In practice, you have almost certainly seen it for yourself: the thyroid is not just a TSH reading.
Fatigue, weight gain, feeling the cold, digestive trouble, low mood… All possible signs, yet rarely specific. And above all: rarely isolated.
Thyroid function is a complex puzzle, shaped by the microbiota, the liver, the adrenals, micronutrient deficiencies and endocrine disruptors…
That is exactly the focus of this webinar led by Florence Pinheiro Ortolan: understanding the functional causes of a sluggish thyroid, long before overt hypothyroidism, and building care that is global, causal and personalised.
This guide sets out its key lessons, to help you investigate, spot the right signs, identify the right levers, and understand how micronutrition and the thyroid fit together in clinical practice1.
1. Telling overt hypothyroidism apart from functional slowing
As you know, a TSH “within range” does not mean the thyroid is working properly.
As Florence Pinheiro Ortolan reminds us, it is essential to distinguish overt hypothyroidism (with a medical diagnosis) from functional slowing, which does not meet pathological criteria but already impairs overall function.
Overt hypothyroidism: TSH > 5.5 or even > 10, a suggestive work-up, and allopathic treatment often started.
Subclinical hypothyroidism: TSH between 2.5 and 5.5, with marked clinical signs but no diagnosis made.
Functional slowing: TSH > 1.5 plus signs present. No disease identified, but suboptimal thyroid function.
In this last case no label is applied, yet the patient often shows characteristic signs: persistent fatigue, feeling the cold, weight gain, sluggish transit, hair loss, unstable mood…
These are often multi-symptom patients, adrift from one consultation to the next, for whom functional thyroid support can change everything. The picture is not always clear, but repeated signs should raise a flag.
In functional health, a TSH > 2 can already be a warning signal, especially when several symptoms are present.
The aim is therefore not to make a diagnosis, but to identify functional slowing so the underlying terrain can be supported early.
2. Choosing the right assessments to document the terrain
When “standard” blood work shows nothing, the practitioner’s role is to look more closely at what may be holding thyroid function back.
Florence Pinheiro Ortolan sets out two useful types of assessment: those you can prescribe, and those the patient can order directly, with support.
Here are the markers she recommends targeting, case by case:
What to measureWhyTerrain-specific pointsTSH, free T3, free T4Assess overall thyroid functionTSH > 2 + low T3 → slowed conversionReverse T3Explore the impact of chronic stressCommon with fatigue + adrenal overloadUrinary iodine (spot or 24h)Screen for a deficiency or an excessAvailable as a direct-order test, to be interpreted with cautionZinc, selenium, iron, B12Essential cofactors for hormone conversion and activationMeasure zinc in whole blood, plus serology or ferritinVitamins A and DRegulation of hormone receptors, immune supportWatch for functional deficiencies even when the result looks “normal”HomocysteineIndirect marker of B9/B12 deficitsUseful with cognitive or cardiovascular signsLiver function (GGT, transaminases)Explore hepatic detoxification capacityRelevant with a congested liver or associated digestive trouble
These assessments are not for routine use; choose them according to the symptoms, the patient’s history and their eating habits.
3. Supporting thyroid function through micronutrition
Once the brakes have been identified, the aim is to supply the right nutrients at the right moment, according to the patient’s terrain.
Florence Pinheiro Ortolan advises acting with precision and judgement, taking account of deficiencies, the clinical profile and the overall level of fatigue. She reminds us that some profiles call for closer vigilance:
Vegetarians and vegans, often deficient in B12, iron, zinc and iodine
Pregnant women, whose iodine and selenium needs increase
Patients with chronic fatigue or post-burnout, in whom adrenal support is the priority
In these cases supplementation can be valuable, provided it is well matched and well tolerated.
Here are the actives most often used in thyroid micronutrition, case by case:
ActiveMain roleCautionsZincT4 → T3 conversion2Measure in whole blood before supplementingSeleniumEnzyme cofactor, antioxidantWatch for overdosing over the long termIronOxygen transport, thyroid receptorsFerritin testing is essentialVitamin B12Hormone synthesis, energy metabolismFrequently low in vegetarians and vegansVitamin AActivation of thyroid receptorsCan be low even when the work-up is within rangeIodine (seaweed)Thyroid hormone synthesisTo be avoided without an identified deficiencyAshwagandha, rhodiolaCortisol regulation, adrenal supportSuited to chronic fatigue or high stressCombined formulationsOverall support for the thyroid terrainCheck the balance of doses and the tolerability
These supplements can meaningfully support thyroid function, provided they sit within a global, well-reasoned approach.
4. Working the terrain in depth for lasting results
Supporting the thyroid goes beyond correcting deficiencies: it is often the patient’s whole ecosystem that needs rebalancing3. Florence is emphatic: when the thyroid is sluggish, digestive disorders are almost always present.
SIBO, candidiasis or hypochlorhydria can slow nutrient absorption, create low-grade inflammation and block hormone conversion.
Liver support is equally central: if the detoxification pathway is slowed, T4 is not converted properly into T3 and circulating hormones work less well. Without deep work on the gut, the liver and the adrenals, the thyroid does not restart.
Finally, lifestyle plays an often neglected role: chronic stress, prolonged calorie restriction, disturbed sleep… All these factors help to put the thyroid on pause.
What about a “normal” TSH, nodules or Levothyrox?
Even on treatment or with a normal TSH, clinical signs can persist. Florence urges you not to stop at the number: if the patient is exhausted, constipated and always cold, the terrain deserves support.
Working on hormone conversion, stress management and key nutrient status remains useful, including alongside replacement therapy.
Micronutrition and the thyroid: what to remember
A sluggish thyroid, a TSH “within range”, an exhausted terrain…
The link between micronutrition and the thyroid opens up concrete clinical possibilities, provided you explore every dimension: assessments, underlying causes, at-risk profiles and well-matched supplements.
By building these markers into your practice, you will spot the patients concerned more readily, and act early, with rigour and precision.
Would you like to know more about the micronutritional management of thyroid disorders? Do get in touch!
