Midlife Thyroid Health and the Hormone Connection You Can’t Ignore
- D.D. Forrest
- May 15
- 9 min read
Updated: May 21
Welcome to midlife, where our hormones start to decline just as life gets the most demanding. Kids. Careers. Aging parents. No one warned us it would feel quite like this. While there seems to be a ton of info circulating online about HRT, I feel like there's a huge missing piece of the conversation: our thyroid! Maybe you've jumped on the hormone replacement bandwagon, maybe not; perhaps you've been trying the new weight-loss drugs that seem to be working wonders for, well, most people, maybe not. But if you find that you're getting lackluster results, it might be because you (or rather your doctor) forgot to address thyroid health.
✅ Feeling unmotivated and don't know where your giddy up went?
✅ Has your metabolism suddenly left the building?
✅ Do the little things stress you out just as much as the life-altering issues in your life?
✅ And why, in the name of all things holy, does your hair keep falling out?
Thyroid hormones are the unsung heroes of energy, mood, metabolism, resilience, and hormone balance, among other key functions. And yet, a void remains in attention to thyroid health within our current medical model.
Jump to:
Your Thyroid Controls More Than You Think
If you’re new to thyroid health or need a refresher, here’s the quick version: your thyroid is a small gland with an outsized impact. It controls how fast or slow your body runs, regulating metabolism, energy production, mood, heart rate, digestion, and even your menstrual cycle. And when it’s not working properly, everything feels off.
The problem? Most conventional doctors only run one test, the TSH (thyroid-stimulating hormone), which doesn’t provide the full picture. You could have sluggish thyroid function or poor hormone conversion and still fall into the “normal” range. This is why I always recommend a comprehensive thyroid panel, which includes free T3, free T4, reverse T3, and both TPO and thyroglobulin antibodies. It’s also why many women are told their thyroid is “fine” when they know something is wrong.
In a previous blog, I broke down exactly what these tests mean, how to interpret them, and what patterns I consistently observe in midlife women. If you want to go deeper into that side of things, you can check it out here. But for now, let’s talk about why your thyroid might be struggling even more during midlife, and why your sex hormones and stress levels are in on it, too.
The Midlife Link: When Thyroid + Sex Hormones Collide
(Men, This Applies to You Too)
Most women in midlife notice that they start having what are erroneously referred to as "estrogen dominance" symptoms. They start feeling irritable, losing sleep, getting hot flashes, feeling brain fog, etc. This is mostly due to a precipitous decline in progesterone. Progesterone balances out our estrogen, and when it's too low to keep its side of the seesaw down, estrogen dominates. You can learn more about this perimenopausal imbalance in this post.
What does this have to do with your thyroid? Well, a lot. Estrogen boosts TBG, which binds thyroid hormone. That means less is available in its active form, so even if your labs look "normal," your cells might not be getting what they need. Progesterone, on the other hand, has the opposite effect, increasing the free levels of thyroid hormones and decreasing the binding of thyroid hormones to TBG. On the other hand, without sufficient thyroid hormones circulating, the ovaries can't produce enough progesterone. It's a very intricate circular dance.
And for you gentlemen, don't think you get off easy here. As testosterone levels start to decline in midlife, this will impact your thyroid function. With normal T level, you'd have plenty of sex-hormone-binding globulin (SHBG) to shuttle that testosterone to your cells. However, as your T levels start to decline, there is less SHBG, which not only means that less testosterone reaches its intended destination, but also results in more "free T" circulating. This unbound testosterone can then be aromatized, or converted, into estrogen, often in excess. And what did we learn about too much estrogen? It lowers your availability of free T3. That's why, whether you're male or female, we need to look at how shifting sex hormones affect the thyroid, and vice versa.
And Then There's Stress...
Stress hormones and thyroid hormones also work together to help you navigate all life throws your way. Through various feedback loops and brain signaling, the adrenal glands, which produce primarily cortisol and DHEA, work in conjunction with the thyroid gland to ensure that your metabolism, stress response, and energy levels are optimized. But if stress is chronic, the signalling gets dampened, and low thyroid function can ensue.
This is further complicated when, in midlife, our production of estrogen, progesterone, and testosterone from our ovaries and uterus declines. The adrenals attempt to compensate by increasing the production of these reproductive hormones, in addition to cortisol and DHEA. Needless to say, that's a lot of work for those little glands. The circular cross-signaling we discussed, which keeps the brain and hormone-producing glands working in synergy, starts to become clogged. The hypothalamus may stop sending signals to the pituitary gland to convey to the adrenals and thyroid to produce sufficient hormones. The pituitary might not be able to convey those signals, or the signals may just not be received. Regardless of how, increasing and chronic stress coupled with decreasing or erratic reproductive hormones is a perfect storm for thyroid dysfunction.
My Personal Story: Fertility, Birth Control, and Thyroid Clarity
One thing I haven’t yet mentioned is that thyroid disease has a strong genetic component. I only recently learned that my grandfather had hypothyroidism and was on thyroid medication, and my mother has been under-treated for decades. For years, she struggled with brain fog, low energy, hair loss, and dry skin, but her doctors brushed it off and focused on antidepressants instead. In her case, those medications were necessary, but it still frustrates me that no one was monitoring her thyroid beyond TSH. It was a missed opportunity to support her more holistically, and it’s something I now see all the time with clients. That family history is what led me to dig deeper when I began dealing with my own symptoms: low energy, low mood, dry skin, and eventually, infertility. I knew there had to be more to the story.
I was fortunate to find a doctor who, while Stanford-trained and practicing mainstream medicine, took a very functional and integrative approach to his practice. He said to me, "While your thyroid may seem fine by most labs, it might not be fine for YOU." What a concept!! You mean, we shouldn't all shoot for the same lab results? So, he started me on a low-dose thyroid supplement while I worked on cleaning up my diet, getting more protein, and cutting back on chronic cardio. Lo and behold, I was pregnant within a year. Not to say that the thyroid was the only issue, but lower thyroid function was contributing to my lower progesterone, which, it turns out, you need a ton of to have a baby. Also, my go-go lifestyle, coupled with a low-calorie diet for too long, likely contributed to thyroid dysfunction. It's all connected!
Fast forward 15 years (yikes), and I'm still on the same brand of thyroid replacement. BUT- my dose has changed at least 10 times since then. Life stress, gut health, energy needs, and hormone shifts, all of which fluctuate, necessitate adjustments to thyroid dosing. For this reason, I ensure to run a complete thyroid panel at least twice a year. Now that I'm on HRT (estrogen, progesterone, and testosterone), every time I make a tweak to those doses, I have to check thyroid function too. Now you know why. If you are currently on thyroid support, please have your labs checked every six months or so, and work with your prescriber to optimize your dosing and its effects.
What I See in My Clients—Overlooked, Misdiagnosed, Missed
The dismissiveness that my mother dealt with still seems to run rampant among both endocrinologists and internists. I need to tread lightly here, as I am not a licensed prescriber, nor can I diagnose disease. However, I cannot tell you how many times I have helped clients uncover thyroid issues over the years. And I'm not talking low-level "subclinical" hypothyroidism. I'm talking nodules that were visible and still dismissed. Women who were so fatigued that they wanted to quit their jobs. I'm talking about clients put on antidepressants, insulin, and statins, but were walking around with dysfunctional thyroid glands. Why?
After reading up on it, I realized that this is how doctors are still trained, and it doesn't seem to be changing anytime soon. If a patient needing thyroid replacement can even get a prescription, it's usually for a T4-only medication (levothyroxine). Which, for many people lacking a healthy gut and liver, can not be converted to T3, so they don't get any relief. I won't get too in the weeds here, but if you want to learn more, I highly recommend the books Reversing Hashimoto's by Anshul Gupta, MD, and Rethinking Hypothyroidism by Antonio Bianco, MD.
What I can do for these clients is help them support their thyroid health by taking a big picture view of why it's not optimal to begin with. We focus on consuming a sufficient amount of protein, carbohydrates, and fiber. We work on stress management, regular exercise (not too much), and getting quality sleep. We work to keep inflammation tamped down and maintain their natural detoxification pathways. There's a lot we can do to support thyroid health without even getting a prescription. However, I also help them advocate for themselves by getting a comprehensive thyroid panel done, requesting an ultrasound to measure and monitor thyroid nodules if necessary, and having an informed conversation with their doctor once they receive the lab results.
The Lab Work You Need (and May Need to Ask For)
By now, I'm sure you're thinking, "I need to get this checked out." You're right. If you are diligent about getting your annual physical, your doctor will likely include a TSH (thyroid-stimulating hormone) test. However, all this tells us is how loud the signal is from your pituitary gland to your thyroid gland. If you already have plenty of thyroid being produced, it's low; if too little is being made, it becomes louder/higher. It does not tell us if your thyroid gland is responding to the signal being given, how well you're converting T4 to T3, how much active thyroid hormone you have circulating, if your stress response is inactivating some of your thyroid hormone, or if you are having any autoimmunity reactivity to thyroid. That's a lot TSH doesn't tell you.
If you would like to take a deeper dive and assess the health of your thyroid, here is a comprehensive list of tests I would recommend. Just keep in mind that once you have those results, you'll need to work with a practitioner to understand what they mean and how you can optimize your thyroid health to feel your best. I have physicians whom I refer my clients to. Please note that the lab ranges I suggest as "optimal" below are based on my research and may not align with those of your doctor. As I mentioned earlier, you are unique, and what feels best for you may be very different from what feels best for your neighbor. For a more complete understanding of these markers, please refer to my previous blog post.
TSH–Thyroid Stimulating Hormone: 0.5-2.5 uIU/mL or less (lower = hyperthyroid; higher = hypothyroid)
FT4–Free (unbound) Thyroxine: 1.4-1.8 ng/dL
FT3–Free Triiodothyronine: 3.8-4.4 pg/mL
RT3–Reverse Triiodothyronine: ratio to FT3 <10
TPOAb–Antibodies to Thyroid Peroxidase: zero (elevations indicating Hashimoto's)
TgAb–Antibodies to Thyroglobulin: zero (elevations indicating thyroid autoimmunity)
If you suspect autoimmune hyperthyroidism (overactive), you may ask to test TSH receptor antibodies, thyroid-stimulating immunoglobulins (TSI), or thyroid-binding inhibitory immunoglobulins. As Graves' disease is relatively rare, I do not often ask clients to request these.
What to Do Next: You’re Not Alone + Support Options
Thank you for hanging in there with me on this one. If you or someone you care about is struggling with their thyroid or hormone health in general, you're not alone. This is a figure-outable situation. With objectivity, detective work, and support, you can find a clear path forward. I invite you to book a discovery call with me to explore how I can help guide you toward finding your unique path to feeling better than ever. I don't want to just restore your wellness to how you used to feel. I'm here to help you feel fabulous!
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We are a community of women going through this midlife shift together. We learn, listen, and lift each other. Each month, I address a topic related to midlife hormone health (such as thyroid) and give actionable guidance on how to start feeling better! I take questions, offer complimentary coaching through our online chat, and offer many resources (from workout templates to labs to consider to books to read). All the live sessions are recorded and available within our online community.
This is not your grandma's midlife; it's a VITAL SHIFT. Membership is now open, with no joining fee.
Yours in health,
D.D. Forrest
Disclaimer: The information in this blog is for educational and informational purposes only and is not intended as medical advice. While I strive to share evidence-based insights, this content should not replace professional medical guidance. Always consult with a qualified healthcare provider before making changes to your diet, exercise routine, or healthcare plan, especially when addressing hormone health and midlife transitions.
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