Why “normal” bloodwork doesn’t always mean a healthy thyroid, and what pyrrole disorder has to do with it | By Sue Kira, Naturopath & Clinical Nutritionist
You’ve had the bloods done. Your TSH sits neatly inside the reference range, and your GP tells you everything looks fine. And yet you’re flat by 2pm, your hair is thinning, the weight won’t budge no matter what you cut, and some days your mind feels like it’s moving through fog. On top of that there might be an undercurrent of anxiety, disrupted sleep, and a fatigue so heavy that some days all you want to do is sleep. If that sounds familiar, you are not imagining it. You are far from alone.
Hypothyroidism is the most common thyroid disorder in Australia, affecting around one in every thirty-three of us, and it disproportionately affects women.¹ Hashimoto’s disease, an autoimmune condition in which the immune system gradually attacks the thyroid, is the most common cause. Yet in over 33 years of clinical practice and more than 25,000 consultations, I’ve seen the same pattern again and again: a person is unwell, sometimes for years, while their thyroid results sit just inside “normal.”
More Than Metabolism: What Your Thyroid Really Controls
Before going any further, it helps to understand exactly what your thyroid does. This small, butterfly-shaped gland at the base of your neck governs your metabolism, the rate at which your body converts food into usable energy. Its influence runs through nearly every system in the body: it sets the pace at which your cells burn calories, helps determine how quickly or slowly your heart beats, plays a role in keeping you warm or cool, shapes how quickly food moves through your digestive system, supports healthy brain development, and even keeps blood calcium levels steady through a hormone it produces called calcitonin.² It also has a hand in how deeply you breathe, whether you gain or lose weight, your cholesterol levels, and the rhythm of a woman’s menstrual cycle.³ When one gland carries this much responsibility, it’s easy to see why an under- or overactive thyroid can ripple out into almost anything, from your energy and mood to your weight and heart rate.
what your thyroid really controls
The Heart Connection
One of the clearest examples of the thyroid’s reach is its effect on cholesterol and cardiovascular health. An underactive thyroid consistently drives cholesterol levels up, and treating hypothyroidism with thyroid hormone replacement has been shown to lower total cholesterol by around 58 mg/dL and LDL, the “bad” cholesterol, by around 41 mg/dL on average.⁴ I saw this connection play out vividly in one of my own clients: a middle-aged man who had a heart attack that left specialists baffled, since his heart and blood vessels showed no abnormalities at all. When he first raised the possibility of a thyroid problem (after speaking with me), his doctor told him his thyroid was fine, a conclusion reached by looking at him rather than testing him, since he didn’t fit the typical overweight, cold-sensitive picture of an underactive thyroid. By the time he came to see me, he was living with the fear of another heart attack and no real answers. Proper testing told a different story: a significantly underactive thyroid, elevated homocysteine (an independent cardiovascular risk marker), low B12, and an undiagnosed gluten intolerance. Addressing the gluten, correcting his nutrient deficiencies, and supporting his thyroid brought his levels back into a healthy range within months. Six years on, he remains symptom-free.⁵
The Ripple Effect
The thyroid’s reach doesn’t stop at the heart. In women, thyroid dysfunction is linked to irregular cycles, difficulty conceiving, and a higher rate of pregnancy complications and higher risk of miscarriage, while in men it can lower testosterone and affect semen quality. Mood and cognition are commonly affected too, with depression, anxiety, brain fog and memory trouble all well documented in both under- and overactive thyroid disease, alongside the dry skin, thinning hair, disrupted sleep, and aching muscles and joints many people already associate with thyroid problems.⁶ An overactive thyroid in particular accelerates bone turnover, raising the risk of osteoporosis over time.⁷ Very few of these show up in isolation. More often they arrive as a cluster, quietly building on one another until someone finally asks the right question.
When “Normal” Isn’t the Whole Story
A single TSH reading is a screening tool, not a full investigation. In my clinic, a proper thyroid work-up looks at TSH alongside Free T4, Free T3 and reverse T3, thyroid antibodies (TPO and thyroglobulin), iron studies and ferritin, vitamin B12, B6 and D, zinc, selenium and iodine, cortisol rhythm, heavy metals, and markers of gut health. Thyroid hormone doesn’t work in isolation. It depends on a whole supporting cast of nutrients and systems, and a shortage anywhere along that chain can produce thyroid-like symptoms even when the thyroid gland itself is only part of the story.
“When the thyroid isn’t functioning well, it is often a sign that something deeper is driving it.”
Sue Kira
My approach is built around a simple sequence: Test. Clear. Nourish. Thrive. Test properly, clear whatever is driving the dysfunction, whether that’s gut inflammation, an old viral trigger, heavy metals or chronic stress, then nourish the body’s ability to heal, so it can move back toward genuine vitality rather than just a “normal” number on a page.
The Piece Almost No One Checks: Pyrrole Disorder
One of the patterns I test for that rarely comes up in a standard work-up is pyrrole disorder, also known as pyroluria.⁸ It describes an excess of a by-product of haemoglobin production called HPL (hydroxyhemopyrroline-2-one), a substance linked to oxidative stress in the body. Nutrients like B6, zinc, magnesium and antioxidants like selenium are often used to help support a person with pyroluria, along with looking at the drivers. I want to be upfront that pyroluria sits outside conventional diagnostic frameworks, and the evidence base for it is still thin and contested.⁹ That said, it is a pattern I have tested for and worked with clinically for decades, and one that shows up again and again in clients who also carry a thyroid diagnosis.
The overlap makes physiological sense once you look at what even just zinc and B6 actually do. Zinc is a required cofactor for converting inactive T4 into the active thyroid hormone T3, and one clinical study found that T3 levels improved in zinc-deficient patients once zinc was restored.¹⁰ Vitamin B6 supports the pituitary’s production of thyrotropin-releasing hormone (TRH), the very signal that tells the body to make thyroid hormone in the first place. In animal research, B6 deficiency alone was enough to induce a hypothyroid state, and it reversed once B6 levels were corrected.¹¹ Add chronic stress into the mix, which depletes both zinc and B6,¹² while also interfering with the body’s conversion of T4 into active T3,¹³ and you have three overlapping mechanisms all pulling in the same direction. Please note that not all B6s are created equally, but that’s another article.
In practice, this means someone with anxiety, poor stress tolerance, disrupted dream recall, sensitivity to light or strong smells, and pale skin that doesn’t tan easily, alongside classic thyroid symptoms like fatigue, brain fog and low mood, may be dealing with both patterns at once, each one making the other harder to shift. It’s one of the reasons a person can do “everything right” for their thyroid and still not feel like themselves.
A Familiar Story
One client, Brock, described years of searching for an explanation for his mood swings and unpredictable behaviour before a pyrrole screen finally gave him an answer:
“For years I searched high and low for answers for my mood swings and somewhat erratic and unpredictable behaviour. Sue ran some tests. I have pyrrole disorder. Sue helps me manage it NATURALLY. My life is refreshed, I am so alive.”
Brock, True Vitality client
Another client, Fleur, put words to a frustration I hear constantly from people whose labs come back “fine”:
“When doctors say your levels are fine, you start to feel it must all be in your mind.”
Fleur, True Vitality client
What This Means for You
If you’ve had your thyroid checked and been told it’s “normal,” but you still don’t feel like yourself, it may be worth widening the lens rather than accepting the single number at face value. A fuller picture, one built from comprehensive thyroid markers, nutrient status, whatever else is needed to get to the root cause, and, where the symptom pattern fits, pyrrole screening, often reveals what a single TSH test simply isn’t designed to show. You deserve to feel well, not just to receive a result that sits inside a reference range.
If this article has struck a chord, I’d love to help you connect the dots. I see clients in person at my Maroochydore, Sunshine Coast clinic and by telehealth across Australia and worldwide. You can find out more, read case studies, or book a consultation at truevitality.com.au.
References
- Hormones Australia. Hypothyroidism. hormones-australia.org.au/endocrine-diseases/hypothyroidism/
- Cleveland Clinic. Thyroid: What It Is, Function & Problems. my.clevelandclinic.org/health/body/23188-thyroid
- What Does the Thyroid Do? webmd.com/a-to-z-guides/what-does-thyroid-do
- American Thyroid Association. Treating Hypothyroidism Decreases Cholesterol Levels. thyroid.org/patient-thyroid-information/ct-for-patients/april-2021/vol-14-issue-4-p-6-7/
- Kira S. Heart Attack and Thyroid Connection: Case Study. True Vitality. truevitality.com.au/heart-attack-thyroid-connection-case-study/
- Medical News Today. Hypothyroidism: Effects on the Body. medicalnewstoday.com/articles/effects-of-hypothyroidism
- Medical News Today. Hyperthyroidism and Osteoporosis: The Link, Risk Factors, and More. medicalnewstoday.com/articles/osteoporosis-hyperthyroidism
- Kira S. What is Pyrrole? True Vitality. truevitality.com.au/what-is-pyrrole-by-sue-kira/
- Diet vs Disease. Is Pyroluria Real? An Unbiased Look at the Facts. dietvsdisease.org/is-pyroluria-real/
- Nishiyama S, et al. Zinc supplementation alters thyroid hormone metabolism in disabled patients with zinc deficiency. Journal of the American College of Nutrition, 1994;13(1):62-67. pubmed.ncbi.nlm.nih.gov/8157857/
- Wentz I. Vitamin B6 and Hashimoto’s. thyroidpharmacist.com/articles/vitamin-b6-and-hashimotos/
- Metagenics UK. 5 Vital Nutrients Drained by Stress. metagenics.co.uk/news/5-vital-nutrients-drained-by-stress/
- Rupa Health. The Stress-Thyroid Link: Understanding the Role of Cortisol in Thyroid Function within Functional Medicine. rupahealth.com/post/the-stress-thyroid-link-understanding-the-role-of-cortisol-in-thyroid-function-within-functional-medicine
To make a booking to see Sue, click here.
To make an enquiry email, click here for the Contact Page
Want to read more thyroid related articles? Click here.
For thyroid health FAQs, click here.