T4 Archives - Page 2 of 3 - Dr. Westin Childs | Thyroid & Health Supplements That Work
synthroid overdose: signs you are taking too much thyroid medication

Synthroid Overdose: Signs & Symptoms You’re Taking too Much

Are you concerned that your dose of Synthroid is too high? That may be the case, especially if you are experiencing symptoms such as hair loss, heart palpitations, and heat intolerance.  The good news is that Synthroid overdose can be easily treated by simply reducing your dose.  This article will outline the major side effects associated with taking …

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is synthroid gluten free?

Is Synthroid Gluten-Free?

Are you actively trying to avoid gluten-containing foods? Do you also have hypothyroidism? If so, then this article is perfect for you.  I’m going to jump the gun and tell you that Synthroid is indeed gluten-free, but it may contain other ingredients that can cause issues.  We are going to discuss the gluten content of the thyroid medication …

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Thyroid Deiodinase: How D1, D2 & D3 Enzymes Alter Your Thyroid

Thyroid deiodinase enzymes serve to manage thyroid hormone at every level of metabolism.  Even more important is the fact that these enzymes can become dysregulated by everyday common medical conditions.  Understanding the importance of these enzymes is critical to understanding how to further treatment, especially if you are taking thyroid medication such as levothyroxine or Synthroid.  This post …

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High TSH normal T4: What does it mean?

High TSH & Normal T4: What Does it Mean? + Other Thyroid Lab Patterns

Are you experiencing a high TSH but normal T4? Are you confused about interpreting these values? Is your Doctor telling you that your tests are normal even though you are experiencing abnormal symptoms? This article will help shed light on this thyroid lab pattern and help you understand what it means.  You’ll learn more about the symptoms associated with …

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Is Natural Desiccated Thyroid (NDT) the Best Thyroid Medication?

Is Natural Desiccated Thyroid (NDT) the Best Thyroid Medication?

Natural desiccated thyroid is a thyroid medication that comes from pigs!

This medication contains a more "complete" profile of thyroid hormones when compared to almost all synthetic thyroid medications out there. 

This has lead many people to tout NDT as the "best" thyroid medication. 

In this article, we are going to explore this claim while also discussing the pros and cons of this medication. 

You'll learn who should use this medication, who should avoid it and the pitfalls of using it

Let's dive in: 

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T4 to T3 conversion_ factors that decrease thyroid function

T4 to T3 Conversion: Factors That Decrease Thyroid Function

This is lesson #5 in the thyroid beginner series. 

As you know, this series is designed to help you understand the most basic concepts about thyroid function so you can be a better advocate for your own health

Today is all about T4 to T3 conversion. 

This is the process by which your body creates and activates thyroid hormone. 

It's important because there are steps that you can take to actively enhance this conversion process and help reduce (or improve) your symptoms. 

Let's jump in: 

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T3 basics the test, the medication, the hormone

T3 Thyroid Hormone: What Your Doctor Isn’t Telling You

This is lesson #4 in my thyroid beginner series and today it’s all about the hormone T3.

The last lesson we discussed the value of T4, how it is produced, what it does, and how it influences your body. 

We’re going to do the same thing in this lesson but discuss the other (more active) thyroid hormone: 


Foods to Avoid if you Have Thyroid Problems:

I’ve found that these 10 foods cause the most problems for thyroid patients. Learn which foods you should avoid if you have thyroid disease of any type.


The Complete List of Thyroid Lab tests:

The list includes optimal ranges, normal ranges, and the complete list of tests you need to diagnose and manage thyroid disease correctly!


What is T3?

T3 is the most powerful thyroid hormone that your body produces. 

If you were paying attention yesterday then you know that your thyroid gland, under the influence of TSH, produces T3 thyroid hormone directly. 

In fact, about 20% of the total amount of hormone that your thyroid produces is T3 (1).

This hormone influences almost every cell in your body, through nuclear receptors, and can be tested through routine blood work. 

Your doctor can also prescribe T3 as a medication directly. 

Later in this video and post, we will talk about why many people may actually need T3 medication to feel optimal. 

But let’s focus on T3 as a hormone first. 

T3 as a Hormone

T3 is often referred to as triiodothyronine, especially on lab work or in scientific studies. 

But don’t let this confuse you, because triiodothyronine is another name for T3 and both are referencing the same active thyroid hormone. 

You know that T3 is the most active thyroid hormone in your body, but how does your body get the hormone?

Through 2 main ways:

#1. Your thyroid gland produces it directly (20% or so)

#2. And through the conversion of T4 into T3 (2).

T3 then circulates through your body where it impacts nearly every cell, either on the surface of the cell or directly in the nucleus (3), to cause all of the positive benefits of thyroid hormone. 

T3 is responsible for helping your hair to grow, providing you with energy, helping you lose weight, lifting your mood, increasing your heart rate, managing your cholesterol, and so on. 

All of these benefits come from the effects of T3 on the cell. 

How do you end up with low T3?

Well, if we go back to the two main ways that we know your body produces T3 we can reverse engineer what can cause low T3. 

#1. Your thyroid gland isn’t producing ENOUGH of it.

Conditions such as hypothyroidism, Hashimoto’s thyroiditis, inflammation of the thyroid gland and obesity can all result in reduced production of thyroid hormone directly from your thyroid gland. 

A reduction in either T4 or T3 will lead to low T3 in your body. 


Because of reason #2:

#2. And/or you aren’t able to convert T4 into T3 adequately. 

The thyroid conversion is the process by which your body takes circulating T4 and turns it into T3, through certain enzymes (4), when it needs to. 

If you have a low supply or reservoir of T4 then obviously the amount of T4 that your body can draw upon to create T3 is limited and this may lead to low T3 in your serum (that you can test with lab work). 

If you can identify which issue is causing low T3 in your body then you can help direct your therapy and treatments. 

But just realize that regardless of the reason, if you have low T3 you will likely experience the symptoms of hypothyroidism. 

T3 as a Lab Test

T3 can be easily tested in the blood through two main tests:

#1. Free T3 (amount of unbound active thyroid hormone)

#2. And Total T3 (total amount of T3 in the serum)

Testing for T3 gives you an idea of how much function your thyroid gland has on your body because you are testing for the active thyroid hormone (compare this to T4 which is less biologically active (5)).

T3 is therefore probably the single most important thyroid test that exists (superior to even TSH) (6).

With this in mind, you will want to put a priority on your T3 and ensure that it is in the “optimal” range. 

You can use the example below to illustrate the point: 


In this example, the free T3 is measured at 2.3 with the reference range of 1.7 to 3.7. 

So, from a technical standpoint, the lab is measured in the “normal” range and this is probably what most physicians would tell you. 

But what they fail to realize is that most of your hormones operate on a spectrum ranging from zero function to optimal function and everything in between. 

You can still “function” with a sub-optimal T3 but you may pay the price of fatigue, hair loss, constipation, and weight gain as a result. 

It’s in your best interest, then, to ensure that it is “optimal” for your age. 

You do not want to compare your personal T3 to that of someone in their 80’s or 90’s, instead, you want to compare it to a healthy person that is age-matched to you (currently labs are not set up to give this information) (7).

The “optimal” value will vary from person to person but a safe assumption is that you want your free T3 value in the upper 50% of the reference range that you are given (reference ranges change based on the lab). 

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In a perfect world, you would have tested your free T3 when you were “healthy” and have that as a comparison, but that’s incredibly rare. 

So, without this knowledge, you can assume that a healthy range is probably near the top of the range. 

In our example that would mean that the “optimal range” would be anything greater than 2.7 putting this patient at a slightly sub-optimal level. 

Another important point to mention is that your T3 should always increase if you are taking any type of thyroid medication. 

If your T3 doesn’t increase with medication then you need to take a look at conversion, absorption, or look into using a different type of thyroid medication

T3 as a Medication

T3 can also be used as a medication either by itself or in combination with T4 (and other thyroid medications). 

We’ll get into the various formulations of T3 below.

T3, because it is so powerful, tends to have more side effects when compared to T4. 

This doesn’t necessarily mean that you should avoid T3 medication but it does mean that it’s more difficult to dose correctly and this may be part of the reason that Doctors shy away from using it. 

T3 has a direct influence on your heart cells which can cause your blood pressure and heart rate to increase immediately after taking the medication. 

You may feel this sensation as heart palpitations and/or anxiety. 

These types of symptoms usually go away over time or as you adjust your dose and aren’t necessarily a reason to stop using the medication. 

It’s also important to realize that T3, like thyroid medication, is probably the most effective medication for helping with weight loss (8).

If you are struggling with weight loss, and you have thyroid disease, you need to take a close look at your Free and Total T3 levels (see examples above). 

Liothyronine & Cytomel

Liothyronine and Cytomel would be considered “immediate release” versions of T3 because they are usually rapidly absorbed into the body after ingestion. 

And because T3 has a short half-life, it’s not circulating around in your blood for a significant amount of time (9).

This may be an issue for some people who then opt to take more frequent, but smaller, doses throughout the day. 

This problem is largely solved with SR T3. 


SR T3 is a compounded medication in which the active T3 hormone is bound to a “sticky” material which delays or slows down the absorption of T3 in your intestinal tract. 

This allows for a slow but steady stream of T3 into your body throughout the day. 

SR T3 is often preferred if you experience symptoms such as heart palpitations, anxiety, or headaches when using T3. 

One potential problem with SR T3 is that it may dramatically reduce the absorption of the dose that you take. 

For instance:

If you take 50mcg of SR T3, your body may only absorb some fraction of the total (such as 25mcg or 30mcg of the original 50mcg). 

This typically doesn’t happen with the IR T3s. 


T3 is also found in combination with T4 in medications such as Natural Desiccated Thyroid. 

Natural Desiccated Thyroid (or NDT for short) is dosed differently than other thyroid medications and is referred to as “grains”. 

1 grain of NDT contains around 38mcg of T4 and about 9mcg of T3. 

It’s better to use grains as a unit of measuring the potency of NDT because each formulation has a different set of milligrams which equals 1 grain. 

For instance:

65mg of Nature-Throid = 1 grain while 60mg of Armour Thyroid = 1 grain. 

Don’t let this confuse you though, just realize that NDT contains both T4 and T3. 

Because your thyroid gland (when it is healthy) produces around 80% T4 and around 20% T3 it makes sense to supplement your body with similar ratios. 

This may be why patients who start taking T3 medication often feel much better compared to when they were on T4 medications by themselves. 


T3 fits into the categories of tests, medication, and hormones all in one. 

Understanding what T3 does and how it works is critical to understanding thyroid function in the body because it is considered to do all of the “heavy lifting”. 

Getting your physician to test for T3 and to prescribe T3 medication can be difficult, but certainly not impossible

If you are struggling to get help you can use this as a resource to help you find a knowledgeable physician

But now I want to hear from you:

Have you had your T3 tested? Were your levels optimal?

Are you currently taking T3 medication? How is it working for you?

Are you struggling to find a doctor willing to work with you?

Leave your comments below! 

#1. https://www.ncbi.nlm.nih.gov/pubmed/12915350

#2. ncbi.nlm.nih.gov/pubmed/6479377

#3. ncbi.nlm.nih.gov/pmc/articles/PMC329808/

#4. ncbi.nlm.nih.gov/pmc/articles/PMC3673746/

#5. ncbi.nlm.nih.gov/pmc/articles/PMC4699302/

#6. ncbi.nlm.nih.gov/pubmed/27700539

#7. ncbi.nlm.nih.gov/pubmed/27440910

#8. ncbi.nlm.nih.gov/pmc/articles/PMC3205882/

#9. ncbi.nlm.nih.gov/pmc/articles/PMC5167556/

T3 basics: what your doctor isn't telling you

Causes, Symptoms, and Treatment of Low T4 (Natural + Conventional)

Have you been diagnosed with low T4 through lab testing?   Are you also experiencing symptoms such as fatigue, weight gain, depression or hair loss?   If so, then you may be suffering from low T4 or hypothyroidism.    This post will teach you what you need to know about T4 testing including the symptoms …

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T3 and T4 Thyroid hormone guide

Complete T4 and T3 Guide: What Do They Mean for your Thyroid?

T3 and T4 play a critical role in maintaining thyroid function.    Perhaps more important is that they are often ignored by conventional physicians despite being easily available through routine blood testing.    Learn the importance of T3 and T4 including how to interpret your lab values, how these hormones function in your body, and …

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