Hormone Health Hub: Expert Insights on Testing, Balance & Better Living — selenium testing

Urine, serum, plasma, whole blood, red blood cells, feces, hair, fingernails—the list of biological samples used for element testing is long. But choosing the right sample type is one of the most critical decisions in producing results that are clinically meaningful and scientifically valid.

Brazil nuts are widely used as a natural selenium supplement, but the selenium content in each nut varies enormously depending on soil conditions, region, and even individual trees. While selenium is essential for thyroid function, antioxidant defence, and overall health, both deficiency and excess carry serious risks. This article explains why Brazil nuts are so variable as a selenium source, what the safe daily intake looks like, and why testing your selenium levels is the most reliable way to know whether your intake is adequate, insufficient, or dangerously high.

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.

Learn why the biological sample used for element testing — urine, whole blood, serum, hair, or nails — can dramatically change how toxic and essential mineral results are interpreted. Discover how different sample types reveal recent intake, long-term exposure, body burden, deficiency, or chronic toxicity for elements like mercury, lead, cadmium, arsenic, selenium, zinc, copper, iodine, and magnesium, and why choosing the correct testing method is critical for clinically meaningful results.