Months after my second daughter was born, during one of the most stressful seasons of my life, I gained nearly fifteen pounds in a matter of weeks. My diet had not changed and I was still moving, but my clothes no longer fit, my hair was coming out in handfuls, and brain fog had settled over everything. Because of my training, I ran a full thyroid panel. My TSH had risen to 5.7 with low free T4 and low free T3. I had developed hypothyroidism. Once I treated it and addressed the stress and cortisol that likely triggered it, I lost about ten pounds within two weeks.
I was fortunate. I knew what to look for and moved quickly. Most women do not, and that is not their fault. It is a gap in how thyroid disease is identified and treated. I have sat across from so many women who were exhausted, gaining weight despite eating less, losing hair, and struggling to think clearly, who had been to their doctor and been told their labs were normal. Their TSH was in range. Their T4 was in range. Case closed. But no one had checked their free T3. That is often where the real story lives.
An honest symptom inventory
Read these slowly, not as a checklist but as an honest inventory. Persistent fatigue that sleep does not fix. A heaviness in the morning that makes getting out of bed feel like an uphill climb. Cold hands and feet when everyone around you is comfortable. Weight that will not move despite real effort. Dry skin, hair thinning, or loss of the outer third of your eyebrows. Chronic constipation. Brain fog where words feel just out of reach. Low mood or a flatness that is not quite depression. Low libido, and heavy or irregular cycles. If five or more resonate, your thyroid deserves a closer look. And if you have already been told everything is normal, keep reading, because normal and optimal are not the same thing.
TSH is the message, not the hormone
The thyroid is a small butterfly-shaped gland at the front of your neck, and despite its size it influences nearly every cell: metabolism, body temperature, heart rate, digestion, mood, cycles, fertility, and your sensitivity to other hormones. When it runs well you rarely notice it. When it does not, you feel it everywhere.
Here is the piece most testing misses. The pituitary releases TSH to tell the thyroid to make hormone, so TSH is the message, not the hormone itself. The thyroid then makes T4 and T3. T4 is produced in the greatest quantity, but it is largely inactive. It is a storage form that must be converted into T3, the active hormone that actually enters your cells and drives energy, metabolism, and clarity. And only the unbound, free portion is available to your tissues. So you can have adequate total T4 and a normal TSH while very little free T3 is reaching your cells.
The pattern that gets missed
Under ideal conditions T4 converts efficiently into T3, but conversion is sensitive to stress, inflammation, blood sugar instability, nutrient deficiencies, toxins, and certain medications. When those are present, T4 can be diverted into reverse T3, an inactive metabolite. Think of it as a key that fits the lock but will not turn it. The result is a woman whose T4 looks fine and whose TSH may be in range, but whose cells are not getting the signal. She has every symptom of low thyroid, her labs say normal, and she goes home without answers. Adequate T4 with low free T3 and elevated reverse T3 is one of the most commonly missed presentations in women's thyroid health, and it is almost invisible unless the right tests are ordered.
What a complete evaluation looks like
If you have ever been told your thyroid is fine based on a single TSH, you were not given the full picture. A complete evaluation should include free T4, free T3, reverse T3, and thyroid antibodies. Together they tell the whole story: the signal, the production, the conversion, and whether the immune system is involved. Antibodies matter because Hashimoto's, an autoimmune condition, is the most common cause of low thyroid, and it is rarely just a thyroid problem. It is an immune one, which is why gut health and, for some, a gluten-free trial can be part of the conversation.
Production and conversion also depend on nutrients, especially iodine to make the hormone and selenium, the key cofactor that converts T4 into active T3 and protects the gland from oxidative damage. Without enough selenium, conversion slows no matter how much T4 is being made.
If this sounds like you, you are not imagining it and you are not being dramatic. The difference between feeling well and feeling unwell often lives in the exact tests no one thought to order. You deserve the full picture.
This post is drawn from Chapter 10 of my book, Where Faith Meets Medicine, where I walk through the complete thyroid panel, optimal ranges, root causes, and treatment options.
