (male versus female) and if they are healthy or sick at the time of testing. That means the reference range is compiled of a bunch of both healthy and unhealthy people which can skew the range. That means the “normal” reference range is compiled of a bunch of both healthy and unhealthy people which can skew the “normal” range. There’s more to this…….research shows us that timing of the day and if you fasted or not can influence your thyroid levels. Can you see why lab ranges are so confusing and why many people wind up getting overmedicated.

This is why at my clinic, we rely on Functional lab ranges. Functional lab ranges compare your test results to people who have healthy thyroid levels not sick people. I encourage to learn more about Functional lab ranges as well as understanding why a complete thyroid panel including T3 and Free T3 is so important.

Closing Thoughts About Today’s Article.

1. Testing free T3 and Total T3 levels are important. You Cant rely on TSH levels alone to determine Thyroid hormone levels.
2. Testing your Total T3 and free T3 is part of a comprehensive Thyroid Panel.
3. Total T3 and Free T3 levels tell you how much of the active hormone you have and can help with proper thyroid management and treatment.
4. Total T3 and Free should be used in conjunction with other lab tests such as TSH, Total T4, Reverse T3, TBG and Thyroid antibodies. This gives the most complete picture of thyroid function.
5. Download my Thyroid E-book and subscribed to my Thyroid Newsletter. It will help you appreciate why the Thyroid is complex and perhaps explain why you continue to struggle with many thyroid symptoms.
6. Make sure you work with a doctor who uses Functional Thyroid lab ranges and most importantly….Test don’t Guess