When Exhaustion Becomes Something More
I was so tired. I needed a new word for tired. I felt exhausted and incapacitated, utterly drained and hollowed out. It was like my brain and body were fading. And yet, these words are still not descriptive enough to relate how I felt. Getting out of bed felt gruelling, punishing. I was 24 at the time, in my 4th year of my PhD programme at Purdue University. I was newly engaged and so in love with my soon-to-be husband. Really good things were happening in my life. And I could barely function.
On the weekends, I slept until noon, got out of bed to have a bite of breakfast, and would go back to bed until 4 in the afternoon. I could only stay up with my fiancé for a little while in the early evenings, just to go back to bed around 8. This went on for months. At some point, he even asked me if I enjoyed my weekends and I distinctly remember saying “well of course, that’s when I get to sleep in.” During those days, he liked to tease me, saying I was the human equivalent of a sloth. I did not find that amusing.
Not That Many Symptoms — Or So I Thought
I refused to believe that there was anything actually wrong with me — after all, I was young and supposed to be healthy. I attributed my fatigue to the high demands of graduate school, rather than to something internal. My blood tests for all the typical CBC parameters were normal-ish, with the exception of mildly reduced iron stores. I did not have all the typical symptoms of thyroid dysfunction — I had always felt cold for as long as I could remember, my hair was always pretty thin and my skin on the dry side. I did not gain weight. In fact, my “bad” lipid parameters were all on the low end. Also, I did not feel that depressed. In fact, I did not feel much of anything, except debilitating fatigue.
Eventually, I did go to the doctor once more — to say that I thought I was fine — but my fiancé wanted to spend more time with me, so he insisted that I try to figure out why I was sleeping so much.
Diagnosis: Hypothyroidism
After a few additional tests, I learned that my Thyroid Stimulating Hormone (TSH) level was hovering in the mid-thirties. And so, I received my diagnosis of insufficient thyroid function — hypothyroidism. And what a difference a little bit of levothyroxine (synthetic thyroid hormone replacement) made! I felt like a new person.
No Known Cause
Who knows why I developed hypothyroidism. In most cases, the medical community agrees that causes of hypothyroidism are idiopathic — meaning without a known cause. In retrospect, thyroid disease is not uncommon for someone who grew up 200-some miles away from Chernobyl, or for a young woman taking birth control pills. I cannot change my past. But what I can focus on now is taking levothyroxine in the morning on an empty stomach and monitoring thyroid function regularly.
If you recognise these symptoms — persistent fatigue, feeling cold, thinning hair, dry skin, or low mood — our Essential Complete Thyroid Testing Profile (Blood Spot) measures TSH, Free T4, Free T3 and TPO antibodies from a simple finger-prick at home.
Understanding Your Thyroid Lab Results
Why TSH Alone May Not Be Enough
Although I felt much better shortly after initiating thyroid replacement, it took me years to feel like I had regained that vigour and zest for life. At the time of my diagnosis, the accepted reference range for normal serum TSH went up to 10 mIU/L. For me personally, being closer to 10 meant that I would get out of bed in the morning without difficulty, but I also fatigued easily — mentally and physically — not completely wiped out, but sufficiently lethargic. It took time for my medication dosage, TSH levels and symptoms to achieve their optimal balance.
In the third National Health and Nutrition Examination Survey (NHANES III), of 17,353 people evaluated, 80.8% had a serum TSH below 2.5 mIU/L with a mean serum TSH of 1.50 mIU/L. For women trying to conceive or already pregnant, the American Thyroid Association recommends TSH intervals of 0.2–2.5 mIU/L. When I got pregnant, my levothyroxine dosage was doubled right away and my TSH levels were monitored regularly.
The Full Thyroid Picture: T3, T4 and TPO Antibodies
In many cases, measuring TSH alone to diagnose hypothyroidism is not enough. Free T4 and Free T3 measurements, when low alongside a normal TSH, may still suggest hypothyroidism. Elevated thyroid peroxidase (TPO) antibodies typically indicate autoimmune thyroiditis (Hashimoto’s disease) — a condition in which the body produces antibodies that attack the thyroid gland. Lastly, thyroglobulin can show up in the bloodstream at elevated levels when iodine status is very low.
Even with normal levels of thyroid hormone, there are instances in which thyroid hormone activity can be affected at the molecular level by things like stress hormones or heavy metals. If you are on thyroid medication and still not feeling well, it is worth checking whether elevated cortisol or adrenal dysfunction is interfering with thyroid conversion. Our Adrenal Stress Profile (Saliva) measures cortisol at four time points across the day alongside DHEA-S — a practical companion test for anyone managing thyroid dysfunction.
Conclusions
If you suffer from the common symptoms of hypothyroidism — fatigue, cold intolerance, hair thinning, dry skin, low mood or brain fog — check your thyroid levels and talk to your doctor about thyroid hormone therapy. For a comprehensive starting point that covers thyroid alongside key metabolic hormones, our Weight Management Profile combines TSH, Free T3, Free T4 and sex hormones in a single at-home kit — ideal for women who suspect both thyroid and hormonal imbalances may be at play.
A simple finger-stick blood spot collection, dried on a filter card and sent directly to the laboratory, is all it takes to get a clear picture of your thyroid health from home.
Originally by Dr. Kate Placzek, ZRT Laboratory. Reproduced with permission. Last reviewed: May 2026.