The Thyroid Test You’re Not Getting (But Should Be)

Beyond the Thyroid – Episode 29: The Thyroid Test You’re Not Getting (But Should Be)

If you’ve been told your thyroid labs are “normal” but still feel tired, foggy, or unable to lose weight—this episode is for you.

In Episode 29 of Beyond the Thyroid, Dr. Dana Gibbs uncovers the total T3 to reverse T3 (T3/RT3) ratio—a powerful but overlooked marker that can reveal hidden thyroid dysfunction. She explains how this ratio offers insights that standard labs often miss, especially in patients with chronic fatigue, weight issues, or brain fog.

You’ll learn how chronic stress, inflammation, and poor sleep can skew this ratio and what steps you can take to correct it. Dr. Gibbs also introduces her new Thyroid Clarity Checkup program, designed to help patients uncover the real cause of their symptoms and get on a path to true healing.

📑 Join the The Thyroid Clarity Checkup Priority List! 

🩺 Interested in a Discovery Call with Dr. Dana? Click here!

📺 Watch on YouTube

Episode Highlights:

00:04 Understanding the T3/Reverse T3 Ratio
01:17 Personal Journey and Expertise
01:39 Introducing the Thyroid Clarity Checkup
02:10 Welcome to Beyond the Thyroid Podcast
03:21 Common Thyroid Testing Issues
03:57 Case Study: Lisa's Thyroid Journey
04:48 Why the T3/RT3 Ratio Matters
08:18 Factors Affecting the T3/RT3 Ratio
19:00 Practical Tips for Thyroid Management
22:18 Thyroid Clarity Checkup Program Details
24:17 Conclusion and Final Thoughts

Let's connect! 🔔
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Tiktok - @dana.gibbs.md

✉️ Email Dr. Gibbs at drgibbs@DanaGibbsMD.com or visit https://www.danagibbsmd.com/ for more information.


Thank you so much for listening! Tune in on the next episode.


The medical information provided in this episode is intended for informational purposes only and should not be construed as medical advice. Always consult a qualified healthcare provider regarding any medical questions or concerns.

Transcript

dana-gibbs-md--she-_6_06-02-2025_150626 0:02

Welcome to episode 29. Today on the podcast, I'm gonna discuss the most important marker that I use in thyroid practice, and that is the T3 reverse T3 ratio and why it might be the real thyroid test you're not getting but should be. Physicians in the thyroid research space are realizing that there are a subset of people with hypothyroidism whose troubles are not adequately explained with the current mainstream way of testing. That is the TSH test with reflex to T4. There are people who don't adequately respond to levothyroxine in therapy. So these doctors even admit that a sizable proportion of patients who are diagnosed respond better to thyroid medicines that contain T3, the active form of thyroid hormone. And yet, they don't know how or even when to offer these medications because they don't adequately understand reverse T3 and thyroid signaling. So come take a listen as I break down just what is reverse T3, how it informs the science based and judicious use of T3 containing medicines to safely get people feeling well, not just making their labs look better. So my approach is informed by years of combined medical experience, extensive literature searches. And although my interest in this field was started by my personal experience of undiagnosed hypothyroidism 20 years ago, I have continued to learn more and more about this topic basically every day. Before we get started, I'm offering a brand new signature program for people who aren't sure that their thyroid is actually what's causing their symptoms and wanna get testing and analysis without the high price point of a comprehensive one-on-one evaluation or an expensive coaching program. I'm calling this the Thyroid Clarity Checkup and more information and the signup page is available at www.danagibbsmd.com/checkup. So let's get into this.

2:20

You're listening to the Beyond the Thyroid podcast. I'm your host, Dr. Dana Gibbs. I'm an ENT surgeon and hormone specialist. For years, I struggled with my own unrecognized thyroid problems before and even after I was regularly performing thyroid surgeries. Then, one day, I learned something that turned my health around and opened my eyes to the limits of mainstream medicine in treating more subtle thyroid abnormalities. I spent the next 20 years fine tuning my hormone expertise in disorders like Hashimoto's disease, perimenopause, and stress related illness. Come join me as I share this new approach to hormones that empowers you to take control of your own thyroid and hormone imbalances. Let's dive in.

dana-gibbs-md--she-_8_06-02-2025_151028 3:12

Hello, my friend. I am so happy to have you here, and if you're new to the podcast, welcome. Let's get started with today's topic. Let's start with this. Most thyroid tests run in conventional offices. Medical offices only measure TSH and sometimes free T4. If your TSH is really outta whack, and if you're really lucky, maybe free T3, but what happens when those numbers are normal and you still feel off?, that's where the total T3 to reverse T3 ratio comes in. I find this test to be one of the most useful and precise indicators of whether thyroid hormone is actually working where it counts in your cells, and yet no one is running this. So, take Lisa, she has a pretty common scenario for patients who come to my clinic. She's a doctor too. She works hard at her high stress job. She has a family and kids and is trying to do all the things, but she's tired. She has many other symptoms of low thyroid like loss of hair, irregular periods, libido problems. She and her primary physician have tried lots of things, including antidepressants and even ADHD medicines to help her with their brain fog and got little results when I've got her labs, the only thyroid lab that shows abnormal is the reverse T3 and the total T3 reverse T3 ratio. But starting her on the right dose of thyroid medicine had a profound effect on how she feels, and it made her thyroid numbers look better within only a few months. So today I'm gonna explain to you guys why the T3/RT3 ratio is more accurate than TSH or even free T alone. What causes this value to be off? Why we also look at free T3, free T4 and TSH, but in context, and I'll sprinkle in a few real world fixes for patients who are already on levothyroxine who still don't feel well that you could try right now. So why is this T3, reverse T3 ratio so useful? So. It has to do with the fact that T3 is the active thyroid hormone. It is what actually turns on the energy and the metabolism and the cellular functions that you need to feel alert and alive. But here's the catch. Your body can block T3 function by converting T4 into something called reverse T3. This is a molecule that looks almost identical. But does not activate the thyroid receptor the way T3 does. It's like a key that's made improperly and fits into the lock, but it just doesn't quite turn and worse, it blocks the good key from doing its job. So if you wanna understand what's happening really in your tissues, you don't just look at how much T3 you have, you also look at how much of it is getting blocked or inactivated. That's why this total T3 to reverse T3 ratio is so essential. So if the ratio is under 10, that's a strong signal that your body is inactivating TT4 thyroid hormone instead of turning it into active T3. There are several reasons why this happens, which we're gonna discuss in a minute, but even a mid-range ratio like eight can correlate with symptoms in really sensitive individuals. And I have seen this ratio be terrible, like as low as two and a half in people who felt to terrible but still had a normal TSH normal free T3 and a normal free T4. If the ratio is over 14, it may be a sign that things are also not balanced properly. So that's the T3/RT3 Ratio. How do you get the ratio? Well, it's pretty easy or order a total T3 and you order a reverse T3 and you do long division. You divide one into the other and you get a number, and the number will be between usually 2 and about 20. But normal is 10 to 14. And here's the critical thing comparing free T3 to reverse T3 does not work. Reverse T3 is measured as a total, not a free faction. It's not even apples to oranges. It's more like apples to bowling balls. The only meaningful comparison is total T3 to reverse T3. I see a lot of patients who've been to other quote unquote"thyroid literate practitioners" who've gotten this wrong, and it's really sad because they think they're getting the best of the best, but they've had misinterpreted labs, suboptimal treatment, and sometimes even bad side effects from taking the wrong combination of thyroid medicine at the wrong time. So, we don't guess we test properly and we interpret based on physiology as well as symptoms. So what kind of things cause the T3/RT3 ratio to be abnormal? Well, there's several things that can skew that ratio, and they often overlap with one another. So let's talk about the most common ones. The absolute most common one is chronic stress. Why?'cause chronic stress causes elevated cortisol hormone in your blood. Elevated cortisol does a bunch of not good things in your body, including pushing an abnormal TSH down into the normal range so that it doesn't look abnormal, even though you don't have enough thyroid hormone. But the second thing it does is it skews your body towards making too much reverse T3. The second thing that it does, and this is high cortisol again is pushing your immune system towards autoimmune disease and inflammatory diseases like allergy. So it's doing that at the same time as it's pushing down on the TSH. And what that does is because of all that inflammation, it pushes the cortisol up even more. Several other things like nutrient deficiencies, particularly iron, zinc, and selenium can cause abnormal ratios of T3 and RT3. Here's another one, crash dieting or repeated calorie restriction. This is another version basically of chronic stress. Your body thinks you're starving, so it ramps up your cortisol and the cortisol turns around and pushes up on reverse T3 and down on T3 and messes up that ratio. Here's another one, prolonged fasting, same reason your body thinks you're starving. Another one is over exercising. When you exercise too hard without allowing your body to recover, you keep your cortisol levels very, very high, and those high cortisol levels, once again, have a chemical force on your thyroid metabolism making you make too much reverse. T3. If you don't check that T3, reverse T3 ratio, you might never know because everything else can look completely fine. Poor sleep, huge, huge. If you're getting less than seven hours of sleep a night, it is very, very likely that you will have that elevated reverse T3 and a low T3/RT3 ratio. There are also certain medications such as beta blockers and some antidepressants and chemotherapies that can do the same thing. And then the final one is genetic abnormalities in the gene that makes the enzyme that makes T3. If you have this. It's called a SNP, a single nucleotide polymorphism. If you have a SNP in your deiodinase part type two gene, you will make too much reverse T3 and not enough T3. So one other completely overlooked cause is once daily dosing of levothyroxine. Here's why. When you take your full dose of levothyroxine in the morning and levothyroxine is T4. T4 is the by is the product that is used to make the T3. So if you have your full dose all at once in the day, your blood level of that T4 will spike up for abouT3 hours. Frequently triggering your body to convert more of your T4 into reverse T3 than anybody knows this happens because your cells interpret that spike as too much hormone and try to shut down thyroid metabolism to protect your body from hyperthyroidism, which is too much. And most doctors do not recognize that you have very high blood levels for a couple of hours after you take levothyroxine or any thyroid hormone, your blood levels are really, really high. So one simple fix for this is to chop that levothyroxine dose in half and take half in the morning and half in the afternoon, or maybe even right at bedtime. What this does is because you're taking less at a time, that spike that you get right after you take the pill is basically half as high as it would be if you took it all at once. So you get two spikes, but they're much smaller. This makes the blood levels more even and reduces that stimulation to make too much reverse T3. So it helps your body be more balanced. So here's another thing, most doctors really don't give any advice at all about when you ought to get your thyroid labs drawn, but in my experience, it's very, very essential to take your thyroid medicine at the same time every day, and then have your labs drawn at the same time of day every time you go to the lab. This is because when you're taking your thyroid medicine, as we talked about just a second ago, your blood levels can vary as much as 30% from the time, two hours after you took it to the time right before you take it again. And that's even if you're taking the thyroid medicine more than once a day, which I do recommend. As far as the ideal time to get your labs done, doctors also disagree about that. Many doctors wanna see your labs first thing in the morning before you take your thyroid medicine. This may give you consistency, but then we're only seeing a time when your thyroid medicine is at its lowest. In medicine, this way of testing is called a trough. And it's great when we don't want your blood levels of whatever the drug is to go lower than a certain amount, but it misses that peak, that point, a couple hours after you swallow the pill, when the blood level might be the highest, and in fact, too high and triggering reverse T3, it might technically be an overdose. In my clinic, we wait and test about six hours after you take your morning thyroid dose. So if you take your medicine, at 12 hours apart, so say 7 in the morning and 7PM then you would go at 1PM, so six hours after. If you take your thyroid medicine three times a day or every eight hours, then you would go four hours after you take your earliest morning dose. That way we get the clearest possible picture of your thyroid levels and we test it the same way, every time. All right. TSH, T4 and T3 still matter, but they're not enough. So, the TSH tells us about the signals. That our brain and our pituitary gland are sending to the thyroid gland. So low tSH usually means that your brain and your pituitary gland are detecting too much thyroid hormone in your system, and the stimulus for more thyroid hormone is gonna slow down. That's lower TSH. Free T4 shows how much of that pre hormone T4 is in your blood. Free T3 tells us the same, how much T3 is floating around in your blood. There has been some argument that said these free blood hormone levels shouldn't be tested because they don't show us what's happening in your tissues. But really detailed research shows that the blood tests are actually a pretty accurate representation of the levels in your tissues because they equilibrate, they flow back and forth across the membranes. But none of these alone tell us how well your tissues are using what is there? Are the tissues getting enough? Are they getting too much? That's where that T3 reverse T3 ratio matters so much because it gives us insight into receptor level signaling. Still, I always look at those other standard labs because they give us valuable context. For example, a free T3 of 2.8 might be in the normal range. But if the total T3, reverse T3 ratio is down around six instead of the ideal 12, that's a problem. It means you don't actually have enough T3 compared to your reverse T3. If TSH is down. Free T3 and free T4 are also low. Then we really need to look deeper and figure out what's going on with your thyroid. Because you could have a pituitary problem. You could have an adrenal problem that is making those things too low. You could have one of these stress related situations that I talked about just a minute ago. So it's all about interpreting the whole picture, not just chasing a single number. Now let's talk about thyroid antibodies, because I don't check Hashimoto's antibodies every time I check someone's thyroid hormone numbers. So once you know whether you have Hashimoto's, your antibody levels can be really, really high, or they can be fairly low and high antibody levels are important because they tend to indicate the overall level of inflammation that you have in your body and the progression of damage that's currently happening to your thyroid gland and the chance of developing another autoimmune disease in the future. So it is a good measure of how well your lifestyle measures are working to lower inflammation in your body, but they don't say much, if anything, about how much, or even if a person needs thyroid replacement right now because they don't reflect thyroid signaling. Although high thyroid antibody levels do tend to worsen thyroid signaling. So, unless there's a new concern, I don't recheck those more than maybe once a year to see how your lifestyle measures are working, but I check that TT3/RT3 ratio fairly frequently. Basically after every time I adjust the medication, and then every few months after that, because that TT3/RT3 ratio will change with your stress, with your sleep, with your infections, with your diet, and the status of other hormones in your body. So it tells me what's happening right now and how your metabolism is functioning in real time. So, what to do first, if you're on levothyroxine and you still feel terrible, I see this every week. Patients come in on Synthroid or another form of levothyroxine, their TSH is normal. Their doctor has said nothing wrong with your thyroid, but they still feel exhausted. So if that's you, here's two steps that I recommend to start, even before you get your next set of labs. Number one, split your thyroid tablet in half. Take half in the morning, half in the evening. Take the first half right when you normally wake up. Don't wake up at 4:00 AM to take thyroid meds fasting, the loss of sleep is terrible for thyroid function, but once you take your thyroid meds in the morning, take it when you normally wake up. Try not to eat for about half an hour, but don't skip breakfast because of taking thyroid medicine that is really bad for your metabolism. You can take that second half dose either an hour before dinner or right as you're headed to bed. If you forget, take it as soon as you remember, regardless of whether you just ate or not. Remember, the point of this is to lower the dosage spike that you would be getting if you took it all at once in the morning. So the advice to wait two hours before or two hours after the medication to take it, to take food is less critical than when you take it The next thing I advise folks to do is keep a symptom diary. As you begin to do this, every change that you make should be recorded and given a week or maybe longer, to take effect before you either go back to the previous dose or add something else. Some things like diet changes take even a little bit longer to notice an effect. The third thing that I strongly recommend that everybody who is suspicious of thyroid problems do or who is on thyroid medicine is check your thyroid labs at the same time of day every time. Ideally, six hours after you take that morning pill. This gives us a steady level number. Remember, your level can vary 30% at different times a day depending on when you take your pill, and that will stop your doctor chasing your levels up and down and changing your medication repeatedly. This may mean that you need to do your thyroid labs separate from your regular fasting metabolic labs like cholesterol and blood sugar that have to be done early in the morning with no food. Yes, I agree it is more trouble. But it's worth it. And then the last thing is ask your doctor to order these five lab tests, TSH, total T3, free T3, free T4, and reverse T3. If they won't order this, you can now order and pay for your own labs without a doctor's order, but it won't be covered by insurance depending on where you go these tests can be as low as$120, but really you shouldn't ever have to pay more than$200. So if this sounds like something you really need to figure out, I do wanna tell you again about my group training program that's coming up. It's called the Thyroid Clarity Checkup. So ordinarily when I see a new patient one-on-one, it involves a lot of time, a lot of detailed questionnaires and extensive review of records, and that's before we even get to our face-to-face visits. It's a lot to go through and it can get pretty expensive, but this method of checking your thyroid can get the answer,"is this a thyroid problem or isn't it", pretty quickly? So I wanna get this amazing method into the hands of more people who need it. So the thyroid clarity checkup is designed to answer two questions. Do I actually have a thyroid imbalance? And what do I need to do next to fix it? So getting that clarity can be such a relief. Especially after years of frustration and exhaustion being dismissed because your TSH isn't bad enough, or being led on by so-called thyroid experts who don't understand the science and can't prescribe the medications you actually need. So in this program, I'll help you get exactly the labs you need. I'll show you how I analyze them. I'll review your history, help you get started toward the right treatment regimen. I'll even meet with the participants one-on-one to go over everything and answer questions in the pilot program, which is starting soon. So go to www.danagibbsmd.com/checkup right now to get more information and save your spot on the priority wait list. I expect this program to sell out pretty quickly, so don't delay. I'll be opening the applications very soon. So imagine understanding exactly what your thyroid labs mean. Imagine seeing your symptoms validated and knowing there's a scientific reason for how you feel and that you can fix it. That's the power of precision testing. That's what we do here at Beyond the Thyroid. Thanks for joining me today. I'll see you next time.

24:27

Thank you for listening to this episode of Beyond the Thyroid. If you found this information valuable, it would mean so much to me to take a few seconds and give the podcast a five star review. It helps other people who need this information find the show and it's really easy. Just search and click on the name of the show, Beyond the Thyroid, and scroll to the bottom to ratings and reviews. I truly do read and appreciate. Remember, when it comes to hormones, there will always be more to discover, so follow the show so you get the next episode as soon as it's released. And if you or someone you care about needs a caring doctor to help figure out how to heal hormone problems that other doctors have dismissed, check out my website at www. danagibbsmd. com. And if you're not a physician, please keep in mind, while I'm a doctor, I'm not your doctor. The content of this podcast is my opinion and it's for educational and entertainment purposes only. This is not meant to be individual medical advice and you should consult your own physician for any medical issues or diagnoses that you may have. I look forward to continuing this journey with you beyond the thyroid.