Reverse T3 could be the missing link to finding out why you still have hypothyroid symptoms despite taking thyroid medication.
Or why you feel terrible with "normal" lab tests...
The crazy part is that most Doctors don't even order Reverse T3 and even if they do most aren't sure what to do with the results.
And high levels of Reverse T3 could be acting to slow down your metabolism, reduce thyroid function at the cellular level and result in full-blown symptoms of hypothyroidism.
That's why it's so important for you to understand the basics of Reverse T3 and thyroid function so you can be informed when you see your Doctor.
And don't worry:
I am going to make this easy on you by giving you all of the information you need to know about Reverse T3 including:
- How to tell if you have too much Reverse T3 in your body
- What blood tests you need to have your Doctor order and how to calculate your Free T3:Reverse T3 ratio
- What causes high levels of Reverse T3
- How to "flush" out high levels of reverse T3 and how I treat patients with Thyroid resistance and high levels of Reverse T3 in my office
What is Reverse T3 Anyway?
Are you new to this whole thyroid thing?
No worries, I'm going to make this easy on you.
There's a lot of information out there (much of it conflicting), and it's easy to get lost in the sea.
What it boils down to is this:
Reverse T3 is a hormone metabolite that is created from the T4 thyroid hormone (1). And it looks something like this:
Your body basically has the option of converting T4 into the ACTIVE thyroid hormone T3 or the INACTIVE thyroid metabolite Reverse T3.
Much like the image above, it's sort of like a fork in the road. Your body is constantly deciding which direction it is going, left or right.
If most of the T4 in your body goes down the ACTIVE T3 pathway, then your tissues get the thyroid hormone they need and everything is good.
If too much goes down the INACTIVE Reverse T3 pathway, then the active thyroid hormone is BLOCKED and you may become symptomatic.
Sounds pretty simple right?
T3 hormone = Good
Reverse T3 metabolite (in high amounts) = Bad
Now that we know what we want the body to do, let's focus on doing the things that help your body convert T4 into the active T3 hormone and NOT the inactive Reverse T3 metabolite.
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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 absolutely be avoiding if you have thyroid disease of any type.
How to Calculate "Optimal" Free T4, Free T3, & Reverse T3 Ratio:
Calculating these ratios is important because it can help you determine if your efforts are on the right track and whether or not your medications are working.
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Why does your Body even have Reverse T3?
That's a great question and answering it will help you understand why, in certain situations, your body will create too much of it.
Reverse T3 is meant to be there acting as a "Brake" on your metabolism (2) during times of EXTREME stress.
Let's look at chronic illness as an example:
When your body is recovering from an illness (like pneumonia or a bloodstream infection) does it make sense for your body to increase the metabolism and provide energy to your muscles?
Of course not! It makes more sense to conserve your energy and metabolism by SLOWING down energy production and providing energy to vital organs.
This is a protective mechanism built by your body and it may surprise you that it has a name and is well documented in the scientific literature.
It's knwon as euthyroid sick syndrome.
Patients that are under stress develop this condition which results in LOW Free T3 levels, HIGH Reverse T3 levels and NORMAL T4 and TSH levels.
Hmm... Does this sound like your lab results???
Despite the fact that EVERY Doctor has learned about euthyroid sick syndrome most believe that it's a phenomenon only seen in hospitalized patients.
But, we are seeing more and more, that patients with multiple chronic medical conditions present with the same lab tests as those who are hospitalized.
Studies like this one (3), shed light on the fact that other conditions, such as calorie-restricted diets, can lower free T3 levels and INCREASE Reverse T3 levels and cause changes in thyroid function that resemble "sick euthyroid syndrome".
Are you Pooling Reverse T3 in your body?
Now that you know you want Reverse T3 levels to be as LOW as possible the next thing you need to know is what CAUSES the high levels, to begin with.
Before we jump into the causes it's important to know how high reverse T3 tends to present from a symptom perspective (This can help you understand if it's even something you need to worry about).
As you might suspect, the higher Reverse T3 is in your body the lower your metabolism will be and the more weight you may gain.
Patients with high levels of Reverse T3 tend to have one or more of the following symptoms:
- Lower than normal metabolism
- Constant weight gain without changing eating habits
- Crushing fatigue
- Symptoms of hypothyroidism
- Chronic pain
- Depression, anxiety and/or bipolar disorder
These are the most common symptoms, but realize that each person presents in a different way.
For instance, I've seen people with high levels of reverse T3 present with the complete inability to lose weight and with severe depression.
If you have one or more of the following symptoms it's going to be VERY important for you to get your Reverse T3 levels checked and consider the treatment options below...
What causes elevated Reverse T3 levels, and what should you look out for?
In my experience these are the most common reasons that people have high levels of Reverse T3:
- Calorie-restricted dieting - Especially HCG diets or VLCD (very low-calorie diets). These diets (4) have been shown to reduce metabolism, increase reverse T3 and make permanent weight loss almost IMPOSSIBLE.
- Chronic illness and infections - This includes viral infections like infectious mononucleosis (5), bacterial overgrowth syndromes like SIBO and even chronic illness like cancer, cardiac/heart disease, arthritis, diabetes and even obesity itself.
- Chronic Inflammation - ANY cause of inflammation can result in decreased T4 to T3 conversion (6) and higher levels of Reverse T3. Inflammatory states include any untreated autoimmune disease, leptin resistance, insulin resistance, intestinal dysbiosis, cancer, etc.
- Chronic untreated Gut infections/Imbalances - Up to 20% of T4 (7) is converted to T3 in the gut, which means if you have gut issues you may be missing out on up to 1/5th of your conversion power. Gut imbalances include SIBO, dysbiosis, reflux/GERD, yeast overgrowth, history of chronic antibiotic use and inflammatory bowel disease.
- Emotional and physiological stressors - This includes social issues like the death of a loved one, family problems, divorce, etc. And it also includes trauma: psychological (PTSD) and physical (motor vehicle accidents, TBI or otherwise). Read more here. (8)
- Certain Medications - The most common medications causing elevated Reverse T3 include Blood pressure medications, diabetic medications, anti-seizure medications, narcotics, and antidepressants. A common example is the use of beta blockers which can be used to treat the symptoms of Hyperthyroidism (9) and they are commonly used to treat blood pressure (10).
I know, I know...
I said I wasn't going to get technical and I did anyway.
I apologize but it's important to know why many people are suffering from this issue. Chances are very high that you fit into one or more of the categories above and it's highly unlikely that anyone has ever looked at your Reverse T3 level.
Everything you need to know about Testing for Reverse T3
Luckily it's pretty straightforward to test for Reverse T3.
There is a serum marker for Reverse T3 that most standard lab companies can run.
The tricky part can be understanding and interpreting your results.
Before we talk about ranges you need to understand how these lab tests all fit together with one another:
One of the main reasons Doctors fail to recognize the importance of certain thyroid lab tests is that they look for thyroid studies in the "normal range" as opposed to the "optimal range".
If you haven't already please read this post which outlines the difference between being "normal" and being "optimal" as it relates to your hormones.
To start you will want to get a full thyroid lab panel which includes: TSH, Free T3, Free T4, Reverse T3, TSH and antibody levels.
As you can see from the image above, you can have high levels of Reverse T3 and most of your lab tests will likely not be outside of the "normal" reference range provided by the lab testing guidelines.
But this doesn't mean that your thyroid is necessarily working properly.
To determine if that is the case you will need to look at all of the tests and look at how they fit into the 'big picture'.
One of the most obvious changes to notice, in the image above, is the difference and spread between Reverse T3 levels and the Free T3 levels.
You can see that as Reverse T3 levels rise, free T3 levels will fall and this difference is the most dramatic when compared to the other thyroid lab tests.
For this reason, these two lab tests are critical evaluating thyroid function.
You can determine the "spread" between these two values with a simple calculation which will give you the ratio of reverse T3 to free T3.
In an ideal world, you want your Free T3 levels to be as high as possible (generally upper 1/2 to 1/3 of the "normal" reference range) and you want your Reverse T3 levels to be as low as possible.
This lab pattern allows for less competition at the cellular level and will allow for T3 to do its job.
In most patients, I find that a reverse T3 less than 15 to be ideal.
But remember that it's possible to have a "normal" Free T3 and VERY abnormal "reverse T3" which is why the ratio is so important.
To calculate your Free T3: Reverse T3 ratio simply divide the numbers.
Your ratio should be > 0.20.
Any ratio < 0.20 indicates TOO much reverse T3 to Free T3 and means that you should focus on either increasing your free T3 or reducing your reverse T3.
How to "Flush" Reverse T3 out of your body
You need to realize that treating your Reverse T3 problem is only effective if you treat the UNDERLYING cause. (11)
If your high levels of reverse T3 is secondary to insulin resistance and diabetes and you don't change your diet, then even with treatment your high levels will come right back.
For this reason, it's very important to find the underlying cause before you initiate treatment - because part of your treatment needs to be focused on that particular issue.
Having said that, there are definite ways to lower Reverse T3 levels quickly...
I've split treatment into 3 main categories:
1. Thyroid Medications to Reduce Reverse T3
The fastest and easiest way to get rid of excess Reverse T3 is with bioidentical hormone formulations that contain pure T3.
The reason this approach works so well is that when you give your body T3 hormone directly it suppresses T4 automatically which reduces the substrate that your body uses to create reverse T3.
Naturally what will happen with T3 supplementation is that your T4 levels will decrease, your Free T3 levels will increase and your TSH will drop.
While on T3 thyroid medication it's important to monitor Reverse T3 closely, at least once every 6 to 8 weeks.
Typically within 2 months (and assuming your dose of T3 is high enough) your reverse T3 should drop to less than 10.0.
As I mentioned above, this is by far the fastest way to reduce Reverse T3 - but it's important to still seek out and eliminate the CAUSE of your high reverse T3 levels otherwise they will just come back once you stop taking T3 medication.
You can find more information about T3 dosing in my weight loss and mastery guide where I have videos that walk you through the process (including how to titrate your dose, how to evaluate your labs and more).
NDT & Reverse T3 Levels
Can NDT be used to help flush out reverse T3 levels in the body?
It certainly can help but there are a few things to realize when trying to flush out reverse T3 levels while using NDT:
- Each grain of NDT has about 38mcg of T4 and 9 mcg of T3 - that means that NDT still primarily consists of T4.
- In order to flush out the reverse T3, you must lower the substrate of T4 which generally means lowering your total dose of T4, in most cases that means dropping your total dose of NDT
- NDT dosing is static meaning you can't individually alter the concentration of T4 and T3 unless you add medication to the NDT
With these considerations, and if you are on NDT but still experiencing high reverse t3, it's usually best to decrease your total dose of NDT and add T3 in addition to the NDT.
For most patients, dropping NDT down to 1-1.5 grains is usually sufficient.
But, remember this:
Simply manipulating the reverse T3 number by changing medications does NOT treat the cause of the elevated reverse T3, to begin with, and if you don't treat the underlying cause your levels will increase once you go back to your full dose of NDT.
2. Supplements to Enhance T4 to T3 conversion
In addition to medications, every thyroid patient should also consider utilizing nutritional supplements.
The reason is simple:
The hypothyroid state sets the body up for certain nutrient deficiencies and since most people are under-treated, most people also have these deficiencies.
Low thyroid = low stomach acid = decreased absorption of nutrients and puts you at increased risk for developing GI imbalances which further impairs absorption.
You can check out this post here for more info about which supplements you should consider using and how to check to see what your body needs.
When it comes to thyroid conversion we only want to focus on a few certain nutrients:
The two primary supplements that you should focus on are Zinc and Selenium. Both of these supplements have been shown in some clinical studies (12) to increase T4 to T3 conversion, thereby potentially decreasing reverse T3.
We aren't as concerned about supplements to promote thyroid production (such as Iodine and L-Tyrosine) because that isn't the problem with conversion issues (it may be for some but not for the majority).
If your Doctor isn't willing to change your medication you can check out this post for more info on how to naturally increase your Free T3 levels.
3. Reversing Hormones that promote T4 to Reverse T3 Conversion
As you are probably aware your hormones all work in tandem with one another.
This means that as one system slows down it may drag down other systems or cause an increase in other hormones to make up for the deficit.
This holds true with thyroid hormone and leptin/insulin levels.
The link between these three hormones is clear:
This is VERY important because hypothyroidism leads to a state where developing both insulin and leptin resistance becomes much easier.
Why do we care?
Because insulin and leptin resistance cause inflammatory states which contribute to T4 to reverse T3 conversion.
Not only do they cause high reverse T3 levels but they also make weight loss very difficult.
Is this sounding familiar now?
Patients with high reverse T3 levels almost always have high fasting insulin and high fasting leptin levels.
In fact, I have never seen a patient with a reverse T3 > 25 with a normal insulin/leptin level.
You can see examples from several patients above showing abnormal reverse T3 levels, high fasting leptin and high fasting insulin levels.
These values may fall within the "normal" range but they are far from normal and will lead to symptoms of hypothyroidism, weight gain and weight loss resistance.
Another big reason I want to talk about these hormone imbalances is that Doctors don't frequently run tests on either of these hormone imbalances.
Providers will check a Hgb A1c but rarely do they order fasting insulin and fasting leptin levels.
This means that if you have known high levels of reverse T3 (by the way, they don't always order this test either), it's probably going to be up to you to request these specific hormones.
Treating and reversing both insulin and leptin resistance is very important for not only lowering reverse T3 but maintaining low levels of reverse T3 over time.
To learn more about how I address these hormone imbalances (including treatment options) please see the following case studies below:
These case studies provide a step-by-step walkthrough of how to approach leptin and insulin resistance including medications, hormones, and supplements designed to help both conditions.
If you know you have insulin resistance then you can consider using these supplements to help lower your levels:
- Berberine: Helps reduce cholesterol, improve fasting glucose and may help with weight loss.
- Alpha Lipoic acid: Helps sensitize the body to insulin and may help to reduce nerve damage in certain patients
- Chromium: Helps improve insulin sensitivity to cells and may help reduce cardiovascular disease in certain patients.
If you prefer the natural approach to treating leptin levels you can find more info here on how to target supplements towards OTHER imbalances for the most benefit.
Most leptin supplements don't work unless they are used correctly.
4. Addressing Inflammatory Levels and "Cooling Off" Your Body
Everyone knows inflammation is bad for the body (15), but very few people understand how it makes things worse and more importantly how to treat it if present.
Part of the reason for this is because the markers we use for inflammation are non-specific.
That means most of the time we know inflammation is present, we just don't necessarily know where it is coming from.
Sure, in the presence of other abnormalities we might be able to take a guess, but we will rarely ever know with 100% certainty.
But how does inflammation relate to thyroid function and reverse T3 levels?
It turns out that inflammation directly promotes the production of Reverse T3 (16) from the substrate T4 resulting in high levels of Reverse T3 over time.
So if you have high reverse T3 levels you need to be actively searching for sources of inflammation and treating the cause directly.
How do you test for inflammation? Check the following blood tests...
- CRP: You want this to be as low as possible but definitely < 1.0 for optimal thyroid function
- ESR: Another non-specific marker of inflammation (17), for optimal thyroid function this should be < 10
- Ferritin: Both a marker for iron stores and an acute phase reactant (18) this marker can be used in certain instances to help isolate non-specific inflammation in the body
These are non-specific serum markers and may indicate that inflammation is present somewhere in the body.
If you know that you have both high levels of inflammation AND high levels of reverse T3 then you can safely assume that the inflammation is likely worsening your thyroid function.
The next step is to find where it's coming from.
In hypothyroid patients it's usually in these three places:
- Hormone imbalances (especially insulin and leptin resistance): Please refer to the section above to understand how to both diagnose and treat these conditions.
- Undiagnosed gut imbalances like SIBO and SIFO: Both of these gut issues promote inflammation (19) in the GI tract and lead to increased intestinal permeability. You can find more about both here.
- Undiagnosed food sensitivities: These sensitivities promote inflammation (20) and further food sensitivities unless treated.
If you have both high reverse T3 and elevated serum markers for inflammation you should be looking at the 3 main causes above and treating those if applicable.
If you don't know where the inflammation is coming from you can still do some good by taking supplements designed to help reduce inflammatory levels and promote the "clean up" of breakdown products in the liver:
- Milk Thistle + MSM: Designed to help improve liver function and promote proper phase 1 and phase 2 elimination of medications, supplements and other products that need elimination in the liver. May also help reduce AST and ALT levels (21)(if you have fatty liver).
- Krill oil + Astaxanthin: This powerful combination can help reduce inflammation by reducing inflammatory cytokines.
- Curcumin: This well studied herb activates PPAR-gamma levels (22) helping to reduce inflammation in the body.
- Quercetin + Bromelain: Particularly helpful in patients with digestive issues and those with chronic sinus/URI like symptoms (post nasal drip and chronic stuffy nose).
This approach isn't ideal but it's better than simply ignoring it.
Remember to work with your Doctor if you suspect you have an inflammatory process contributing to your high reverse T3 levels.
5. Lifestyle changes to Balance Hormones and Promote Thyroid Function
Never underestimate the power of these 4 major areas when it comes to your health:
- Getting 7-8 hours of quality sleep per night
- Reducing and managing your stress
- Daily low-intensity exercise and episodes of high-intensity exercise 1-3x per week
- And a balanced diet full of real, whole foods
If you don't practice these 4 basic things it doesn't matter what you do - you WON'T get better.
These are particularly important for those with high Reverse T3 levels.
Remember that your body is a NETWORK of systems and hormones that all interact with one another.
When one system isn't working properly, it will bring other systems down as well.
Often times boosting thyroid function with steps 1 and 2 above while improving these 4 areas is enough to bring balance back to other hormone systems.
That means you may find your menstrual cycle become more regular (as estrogen and progesterone balance), your belly fat to shrink (as cortisol level regulate) and your lean muscle mass increase (while testosterone levels out and insulin levels drop).
What about Low Reverse T3?
Though I didn't anticipate this would be a big question, people have been asking me about low reverse T3.
So let's talk about this for a second:
Is Low reverse T3 a bad thing? Does it need to be treated?
In order to answer these questions, we need to consider the function of reverse T3 and how it operates in the body.
If you have a state of low reverse T3 that means that there will be less competition for thyroid receptors at the cellular level.
This state will allow free T3 to bind to nuclear receptors and turn on genetic transcription which is exactly what you want to happen.
So, is having low reverse T3 a problem?
For a short period of time, I don't think that having low reverse T3 is a problem and, in fact, there may be reason to believe it's a good thing.
But like all good things, too much can be a problem.
Remember that reverse T3 is created by your body as a compensatory mechanism which is meant to throttle back thyroid hormone in times of need.
You don't want to completely shut off this system by FORCING reverse T3 as low as you can go for an indefinite amount of time.
Instead, a better approach is to "flush" the system out, lower reverse T3 levels for a short period of time, and then allow your body to naturally balance out T3 and reverse T3 levels.
Persistently low levels of reverse T3 may cause hyperthyroid symptoms if left suppressed for a long duration of time.
High levels of Reverse T3 can be a very serious issue for many thyroid patients and may help explain why you've been consistently symptomatic and resistant to weight loss despite taking thyroid medication.
In order to diagnose high levels of Reverse T3 and thyroid resistance, you need to look at both serum levels of Reverse T3 and Free T3.
Measure your ratio of these hormones (as this is the most sensitive marker for tissue levels of thyroid hormone). If your Free T3/Reverse T3 ratio is < 0.2 you have TOO much Reverse T3 in your body.
The best treatment for reducing these levels is by taking pure T3 thyroid medication, taking supplements to increase T4 to T3 conversion and by making the appropriate lifestyle changes to balance other hormones in your body.
Doing these things will finally help your body get back into balance and get RID of your hypothyroid symptoms.
Now I want to hear from you:
Do you have too much Reverse T3 in your body?
Have you tried pure T3 medications like Liothyronine or Cytomel?
Did they work for you?
Leave your comments below!
References (Click to Expand)
This post was most recently updated on November 8th, 2019