Hormone Health Hub: Expert Insights on Testing, Balance & Better Living — thyroid hormone conversion

Normal thyroid blood tests don’t always explain why patients still suffer from fatigue, cold intolerance, brain fog and weight gain. In this in-depth clinical article, ZRT Laboratory explains the critical role of selenium in thyroid hormone synthesis and T4-to-T3 conversion, how heavy metals like mercury and arsenic sequester selenium and inactivate protective antioxidant enzymes, and why this can trigger Hashimoto’s thyroiditis — even when TSH, T4 and T3 appear normal.

Iodine deficiency is more common than many realise. This guide walks through how to assess iodine status using dietary recall, symptom profiling, and a three-part laboratory panel — including thyroid function, thyroglobulin, and urinary iodine and bromine testing.

The thyroid gland is under constant threat from modern life — oestrogen dominance, chronic stress, iodine and selenium deficiency, heavy metal toxicity and xenoestrogen exposure all suppress its function. This article outlines 7 key action steps you can take to protect your thyroid, from hormone rebalancing and stress reduction to targeted nutritional support and testing.