Think It's Your Thyroid? Midlife Fatigue, Weight Gain, and the Myths Behind "Normal" Labs

One in four women will have some degree of thyroid dysfunction after menopause — so it's not unreasonable to test it. But Dr. Komal Patil-Sisodia says the real problem isn't whether we test, it's what we do (or don't do) after the results come back "normal." In this episode, she breaks down the most common thyroid myths she hears in clinic: that fatigue and weight gain automatically mean thyroid disease, that everyone needs a full thyroid panel, and that a slightly elevated TSH always means you need medication. She walks through what TSH actually measures, when free T4 and T3 testing adds value, why antibody testing isn't a default screen, and the real risks of over-treating with levothyroxine. Then she dives into the part almost no one explains: how perimenopause and menopause change the way we interpret thyroid labs, why your TSH reference range shifts with age, and how starting estrogen therapy can change your thyroid medication needs.

Timestamps

• 00:00 — Welcome to Clearly Hormonal
• 01:03 — Is It Really Thyroid?
• 02:27 — Myth 1: Symptoms Automatically Equal Thyroid Disease
• 05:22 — Myth 2: Everyone Needs a Full Thyroid Panel
• 06:04 How TSH Testing Works
• 11:18 — When Extra Testing Actually Matters (pituitary, pregnancy, illness, med changes)
• 18:32 — Thyroid Antibodies: What They Are and When to Check Them
• 19:45 — Myth 3: Subclinical Hypothyroidism Always Needs Treatment
• 23:07 — The Real Risks of Overtreatment (and What the Evidence Shows)
• 26:56 — The Menopause–Thyroid Overlap No One Explains
• 30:51 — How Estrogen Therapy Changes Your Thyroid Labs
• 33:37 — Questions to Ask Your Doctor
• 35:21 — Next Episode Preview & Wrap-Up

Resources & Studies Mentioned

• 2017 TRUST Trial (New England Journal of Medicine) — levothyroxine vs. placebo in adults 65+
• 2025 Annals of Internal Medicine analysis of NHANES data on age/sex/race-specific TSH ranges
• 2026 Hong Kong population study on age- and sex-specific TSH reference ranges
• Korean cohort study of 50,000+ women on thyroid dysfunction across the menopause transition
• JAMA study on successful levothyroxine discontinuation in older adults on low-dose therapy

Connect

• Instagram & TikTok: @drpatilsisodia
• Podcast: Clearly Hormonal
• Practice: eastsidemm.com
• If this episode resonated, share it with a woman in your life who’s been searching for answers. Leave a review so more women can find this podcast.

Disclaimer: This podcast is for educational purposes only and is not a substitute for personalized medical advice. Please discuss your own labs and symptoms with your healthcare team.

Thanks for listening. Find more info about Clearly Hormonal on the website or Instagram.

Transcript

Dr. Komal Patil-Sisodia 0:01

Welcome to Clearly Hormonal, the podcast where we stop googling our symptoms at midnight and actually start understanding what's going on in our bodies. I'm Dr. Komal Patil-Sisodia, an endocrinologist, internist, obesity medicine specialist, and a Menopause Society certified practitioner, which is really just a whole lot of words to say hormones are kind of my jam. I've spent 17 years watching women try to navigate their hormonal health without ever having been taught the language for what's happening in their own bodies, and then meeting clinicians who want nothing more than to help them figure it out, but are up against 10-minute appointments and a system that just wasn't built for it. This podcast is my answer to that gap. We'll cover menopause, metabolism, hormones, and everything in between with real evidence, not trends, and without the overwhelm. A quick disclaimer: I'm a physician, but this is education, not personalized medical advice. Take what resonates and discuss it with your own healthcare team. Now, let's get into it and talk about what's clearly hormonal and what's not. How many of you have ever wondered whether you have a thyroid condition? I know I've been guilty of this, and what I see very commonly in my practice is women come in wondering if they have a thyroid condition when truly it is something else entirely. And today's episode is going to focus on why your thyroid is not the only explanation for your symptoms. I very frequently see women who are in their mid-40s, sometimes even late 30s, and they're feeling exhausted and cold when everyone else is warm, and they can't lose weight despite doing everything right. I've been in that situation, and I've asked my doctor to check my thyroid, but then the thyroid test comes back totally normal, and we're often told to sleep more and stress less, and then we leave the office with not really having much of a plan. And a lot of us will spend time wondering, "Gosh, is it in my head? Like, what is actually going on?" So today, I want to talk about the most tested, most Googled, most misunderstood gland in the female body, the thyroid gland. And I want to start by telling you something that could be uncomfortable. Most of the time, when a woman comes to me convinced that it's their thyroid, it isn't. But that doesn't mean nothing's wrong. It means we've been asking the wrong questions. So let's talk about the first myth that I want to dispel, which is fatigue and weight gain mean you automatically have thyroid disease. And I see this myth everywhere. Hypothyroidism's Textbook symptoms, the ones that we learn about in medical school, are things like fatigue, weight gain, cold intolerance, brain fog, hair loss. And if you Google, like, that's the first thing that will pop up, thyroid, thyroid, thyroid. And thyroid is the most tested endocrine organ in primary care because when it's the right diagnosis, it's something that's easily fixable and can actually alleviate a lot of these symptoms. And it's interesting because the labs are now starting to do these direct-to-consumer lab tests, so people are testing their own thyroid. I've had a few patients show up, and I don't see that they've done my labs in the system, but they're like, "Oh, no, no, no, I just ordered my own thyroid labs through this other lab, and I got them done." What I actually want to talk about is whether you need this testing or not, right? It's not that you shouldn't get tested. In fact, one in four women will have some degree of thyroid dysfunction postmenopausally, and that's, like, 25% of us, right? So it's not unreasonable to check it, but when the tests come back normal, it's reasonable to do a little bit more and ask more questions Fatigue and weight gain are generally the most common presenting symptoms of thyroid disease. And most people with these symptoms should get tested. This is appropriate and reasonable. And the myth isn't that the testing is wrong. The myth is the assumption that these symptoms automatically equal thyroid disease. And the related myth is that a normal thyroid result means the search is over. Fatigue and weight gain are two of the most common and non-specific symptoms we have in medicine, and the majority of patients who present with those symptoms don't actually have hypothyroidism. In fact, when I test people, more often than not, the levels come back normal. So definitely go get tested. That part is right. And the US Preventative Services Task Force guidance basically says we shouldn't screen everybody if they're asymptomatic, but if you're having symptoms, you should get screened. But if the labs come back normal, it's not the end of the workup. There is still something causing your fatigue and weight gain, and we need to find out what that is. So in midlife women, what I commonly see is that the normal thyroid labs plus fatigue and weight gain are commonly due to things like perimenopause, insulin resistance, or sleep disruption from perimenopause, menopause symptoms. So getting tested is the right move. Stopping when the labs are normal is the mistake. A normal thyroid panel doesn't mean nothing is wrong. It just means that nothing is wrong with the thyroid, and we gotta keep looking. So now let's talk about myth number two, which is everyone needs a full thyroid panel, and this one drives me bananas because this myth goes in, like, the opposite direction of myth one, this is a common thing that I hear in wellness and functional medicine spaces, where getting a full panel has become default advice. And I think that's wrong because it creates more questions than it does answers. And I want to talk a little bit about what the guidelines say, the ones that are based in science and evidence and research. For the vast majority of, people who are in that outpatient setting who are being evaluated for primary thyroid disease, TSH alone is the initial recommended test. And let's talk about why that is., TSH stands for thyroid-stimulating hormone, which is a hormone that is released from the pituitary gland. The pituitary gland is the center in your brain that controls the hormonal action of the adrenals, the thyroid, the testes, and the ovaries. It can also produce other hormones that regulate salt and water balance, like desmopressin or prolactin, which is crucial for breastfeeding. The pituitary does a lot. I call it almost like the remote control of the endocrine organs in our body. For the thyroid specifically, the pituitary gland will release TSH, which stands for thyroid-stimulating hormone. And if we look at the general majority of people, most people will have dysfunction or disease that originates in their thyroid gland, not in their pituitary. And finding a pituitary tumor that's disrupting TSH is much less common than finding something going wrong with your thyroid gland. So, the first and best test tends to be the TSH. And if the TSH is off, either too high or too low, then we do additional testing to figure out whether there's something else that could be going on, either in the thyroid or very rarely in the pituitary gland. When we're evaluating whether a lab test is a good starting test, we always look at two things, sensitivity, which rules a disease out, and then specificity, which rules a disease in. Meaning, is the test sensitive and specific enough in order to do that? And for a TSH, it's important to note that the sensitivity is ninety-eight percent and the specificity is ninety-two percent for detecting thyroid function. Those are pretty good odds. So a two percent chance that you didn't rule it out versus an eight percent chance that you didn't rule it in, like, those are pretty good odds when we look at overall lab testing. Guidelines from the American Association of Clinical Endocrinologists and the American Thyroid Association are very clear when they state if TSH is within the normal reference range and you don't suspect that something is going on in the pituitary gland, measuring free thyroid hormones like free T4, free T3, they don't actually add any further relevant information. And the reason why is that free T4 and free T3 are in constant flux. Those are the thyroid hormones that your thyroid gland, is producing. Your thyroid gland produces ninety percent T4, which I always call that, like, the savings account of your thyroid, right? That's the cash that you put aside for a rainy day, and it gets activated to T3 when your body and the different tissues need to use it. Now, your thyroid gland makes about ten percent T3 'cause you gotta have some that you can pull on in a pinch, and I call that the checking account. But every tissue in your body has these enzymes called deiodinases, and they're called that because thyroid hormone's made out of iodine molecules. And T4 has four iodine molecules, and T3 has three iodine molecules. And because each tissue is metabolically active at a different rate, how much T3 you need in each different tissue is going to vary. That's why our body is so smart. That's why we have these deiodinase enzymes that are present within different tissues so that it can work on that conversion process of turning T4 into T3 so that that particular organ system can use it. And when I say organ systems are metabolically active at different rates, I'm going to give, a very basic example. We think about our heart and our cardiovascular system. Our heart is very active. It's continuously pumping blood through our body. All of the arteries and veins have to take it to the end tissues and back. And so it is a very active system. Versus think of your skin as an organ. Our skin is not as visually metabolically active as our heart is. So it may need less T3 than the heart system to continue functioning. And so because each tissue in our body is so fine-tuned, the T4 and T3 that we measure in our bloodstream is not actually indicative of what might be going on at a tissue level, like what's actually happening in the tissues of the heart or what's happening in the skin for T4 and T3. So they're not really the most reliable markers, and I think continually testing those because they are fluctuating up and down depending on what's going on in your body, it can create a really confusing picture, and people can get diagnoses that are not necessarily true. So doing a full panel, right, to include all the free hormone levels, it doesn't always necessarily help. And honestly, as an endocrinologist, when I'm looking at it, if those levels are in the normal range for the most part, or even if they aren't and the TSH is normal, I will have a discussion kind of based around that that's a little bit more nuanced There are a few scenarios in which we want to know these things. So if the TSH is elevated, we want to know the free T4 level because the free T4 level, if it is normal or low, indicates to us whether there is what we call overt hypothyroidism, meaning this is obvious hypothyroidism because the T4 is low and we don't have enough circulating in the system, or what we call subclinical hypothyroidism, meaning you can have a normal free T4, but the TSH is above the reference range. And if the TSH is low, for example, then we look at free T4 and free T3 to look at whether somebody has hyperthyroidism. Because TSH is the signal going from your brain to the thyroid gland to make it produce thyroid hormone. The two main scenarios in which it might be too high or too low, are hypothyroidism and hyperthyroidism. Think about your brain like a mom who is waiting for a call from their kid, right? And if the kid is not calling, so think of that as like the thyroid not making enough thyroid hormone, the mom is getting increasingly worried, like the pituitary gland is getting increasingly worried that there's not enough thyroid hormone in circulation. And so it starts sending out a signal rapidly to try and get in touch with the thyroid, and that's why the TSH goes up. It's the same way like a mom would keep calling their kid if they're not hearing from them within a certain timeframe, right? Now, on the flip side, think about it like the thyroid gland is super overactive, so it's overproducing thyroid hormone. And I always think about this like when a kiddo wants something from their parents, right? Like they want a new toy or they want something that has caught their attention and they keep asking again and again and again and again. And the mom, in this case the pituitary gland, is like, "Oh my gosh, there's too much going on," and they kind of shut down their communication a little bit. So this is the mom hiding in the pantry just trying to get a moment of peace while their toddler is asking why a million times or I want this a million times, right? And again, I'm being facetious with these descriptions, but sometimes it helps to visualize how that system works so that you can understand why we do the testing that we do. Now, when the pituitary gland doesn't work, then the tests are not as predictable as what I just described. The scenarios that I just described to you are as if your pituitary gland is working perfectly. However, there are things that can affect the pituitary gland, just like there are things that can affect the thyroid gland. The most common thing we see is if there is a growth in the pituitary gland that is affecting how the cells function in that area. You can have issues with your thyroid. You can have issues with your adrenals. You can have issues with the estrogen and testosterone coming from the ovaries and the testes. So if we suspect what we call central or secondary hypothyroidism because something's wrong with the pituitary, then we need to do additional testing. And free T4 will really help us because if the TSH is low, meaning the pituitary isn't producing enough, and the free T4 is low, then we worry that there's something going on in the pituitary gland. And in patients that I see that in, I will scan their head with an MRI to make sure that there's not a tumor there Now, other scenarios where these tests cannot fall into those regular patterns will be pregnancy. In pregnancy, the reference ranges for what is a normal TSH and what is a normal T4 are very different than what they are in non-pregnant individuals. And then in acute illness, so say you're sick enough to be hospitalized or put in the ICU, because thyroid hormone is an active hormone and it's constantly putting you in this state of being able to metabolize, your body actually wants you to heal and slow down. And so the thyroid tests actually become very unpredictable. And there's this condition called non-thyroidal illness that can either transiently increase or decrease the amount of thyroid hormone, that can either transiently decrease or increase the amount of TSH. And the free T4 and free T3 levels can also be affected depending on what the body needs in that stage. And we call that, non-thyroidal illness or euthyroid sick was the old term. And a lot of times what we'll do is if we think it is all due to illness, we let the illness resolve before we put people on treatment. I've seen people get started on thyroid medication or anti-thyroid medication when they're in the hospital, and it really causes some issues for them when they get out because their thyroid function was actually fine. It just looked a little funny because they were sick. So if you're sick, you don't want to get your thyroid levels tested during that time. You want to wait two to four weeks after the illness has resolved, usually four. That tends to be my preference. So we can actually see if there is something going on with your thyroid. And then early in treatment changes, right, when we change your medication and we're looking to see how that's working, sometimes the tests don't catch up to what we're giving you. So that will be why your doctor tells you you can't have your thyroid test checked every week or every two weeks because the And that's why your doctor will tell you it's not reasonable to check thyroid tests every week or every two weeks. We'll usually wait every four to six weeks to give all of the tests time to settle and the new dose to build up in your system. Usually, it takes three to four weeks for a dose change to show itself, so I like to wait four to six weeks before repeating labs. Really, ideally, it would be three months because that really gives your body some time to settle into that dose. But that tends to be the recommendation from the endocrine societies. Now, a lot of people will ask me, "Why aren't you checking my free T3?" And when the studies were done and they looked at whether T3 was helpful in the diagnosis of hypothyroidism, the answer is it's not. It does not add anything to the diagnosis. We will still treat you. And like we talked about before, just because your T3 is a little low in that moment doesn't mean that you need T3 supplementation because you could check it, like, two days later and it could be in the normal range. So we don't base things off of just T3 because that doesn't necessarily make sense in how we treat people. Free T3, however, is useful when we're trying to diagnose hyperthyroidism, right? So if the TSH is low and we check a free T4 and a free T3, if those are elevated, that tells us that your thyroid gland is overproducing thyroid hormone, and it's very helpful in making the diagnosis of hyperthyroidism. And sometimes, it can be helpful in differentiating which type of hyperthyroidism you have. Now, in terms of thyroid antibodies, there's not any specific guidance around thyroid antibodies like anti-TPO, which stands for thyroid peroxidase antibodies. This is not considered to be a screening test and is not indicated in people who have a normal TSH in general. However, if people have subclinical hypothyroidism where their TSH is a little elevated and their free T4 is normal, in people who have an enlarged thyroid gland, in people who have a personal history of autoimmune disease or a strong family history of autoimmune thyroid disease or other types of autoimmune disease, if they're pregnant or they're going through fertility planning or if they develop hyperthyroidism after they deliver, it all makes sense to check these antibodies. But in general, they're not recommended as a screening test. Knowing that one in four women will develop hypothyroidism and eighty percent of all autoimmune disease happens in women, I tend to check it more frequently than not, but the guidelines say that it's not necessarily indicated. So you really want to tailor it to your specific situation, and this is where that discussion with your doctor becomes really important. Now let's talk about myth number four, which is that subclinical hypothyroidism always needs treatment, meaning when your TSH is elevated but your T4 and T3 are normal, that you should be started on thyroid medication. This is hard because the reference ranges are all over the place. Like, if you look at LabCorp or Quest or your local hospital lab, they'll all be slightly different. So what is truly the range in which we would consider treating? TSH that is above the upper limit of the reference range of the lab with a normal free T4 is technically means that you have enough circulating thyroid hormone to keep your tissues working properly and you can see this in up to 10% of the adult population. Thyroid disease is more common in female patients than in male patients. Age also matters. TSH will naturally rise as we get older. So sometimes when we have patients who are 70 or older and their TSH is kind of in that borderline range, we may not need to treat them because they may feel fine, and in putting them on thyroid medication, we can actually make them a little hyperthyroid, which has implications for their heart and their bones. So you have to be really careful about that. Now, if they have positive antibodies and they're having symptoms of hypothyroidism, it may be a reasonable consideration. But again, this is a nuanced conversation with your doctor to make sure that you're getting the right advice. There was a recent study from the UK that looked at about 22,000 patients and found that the cardiovascular benefit from levothyroxine was actually limited to people whose TSH level was over age-specific ranges. Now, these age-specific reference ranges are not used frequently, nor are they published by the labs frequently, but the study was interesting because it basically told us that a single fixed cutoff for all people is not the right answer. These things are going to vary a bit with age, so a higher TSH might be better for somebody over the age of seventy compared to somebody who is in their twenties. So again, a very nuanced discussion is needed with your doctor. So let's talk a little bit about the evidence in older adults. So in patients who are sixty-five and older, there's actually not any existing evidence that levothyroxine is beneficial for subclinical hypothyroidism. So there was a trust trial that was done in twenty seventeen and published in the New England Journal of Medicine that looked at seven hundred thirty-seven adults sixty-five plus on levothyroxine versus placebo, and they actually found no difference in hypothyroid symptoms, meaning like fatigue, quality of life, their cognition, their blood pressure, their weight, or their vascular markers one year out for being on that therapy. And a second analysis that looked at this also found that the people who had the most symptoms also did not feel any benefit. So they really did try and narrow in on who was feeling symptoms concerning for hypothyroidism the most, and treating them when they had subclinical hypothyroidism didn't actually produce any benefit to their symptoms. And then there was another combined analysis of adults eighty and older from two separate trials that basically found the same thing. Treatment with levothyroxine, can increase the risk of heart arrhythmias like atrial fibrillation, can increase the risk of osteoporosis, and can increase mortality. But It's the over-treatment that actually does those things. So if you are treating somebody who doesn't need it, the odds that you put them into hyperthyroidism and put them at the risk of all of these other things is going to be there. So what we call iatrogenic thyrotoxicosis, which means becoming hyperthyroid from taking too much levothyroxine or another thyroid hormone formulation, and making that person's TSH become too low, so under point four, that will increase the risk of atrial fibrillation and osteoporosis and fracture risk. And this has been well established in the data, and it's common. It's noted that fifteen to thirty-eight percent of people on levothyroxine have a TSH that's below range, meaning they're over-treated. And a recent Journal of the American Medical Association study found that sixty-four percent of older adults who are now on low-dose levothyroxine, meaning less than fifty micrograms a day, could probably successfully stop their medication entirely and not have to go back on it, which means that they were probably treated unnecessarily in the first place. So let's circle back to levothyroxine that has been appropriately dosed. And I can't tell you the number of people who come into my office and they're like, "Oh, I just read on the insert for my levothyroxine that it causes osteoporosis, and I have osteoporosis." And we look back, and their thyroid levels have been normal the whole time. That levothyroxine has not caused their osteoporosis. It's truly only if you over-treat somebody and you make them hyperthyroid. And this has been shown in a meta-analysis of five observational studies and two randomized control trials that showed that if you have a normal TSH, and you're on thyroid hormone, your all-cause mortality or cardiovascular mortality was actually appropriate or lower because you weren't being overdosed. So the risk isn't with the medication, it's all with the dose and whether the medication was indicated to begin with. For the general population, we say that treatment is appropriate when the TSH is consistently greater than ten, and that's endorsed by the American Thyroid Association, the European Thyroid Association, and other societies. Younger symptomatic patients with other risk factors will benefit from treatment. And then in pregnancy or preconception, we want to make sure that the TSH level is below 2.5 prior to conceiving a pregnancy and even throughout the pregnancy to make sure enough thyroid hormone is going from mom to the baby. Because for the first 20 to 24 weeks in utero, the baby doesn't have a formed or functional thyroid gland, so it's dependent on mom And another claim that I hear made over and over again is that thyroid medication is important for reducing your cardiovascular disease risk. I think that that benefit A lot of the data around this statement is observational, and a lot of the benefit is actually in younger patients versus older patients. So we need to be really careful about who we're treating when and how and with what dose. So again, this is not about whether thyroid medication is safe. It is safe when it's dosed appropriately and to the right patients. So this isn't about whether thyroid medication is safe. It's about, number one, did you need it in the first place? And number two, did you get the right dose? So those are I want to switch gears a little bit now and talk about the menopause thyroid connection that no one explains. So this is kind of where my two specialties collide, the endocrinology and the women's health, and I think we do a really crappy job of explaining it to people. Perimenopause and menopause change how we interpret thyroid tests and how we manage thyroid medications. I always tell my patients that thyroid symptoms and menopause symptoms are kinda like a Venn diagram where the circles are almost entirely overlapping, and what gets left out is really the vaginal symptoms and the pelvic floor symptoms that we see with menopause that you don't necessarily see with thyroid conditions. Most of the symptoms can actually occur in either condition, so hot flashes, palpitations, sweating, mood changes, weight fluctuations, sleep disturbances. These are core menopause symptoms, and they're core thyroid symptoms, so that overlap is really not subtle at all. And even in women whose thyroid function is completely normal, the severity of the menopause symptoms can correlate with the thyroid hormone levels It's kind of like the two systems are talking to each other, and because of this overlap, several professional societies recommend a lower threshold for checking TSH in perimenopausal women. That's why I test the way that I do. You don't need a higher threshold, you need a lower threshold because there are so many things that are going on and changing all at once. And so menopausal symptoms should prompt testing, but not make you think that, "Oh, I don't need to test this person for thyroid disease." Because the TSH starts rising as we get older, your TSH reference range is probably not going to be the same as when you were 28 when you're in your 40s and 50s, because that's really when that upper limit starts rising, and that's earlier than when it happens to men. For men, that doesn't really start to happen until they hit 60 plus. There have been, several studies looking at this. There was a large 2025 Annals of Internal Medicine analysis of NHANES data that found that applying age, sex, and race-specific TSH reference ranges actually reclassified almost 50%, so 48 and a half percent of people who were previously diagnosed with subclinical hypothyroidism as totally normal, especially in women and older adults. A 2026 population study in Hong Kong found that same pattern, that age and sex-specific ranges cut the proportion of people who were classified with thyroid dysfunction from 30.8% down to 18.6%. So the point is that we're over-diagnosing thyroid conditions when people don't actually have them. And that overall, a TSH of five to six in a 55-year-old post-menopausal woman might be normal for her and not subclinical hypothyroidism that requires treatment. I have several patients in my practice who feel terrible when we lower their TSH below five, and I have let them be at higher TSH levels if we're keeping their free T4 normal and their symptoms are under control and they're not having any weird metabolic things like high cholesterol or other changes like weight gain that are happening to them Now interestingly, thyroid disease does increase as we age, so it's important to know that even with those higher cutoffs, more people will develop thyroid dysfunction as they age There's a Korean study of over fifty-three thousand women that showed both overt, meaning clear diagnosis of hypothyroidism, and subclinical hypothyroidism were more common in late perimenopause and postmenopause, even when we adjusted for age. And in women over sixty, subclinical hypothyroidism was present in up to about twenty percent of the population. And there are other studies that show that that number can be as high as twenty-three or twenty-four percent. And here's the part that almost no one tells patients. Estrogen therapy is going to change your thyroid numbers a little bit. I will always reassess thyroid levels after I start somebody on hormone therapy if they're already on levothyroxine. Oral estrogen increases a protein called thyroxine-binding globulin, and this is the protein that thyroid hormone binds to, which can raise your total T4, and it can increase your levothyroxine requirement because what's floating around in your blood gets bound up by this protein and your free T4 levels can drop, and you can feel more hypothyroid. So in a trial that looked at this, it was estimated that about three out of ten hypothyroid women, so about thirty percent, on oral estradiol needed a dose increase. Now interestingly, the transdermal estradiol, the patch, because it's not going through the liver, has a minimal effect on the thyroxine-binding globulin, and we may not have to adjust the dose as much. Additionally, if thyroid function is normal, oral estrogen will cause a temporary rise in TSH because that binding protein increases, but then it levels out because your thyroid gland compensates. And that happens in about eighteen percent of women. But if you're hypothyroid and you can't compensate, and your free T4 falls, that's when we're going to adjust your medication. So the bottom line is, if you're starting menopause hormone therapy, and you're hypothyroid, we're going to need to repeat your thyroid function test six to eight weeks after starting oral estrogen and adjust your levothyroxine dose. And if that is something that's happening, you can talk to your doctor about whether transdermal might make more sense for you. I personally will check with transdermal estradiol starts as well sometimes if people are starting to develop worsening symptoms And one more thing I want to call out is that avoiding overtreatment really matters. We don't want to overtreat with levothyroxine because as estrogen levels fall, that has an effect on your cardiovascular disease risk as well as your risk of developing osteoporosis. And if we're overtreating women and giving them thyroid hormone when they don't necessarily need it, we're also enhancing those risks. So you have to talk to your doctor. You have to make sure that they're aware of your history, of your family history, of what your symptoms are so that you can make the best decision based on your lab tests. Because each age range deserves some nuance. So if you're perimenopausal and your symptoms overlap with thyroid symptoms, that's a reason to test. It's not a reason to assume it's just menopause. And if you start estrogen while you're on thyroid medication, that's a reason to retest your thyroid levels, not just a reason to guess, like, you know, what's going to happen to those levels. So if you're symptomatic and you're told that your thyroid is fine because you had some screening lab tests, here's what to ask. And notice that nothing on the list that I say is going to be to demand a full panel. So the first question I want you to ask your doctor is, "Does my clinical picture fit one, one of the specific scenarios where testing beyond TSH actually adds information?" So, "Do you think I have a pituitary disorder? Were there any recent medication changes that could affect my thyroid levels? Could I be pregnant?" That's more common in midlife than you would think. Or, "Was I really sick when I had those levels drawn?" Next question would be, "If my TSH is normal, what else could explain these symptoms? Has anyone evaluated me for perimenopause? Has my estradiol been checked?" Has anyone evaluated me for perimenopause? The other thing you can ask, is my TSH being interpreted against an age and sex appropriate reference range or is it just a standard lab cutoff? The next question is, could my insulin resistance be contributing? What about my iron levels? What if my TSH is mildly elevated? Is there any evidence for me to be on treatment at my age? And then if I'm starting estrogen and I'm on levothyroxine, when should we recheck my TSH and should I be on transdermal instead of oral? And if you're already on levothyroxine and still don't feel well, that's also a real clinical conversation that's worth having, and I can do a whole separate episode on that about the different thyroid hormone formulations that are out there and what combinations you can try, but we'll get to that another day. The next episode in this thyroid series is going to look at all of the different myths that we hear online and in the wellness space, and I'm excited to break that down for you all. So make sure you tune in to talk about the diet and treatment myths, cruciferous vegetables, soy, gluten, desiccated thyroid, iodine supplements and more. That's it for today, but the conversation doesn't have to stop here. Come find me on Instagram or TikTok at drpatilsisodia. And if something from today's episode resonated, I'd genuinely love to hear about it. Leave a review, which makes the podcast searchable, share the episode, or just send me a message. The more women who have access to this information, the better. I'll see you next week on the next episode